I have a newly-built 383 tpi in a 91 formula. It ran fine for the first few days, then began smoking badly after it was warmed up. The smoke is white, but I don't know how to tell if it is running rich or if it is burning anti-freeze.

I am not getting any error codes, and everything else seems to be working normally. Power is good. It does SUDDENLY sputter and die sometimes, but starts back easily. Its like someone puts their hand over the air intake and chokes it out. Don't know if thats related or not.

Being convinced of a rich mixture, I have changed the oxygen sensor twice, the last time I used a heated one since I am running headers. But this did not work, and the engine continues to have the same problem.

I have also changed the following items: MAP sensor, both temp sensors, fuel injectors, distributor, plugs, plug wires, and even tried a milder cam (and I don't care if I ever swap another cam).

I'm NOT convinced that its the mixture causing the smoke. The smoke does have a strong smell, and I have to keep changing the oil due to (suspected) fuel contamination, or at least it smells like it.

The engine is running about 11:1 compression, and is brand new. I have probably put about 200 miles on it since I installed it.

Any advice would be greatly appreciated.

A compression check would tell you if you have a bad head gasket. Each cylinder should read right about the same pressure +/- a couple pounds. The white smoke usually means coolant getting into a cylinder, it usually makes the exhaust smell kind of "sweet". Definately do a compression check.

If you have two adjacent cylinders that are low, that is tip off that the gasket blew between the two cylinders.

If you have fuel in your oil, maybe the gasket blew between a cylinder and an oil return passage.

Thanks, I haven't tried that yet. Do you think that a blown head gasket could also cause the engine to sputter occasionally?

Absolutely. Car heats up, gasket starts to leak, looses compression or gets a little water in the cylinder and it will run like crap.

White smoke = Coolant
Blue smoke = Oil Burning
Black smoke = Rich Gas mixutre

[This message has been edited by Black 67 (edited 08-27-2001).]

I'm glad I found this forum. I have actually had a couple of mechanics look at the car and tell me everything from "its burning oil" to "your cam is too strong for the computer so the mixture is off".

I didn't know that I could tell what's burning by the color of the smoke. Now that you guys have told me, I agree with your diagnosis. The problem did disguise itself well as a mixture problem, at least to an amatuer like myself.

I was sure it was the mixture except for one thing; no computer codes. Thats why I wrote to you guys and I'm glad I did.

I'm going to try to pull the heads sometime this week. I'll let you know what I find.

Thanks a ton for all your help!

Swapped the head gaskets and am on my way back up with the engine. I did not find anything wrong with the gaskets, at least from a visual inspection.

Also, I noticed that my pistons and combustion chambers were "sooted up" pretty good, which points back to the mixture. My plugs were pretty black, also. But, I do know that the engine ran rich before I changed to a heated o2 sensor, so its probably from that.

I did, however, find a couple of head bolts that were "soft". I may have missed torqueing one and that could have caused the gasket to leak.

I was wondering if the gasket could be leaky and still look ok to the naked eye?

Usually you can see a leaky head gasket. But it's not always obvious. Look for a carbon track (thin black line) between two cylinders at the narrowest point in the gasket. Also look for any type of damage between a cylinder and a water passage.

Did you do a compression check before you pulled your motor apart? That would tell a lot about your head gaskets and the general condition of your engine. It would confirm a bad head gasket if it failed.

Did any single cylinder look different than the others? If they all looked equally sooty than a head gasket or cracked block is less likely.

Definately sounds rich based on what you said about the cylinders and plugs. But the exhaust smoke would be black not white.

Are you running a lower temperature thermostat by chance? If you put a 160 thermostat in a TPI car without a chip, then the computer will never go into closed loop mode and will run rich. Basically, the computer thinks that the engine is still cold and keeps the mixture rich - kind of like keeping the choke on.

Also - before you put the heads back on look at them very closely for cracks between the valves or damage of any type. I think it's pretty uncommon for a Chevy small bock head to crack but that could cause the white smoke too.

[This message has been edited by Eric68 (edited 09-05-2001).]

Thanks for the reply. All of the pistons and combustion chambers were equally sooted. I did not find any "trails" from the passages either on the engine or on the heads.

I did check the heads for cracks, but did not find any, nor any evidence of one. As for the likelihood of a cracked head on a gm, I forgot to mention that I am using trick flow aluminum heads.

I did not do a compression check, as I did not have the proper tools. I wanted to take the heads off to check everything anyway.

The thermostat is a 180 degree; I don't like anything lower because I'm cold natured and I freeze my *** off in the winter.

I have a couple of more questions if your patience with my situation is still intact.

1. Could a intake manifold gasket cause the same problem? I have had it off and on several times and that is a possibility.

2. Since it seems that my engine is running rich, why is my oxygen sensor not correcting? I have had a problem keeping my headers tight. Could an exhaust leak at the head cause the o2 sensor to be "fooled"?

I think your patience would be a little worn . . . I'm glad to help. It gets frustrating when you've had the motor apart so many times. Hang in there.

I'm not sure about the intake gasket, it could definately cause some problems if leaking. I always replace mine every time I take my manifold off.

I'm not an expert on EFI, but that 180* thermostat could be a problem. As I mention above, if the computer thinks that the car is still cold, the computer keeps the car in "open loop" meaning the O2 sensor is ignored and the mixture is kept rich. I thought that most TPI cars came with a 195* thermostat in them. You may want to check with a dealer to find out for sure what thermostat to use. You could pop the factory one in if you take your manifold off to replace the gasket.

The other possibility is that there is a component failure in the computer system or a wiring problem somewhere causing the computer to go into "limp home mode". This would be very difficult to help you T/S on line, but might be your next route.

An exhaust leak probably would not cause a problem. Did you weld the sensor into a set of headers or are you using stock exhaust? The O2 sensor in the wrong spot could cause a problem.

Do you have any error codes at all? It seems that the computer would call out some error if the motor was that rich.

[This message has been edited by Eric68 (edited 09-09-2001).]

The idea with your cam doesnt sound shabby,A 383 uses a small base circle cam and tpis like alot of lobe seperation,I think i would get more info on this from a reliable fuel injection supplier!

Thanks for all the replies, guys.

When I said I had a 180 degree thermostat, I only assumed that's what it was. I actually took what they gave me at advanced auto parts which was looked up according to my application. That being the case, I probably do have a 195 degree thermostat.

I do beleive that the computer goes into closed loop, because I occasionally get a code for a vehicle speed sensor failure (I can't remember the number) when I drive the car. This is because I am having a little trouble marrying the t56 sending unit to the t-5 designed computer system. But that's another story.

On the small-base-circle cam issue, I actually used a standard sized cam and had the connecting rods trimmed for clearance. I submitted the lobe separation angle (112 degrees) to Fastchip, along with all the other information, and had a chip custom made. It works pretty good too; before all these problems arose, the car ran great!

Anyway, I'm still putting the finishing touches on the engine from the partial tear-down. I'm trying to be extra careful with all the gaskets and torque numbers so that I can eliminate them from consideration should the problem persist.

As always, thanks a ton for all of your help. Maybe one day I can return the favor to you guys somehow.

I almost forgot. I am using hooker headers which already had the o2 sensor port. It is located on the collector portion of the header on the driver side.

I would consider reverting back to exhaust manifolds if you guys think it is a good idea. For some reason, the o2 sensor is not doing its job, and that could be it.

Losing a few horsepower is better than the car setting in my garage for eternity.

The collector seems too far away from the exhaust port to me (unless you have shorty headers maybe). I seem to recall seeing them usually mounted in a primary tube closer to the head. Maybe an exhaust shop would know exactly where the O2 sensor should go - if it's way off maybe they could just weld in another fitting and you could keep the headers (a cheap $20 job maybe?).

I think that O2 sensors work off of temperature, but there may be more to it. The hotter the temp the leaner the mixture I think. Starting to get out of my area of experience here. I hate to say it, but it may be time to get a hotrod-friendly dealer to help you out.

O2 sensors do what they say. The measure the amount of or lack of O2 in the exhaust system. The further away from the head only makes it take longer to warm up but you have a heated one so your ok there.

Now what color was the tip of the old O2 that you replaced? Greenish or dark gray can mean coolant in the exhaust. Did you use sensor safe RTV when you put the engine together? Silcone and lead will ruin an O2.

You could have coolant leaks in other spots on the engine, like throttle body coolant passage to name one.

Have you checked the fuel pressure regulator? If its bad the car could run to rich just from having to much fuel pressure.

As long as you had a chip made to the specs of your cam and engine size than the computer should have no probs. as long as evey sensor is working fine.

After you put your engine back together triple check every thing like connectors and torque specs. Ive done a few engines on these cars and they never get easier to do.

------------------
70 camaro 307 (350soon) /350th

As a matter of fact, the headers are shorty headers. Its all I could get to fit in the darn thing. Almost defeats the purpose of having headers, which reinforces my thoughts on going with manifolds instead.

Good point on the throttle body. I reused a lot of parts on the throttle body, specifically the "lower assembly" which I think flows some coolant. I will check it right away, I never thought of that.

One more note that might give you guys some ideas: Some time ago I bought a mixture guage from Autometer and wired it into the oxygen sensor. When I did, the indicator just pegged lean and pegged rich, over and over, so fast you could hardly see it. This was after the engine was warmed up.

I am on my third o2 sensor. I will take a look at the ones I took out and get back to you on their appearance (I had the same problem then, too, which is why I kept replacing them).

I tried an adjustable pressure regulator with no luck in fixing the problem. I bought a new stock fpr and put on there, because I did'nt really like the adjustable one. Anyway, none of this seemed to help or hurt the problem. I kinda feel that if it was that, I would get a code for rich mixture, which I have never gotten.

I've got quite a mess here, obviously, and its awfully good of you guys to help me out. I'd be lying if I said I didn't enjoy tinkering with the engine, anyway. Especially since you guys have given me some new things to try.

Maybe I won't have to change my username to 383-4bbl after all.

The guage pegs rich and lean over and over again because the O2 works like a generator. The amount of O2 in the exhaust detrimines if the O2 will generate a higher voltage or lower voltage (.25-.9 volts is the range generated). What the computer does is run a little rich than a little lean and this averages out to a perfect mixture in theory. The faster it switches the better the O2.



------------------
70 camaro 307 (350soon) /350th

Guess that guage was an unwise purchase then.

I have a new theory concerning the throttle body. Underneath it there is mounted a coolant apparatus of some sort which flows coolant to (and I assume through) the throttle body. There is a possibility that the gasket has failed, which it seems like would allow coolant to enter the air coming through the throttle body.

I am replacing the gaskets, anyway, since I have already took it apart.

Does this theory sound any good to you guys? Obviously, I am now treating this as a problem with multiple causes.

I think that use to be a prob. on early tpi GM engines.

With to much coolant entering the intake could make the car run bad but the combustion cambers should have been clean. Water and antifreeze usually do a good job of steam cleaning.




------------------
70 camaro 307 (350soon) /350th

Still no news as I am taking my time rebuilding the engine. I'm almost finished; I'll let you guys know how it goes.

I have changed every gasket, double checked all the torque settings, and generally been careful with everything.

The idea that the throttle body was leaking coolant does not seem to be correct. I haven't really found anything wrong, but maybe the problem wasn't obvious and the new gaskets will fix it, anyway.

Thanks again for all your help.

Just got the car back running, and I'm afraid the problem persists. I have another observation to pass on, however.

I painted the headers blue prior to re-installing them. When I cranked the car, all of my pipes slowly turned a brownish color except for the #1 cylinder pipe. It remained perfectly blue. I put my finger on it and noticed it was not hot, while the others quickly heated up and melted the paint.

So, obviously, I'm not getting anything out of my #1 cylinder. I replaced the plug, checked the plug wire & connections, and felt the injector pulsing. They are new injectors, so I am confident that they are ok, anyway.

This leads me, of course, to a couple of questions:

1. The car is still smoking heavily, and the odor is still tear-jerking strong. However, I have no anti-freeze in the car, only water. I am getting a lot of water out the exhaust, enough to cause a dark spot on the gravel, anyway. Is this water in the cylinder(s), or could this be condensation and the odor be normal?

2. Since the o2 sensor is on the same side as the #1 cylinder, could this cylinder not firing create a problem for the sensor, thus fooling the car into running rich? (assuming that it is running rich)

I still have no error codes, and, other than the smoke, seems to be running smooth. I drove it down the road and had no problems at all except it seemed to want to die when I let off the gas with the clutch in. I may not have the idle set correctly, however.

As always, any help would be greatly appreciated.

I know there is an electrical/ diode type check for the coolant sensor. Could also fool the computer into false rich/lean readings, but wouldnt explain that #1 cylinder not heating up.

Just another update. Concerning the #1 cylinder not firing, I have checked the following:

Spark plug--OK
Spark plug wire--OK
Distributor--OK
Valvetrain--OK
Obstructions--OK

The engine is still running smooth, It almost doesn't seem like there is a problem at all. No error codes, no knocks or sputtering. Just no heat (at all) coming from the #1 header pipe.

Again, any advice would be greatly appreciated.

Myself, I would do a compression check at least on the #1 bank to see whats up.

Ok time for me throw a wrench into this picture.

In my 68 I ran into a carb problem that gave some of the same signs you are seeing. So it made me wonder.

What happened was my Holley (recently rebuilt) started leaking on the secondary side. The car would start but it blow whitish smoke (Not solid white like a coolant leak) and there was a god-awful smell. It was bad enough to make my eyes sting and it was hard to breathe. Now it also blew a liquid out of the exhaust that had a black color to it. I think back to it now and I'm wondering if it was excess gas that was taking the soot out of the exhaust and blowing it out.

Anyway we found that the secondary was leaking and flooding out the engine.

I'm thinking if #1 isn't firing if that gas is getting into the exhaust and giving you the smell, color and the rich readings. Again, just a thought.

Now I know this probably isn't the ASE way to test but if you put the #1 plug in the plug boot and have someone try to just turn the engine over (don't try to start, just crank it) do you get a spark on the plug?

I see that you tested everything, but did you test them together (if that makes any sense)?

Now I’m extremely curious on why your new engine isn’t firing on the #1.

This might not of helped any, but hopefully it might give some idea.

Thanks, for your time.

Finally, some progress! I swapped the #1 and #3 fuel injectors; and the #1 started firing and the #3 stopped firing.

Also, this is the side that the O2 sensor is on. Since the cylinder was pumping air, I am thinking that the O2 sensor was fooled into thinking the car was running lean. The computer, in turn, added fuel to compensate, causing all of the other cylinders to run rich. Thus, the smoke.

I won't know for sure until I replace the injector, but I think we did it.

Thanks again for all your help; Even the theories that did not pan out gave me peace of mind, something I sorely needed.

You guys are the best, and this website has done for me what no mechanic could do--give me answers!

I have continued this topic under the name: "383 tpi running rich: continued..."

This way, those who are interested do not have to read so much to get caught up. All of your feedback has been great, and I appreciate it. Please continued to give your input.

Disregard the last message. It was suggested to me by the administrator to keep everything on one thread. This has been a wonderful website, and I won't dare go against the admin.

Back to the car... and the problem. I FINALLY got the replacement in for the defective fuel injector. I installed it and, after a few other odd and end tasks, got the engine back to running.

Unfortunately, the same problem is back. Running rich with no computer code. It is smoking, but not "billowing" smoke. I am quite sure it is running rich; smell is very strong and its not oil or steam. I'm sure this time.

Its not a gasket, they were all good before (with the same problem), changed them all anyway. (head and intake manifold)

Here is a itemized summary of what's going on:

Smoking from running rich
No error codes at all
Oxygen sensor OK (on 3rd one, tried heated)
Backfires when let off (popcorn--normal?)
Good power, smooth running, especially at WOT
Rough idle, but using strong cam
Smoke worst at idle, low rpm
Puff at WOT, then NO SMOKE until I let off
O2 sensor driver's side ONLY
Changed air/water temp sensor & map sensor
Speed-Density system, no MAF sensor
Aftermarket custom-programmed chip
Cam is SLP "computer friendly"
Started 2 days (50 miles) after initial start
Ran perfectly (and smoke free) before that
Checked (& changed) head & int. man. gaskets
Cyls and valves were sooted up good & black
Tried milder computer cam--No help
Replaced entire distributor--No help
Replaced plugs, wires, & coil--No help
Replaced all injectors--No help
Replaced failed injector in new set--No help
Checked valvetrain during cam replacement-OK
No evidence of any internal damage
New fuel pressure regulator (3rd one)
Friend says vacuum leak from listening to exh
Many vac parts carryover from old engine
Plenty of exh condensation, but not abnormal

I'm sure I'll think of plenty more. Hope this isn't "information overload" but I was hoping there was something in there that would set off a light bulb for one of you guys.

By the way, I changed my oil pan gasket this weekend, without the resources to lift the engine. And I mean the whole 4-day weekend (Thanksgiving) for one gasket! Damn those strokers with the deep oil pans! Damn those gm engineers who only gave me 1/4 inch to work with! I compare it to trying to put a 8-armed t-shirt on a moving spider. Screw those guys who changed out their own faucet!

Anyway, thanks in advance for you continuing help.

Geeez, you've been after this problem for quite a while now. I had an idea though, don't know if it would help.

Could you get access to a pyrometer or infrared temp gauge? Maybe you could "shoot each header primary a couple inches back from the head and look for temperature vaiations between cylinders. this might be a tip off if one or more cylinders are not firing correctly (too cold or too hot). Too lean would be very hot, too rich would be on the cool side.

Hang in there man - I thought you had it nailed when you replaced the bad fuel injector.

Thanks, and me too. I think I know where I can get my hands on one. I'll try that and report back.

I cranked the car today and tried unplugging the vac hose to the fuel pressure regulator and then blocking that line (something I read). This is supposed to trigger a rich condition severe enough to give me an error code. I did it and NO CODE. As a matter of fact, nothing really seemed to change as far as the way the car ran.

Could this mean that I have a bad o2 sensor? I've replaced it twice, and don't really think that it is the problem. Or do you think this is a bogus test?

Also, the car sits on 195 degrees pretty good. It should be in closed loop mode. Any way to make sure that it is? In open loop, it won't correct for the mixture, or so I've been told. Maybe I'm in open loop.

Thanks in advance for your help.

Youll need a scanner to see what the computer is up to. Use the scanner to read the live data as the car is running. You should look for a few things- 1.That the O2 sensor is switching 2.That the map sensor and TPS are within specs 3.See what the fuel trim is at 4.Last make sure the computer is going into closed loop. Let me know what the numbers are from the scanner and I could see if I see anything thats out of norm.

------------------
70 camaro 307 (350soon) /350th

Thanks. Any way to check to see if it is in closed loop without spending money?

I may be on the right track with the "open loop" issue. I unplugged the oxygen sensor with the car warmed up and got no error code. Apparently, the computer is staying in open loop. Does anyone have any idea what could be causing this?

Look at the coolant temp sensor for the computer closely. Only the engine temp and 02 can keep an engine in open loop. If the engine never gets to operating temp it could also stay in closed. Also a defective TPS showing wide open throttle at idle can keep an engine in closed loop.

------------------
70 camaro 307 (350soon) /350th

I'm gonna say something that will probably **** you off. I hope it doesnt! stop screwiong around and take it to a pro! for the money and time you lost you cauld have had it diagnosed and repaired. If there were no problems before you did anything It should be easy to trace. I have found the more complicated a problem seems the more times it ends up being something silly. We have a slogan in the diagnostic trade" BACK TO BASICS". By the way are you sure you didnt install the prom backwards? Your computer is not working!!!!!!!

First to Milan, I would tell myself the same thing, but I have actually taken it to several mechanics and had it "hooked up" several times. They all tell me they can't find anything wrong. I even had one to tell me that its "burning oil" and that was the only problem.

They are somewhat correct in that the computer is not seeing anything wrong (it is NOT, however, burning oil and this I am sure of). I can't afford to keep paying these guys for nothing.

You could say that I have a lack of options in this regard. I live in a small town, and can't really take it a long distance to have it looked at given its running condition. I'm STUCK.

Anyway, I enjoy talking to guys who have been there, just like me. I am hoping that as long as this thread is still "burning", there is a chance that someone who knows more than me can figure it out.

Anyway, thanks for the advice, and you are absolutely correct. Unfortunately, your solution is not an option for me right now.

To Joekool1234567, By the time you read this I will already be checking the temp sensors and o2 sensor. I'll let you know.

Thanks guys.

hang in there 383tpi, sit back, take a few deep breaths, inhale about a twelve pack, let that wear off and then look at it from a different perspective. it is probabily something you wouldn't even consider related to the problem. in about your first post you mentioned that you had been changing the oil because you suspected it was contaminated by fuel because of its odor. a simple test for that is to take a small sample of the oil and strike a match to it. if it burns, you have gas in the oil. you might have a gasket leaking around your oil pump that is letting fuel in. just a thought

383, when they "hooked" the car up did they get any data, and did they try set and clear any codes? If you dont know the answer ask the techs. That is part of what you paid for.
I refuse to believe that if the computer is working properly, that you are having this many problems and the system is unable to capture a single trouble code.

I agree with milan that if you take it to a mechanic I would have them show me the spec and then show me what my computer reads. Some thing has to be off or the car would run good. Theres no way a car will run bad and be perfect on the scanner. The littlest things will make all the numbers change in the live data on the scanner.

Just stay with it and soon or later youll get this one solved.

------------------
70 camaro 307 (350soon) /350th

You guys are right, I got hosed pretty good. When I asked the guy what the fuel trim numbers looked like, they looked at me like I just asked them what was the formula for calculating an earth orbiting trajectory.

Again, I live in a small town. We don't know much 'round here. Thanks for your patience.

Oh yeah, Joekool gave me an idea on the TPS. I remember getting an error code on the TPS before everything went to pot. I checked it and it checked ok (with a voltmeter), but it may have been an intermittent problem at the time and now is a permanent problem.

I never thought anything else about it because I never got another code. BUT, I may have been staying in open loop because of the TPS, and would not get a code.

Sound reasonable? Anyway, I found one pretty cheap so I'm going to give it a try. If this doesn't work, its back to the mechanic, maybe with better luck this time.

If the TPS doesnt fix your problem then try to force a code. I was rereading some of this post and noticed that you said you unplugged the 02 and got no code. Just unplug the vacuum line from the map sensor or unplug the MAF, which ever one your engine has, and try to force a code. The check engine light should come on too. Just want to see if the computer is working right.

Does the check engine light come on when you have the key in the run postion?

------------------
70 camaro 307 (350soon) /350th

The light does come on when I turn on the ignition, before I crank it.

I tried unplugging the vac line to the MAP sensor. It sputtered and died. I tried to keep it fired long enough to get a light, but never got one. I then tried unplugging the MAP sensor, and got a light, and the car sputtered and died again.

I read the codes and got a 22 and a 34. The 22 was a TPS problem, but I got that light earlier while conducting a different "experiment". The 34 is a low voltage MAP sensor, which figures from unplugging it. Those were the only codes.

Again, I get no code from unplugging the oxygen sensor. I put a new one in yesterday (again), and checked the continuity in the lead from the sensor all the way back to just before the ECM. It checked out ok. I know you are not supposed to use a voltmeter on an oxygen sensor, but what did I have to lose? Also, when the car was warm, I checked to see if I was getting any voltage from the o2 sensor lead. I was, but my voltmeter doesn't register low enough for me to take a reading. All I know is the needle moved indicating something was going on.

I know it is running rich; when I pulled the heads, everything was sooted up. The o2 sensor I removed yesterday was also good and black. I checked the voltage on the TPS, and got about 0.6 volts at idle. You can loosen it and move it a little and retighten, so I did this to get 0.54 volts, which should be perfect. I then disconnected the battery and reconnected to clear everything, and tried again. Same problem.

I've got a new TPS sensor on the way. If that doesn't work, I'm going to talk to a mechanic, and try to be VERY SPECIFIC about what I need from him. Hopefully I will have better luck this time. I am hoping the fuel trim numbers will reveal something.

If that doesn't work, I'm going to talk to the chip maker again. But, since the car started out running ok, I doubt if that is the problem. The computer seems to be working normally, except for the rich condition.

Is there a module or something that corrects the mixture? I can't figure it out. I've been through the whole engine, the sensors, and the computer.

WHY DOESN'T THE COMPUTER SEE IT!?!?

One more note, I've been noticing a lot of water coming out the exhaust. Not gallons or anything, but enough to wet the gravel underneath the exhaust pipes. It's not coolant, because I'm running pure anti-freeze, and whats coming out of the pipes is colorless and odorless. I'm quite sure its water. Is this normal?

Thanks again for all your help.

Try and get the engine up to operating temp and hold the RPM at 2500. See if you can get into closed loop or at least trigger the engine light. I want to see if some how the 02 is not getting hot enough because the 02 has to get hot and stay hot to work properly.

First you have to get the computer to work at controlling the engine and to get the thing to know thats its running too rich. Only in closed loop will the computer even try to control the engine

Once the computer is in on this than you can rule it out and look for possible fuel leaks or mechanical problems. Right now I suspect computer problem(s) because of the fact that it doesnt go into closed loop or try to go in to closed loop.

The water is normal from the exhaust if it had a blown head gasket you would have to add coolant every time you ran the engine.

------------------
70 camaro 307 (350soon) /350th

Thanks for setting my mind at ease concerning the water. I am not losing any oil or coolant.

I will try heating the o2 sensor up using the method you suggested. Keep in mind that I have tried a heated o2 sensor. Of course, I can't rule out the possibility that I had it wired incorrectly.

I'll let you know how it goes. Thanks again.

That didn't work. Just kept smoking after running it at 2500 rpm for I guess several minutes, until the temp guage started getting above 220. The headers were glowing a little, so I'm sure the o2 sensor was good and hot.

I need to get a voltage reading from the oxygen sensor. I'm going to try and borrow a digital voltmeter from someone to get a detailed reading, just to be sure that it is working.

If the voltage is indicating a stoich condition, could I assume that there is a problem on the passenger side of the engine, since the o2 sensor is on the driver's side? I've even thought about welding an o2 sensor fitting on the other header and trying the o2 sensor in it. Also, I considered swapping the injectors and plugs to see if I could transfer the problem to where the oxygen sensor could pick it up. Assuming that one of these is the problem.

Any of these ideas make sense? Thanks again.

Try to force a lean condition to see if the engine will run better. Unplug vacuum lines even the one to the booster if you have too. I suspect you have either a computer thats gone wako or a real bad fuel leak on one or more of your injectors that the computer can not see.



------------------
70 camaro 307 (350soon) /350th

I'd keep looking real close at that computer. If you couldn't force an error code by unplugging a sensor than you definately have a computer prob.

One thing that I've seen at work with automated machinery controllers is that if any input or output to/from the computer gets shorted to ground it can lock up the computer. Especially the inputs.

Could you have a wire bundle that got pinched or cut when you swapped your motor? Could you have a shorted fuel injector? You mentioned that you already confirmed one was bad earlier.

Can you verify that the computer advances/retards timing as it is supposed to? I'm curious to see what functions the computer is controlling if any at all.

Hang in there man. I'm still following this thread and will chime in from time to time if I can think of anything that will help.

Eric

ok i have read and re-read this thread now go back to Basics as far as the computer is concerned, Remember the term GIGO ( Garbage in Garbage out ) If I remember correctly you had the eprom specificly built for the motor, Are you sure you didnt forget anything or that the builder didnt forget anything ?, If Thats not the case see it this way what controls idle mixture, air intake, and Fuel delivery ? Ummm computer correct ? take a hard look at the 2 items and see where the problem may lie.

383tpi, I agree with Rsmith1969 I think that he's pretty close to nailing this thing! I thought that I read somewhere in the post that you tried to force and error code and couldn't get one...? I'd say that the ECM may be a gonner! The smoke thing still troubles me though I can't quite zero in on that one. What sounded like a intake leaking coolant into a cylinder at first but now I'm not so sure! I would chase after the ECM troubles first and see if the rest doesn't work itself out in the process. Keep us informed as to what you find!

Good luck



------------------
1967 Prostreet Camaro
402cid BBC TH 400 w/4,500 stall 4:56 gears,narrowed and tubbed... Well almost
http://www.visionworks-usa.com/camaro

Thanks to Eric68 for hanging in there with me, and to you other guys for your input as well.

The injector leak seems very possible. But, it seems to me that if the o2 sensor looks like charcoal, it should be picking it up. That sort of messes up my theory that changing injectors/plugs from side to side might reveal something.

Since I have put 4 oxygen sensors in the thing, I am starting to be interested in the theory that the computer is wacko. If you think about it and go back through everything that has been done, we can almost rule out everything else.

Since the o2 sensor is good, and its connection is good, it should be telling my computer "hey dude, I'm suffocating down here". Since every o2 sensor I have pulled out is sooted up, I think the o2 sensor is screaming RICH but the computer is ignoring it (instead of not hearing it).

I do have one question. How long (typically) should it take for my ecm to go into closed loop. If the car is dead cold, the smoking starts about one minute after I crank it. Could this be at the same moment that closed loop is achieved, or does it take longer for the o2 sensor to heat. Actually thats 3 questions, but you guys see where I'm going.

I'm going to inspect the wiring harness to make sure I'm not grounded or broken somewhere, like Rsmith1969 suggested, to try and rule it out.

Thanks again for all your help.

See in order for your computer to go into closed loop in needs three things. One is the coolant temp sensor. When it reaches a certain temp it tells the computer that the engine is warm enough for closed loop. Second and most important is the 02 which is used to control the mixture. With out the 02 the computer can only guess at how much fuel to add so thats why you need a warm 02 to get in to closed loop. Third is a timer in the computer that tells the computer to check for a warm engine and a switching 02 sensor (which means the 02 is working).

Now if the car never enters closed loop the timer is suposed to tell the computer to turn on the engine light. The only way to tell if the computer is in closed loop or open loop is by using a scanner. You could have to sevral things happening here. One is the computer is wako, something that rarely happens but could. Second is the computer is confused or not calibrayed right. Third you have a fuel leak that is not bad enough to trigger the engine light but makes the engine run bad.

Now knowing older GM computers had broad tolerances so that a car had to almost be not running before a code would set and the fact that you have an after market prom chip might make those tolerances even wider. Try and call the manifacture of the prom chip, tell them what is happening and try to get a new one.

Once you rule that out than look into a fuel leak. After you have rechecked every thing and it still does the same thing than I say try a new computer. 99.9% of the time its not the computer at fault, thats why I have a hard time beleaving that the computer could be at fault. Plus they cost alot of money too.


------------------
70 camaro 307 (350soon) /350th

You don't still have your original PROM chip do you? It might be worth a try to plug it back in and see what happens - bad PROM chip maybe?

I wonder if I get a plaque or something now that my reply count is past 50. I guess I need to be giving plaques instead of receiving them.

I did try my old prom, but since I have so many "unwelcome guests" on my engine, I got an engine light pretty quick.

To joekool, I see your point on the closed loop situation, I realize now that the computer MUST be entering closed loop. And also good advice on the chip being the problem. I have talked to fastchip and they are going to check it out. I recommend those guys, they are professionals and have their act together. Like I said before, when the car was running, it ran like hell with no problems, which is as much a credit to them as anybody.

I'll let you guys know what I find out about the chip. I imagine that the car will be out of commission for a while, so have a nice holiday if I don't speak to you guys before then. And thanks once again.

I think we may be on to something here. Old PROM = check engine light, new PROM = runs rich and cannot force an error code. I bet that new PROM is dead, maybe erased / blank. If you were to put a blank or damaged PROM in, the engine should run in "limp home mode" I believe - timing is retarded, and the fuel curve is RICH. This is by design, for safety to prevent detonation etc. You are supposed to get a check engine light in this mode though and aparently you are not. I bet it's a chip problem though.

Got the computer chip back today. They said it was ok, but went ahead and put the programming on a new chip and sent that one back to me.

I tried the chip and still have the same problem. I let the exhaust blow out onto a clean rag to see what the residue buildup would look like. But, even after a few minutes, the rag looked perfectly clean, except for some water from condensation.

This brings me to some questions of course. First of all, would this "rag test" reveal anything even if it was running rich?

Also, the smoke is a "lingering" smoke that builds quite a cloud when there is no wind. It is not an evaporating smoke like burning coolant might show. It will burn the hell out of your eyes, though. Any chance that this smoke could be normal?

Again, when I first crank it (cold), there is no smoke at all. Then about 2 or 3 minutes later, there is a lot of smoke, like somebody threw a switch or something. It happens well before the thermostat opens, just to eliminate any burning coolant theories.

I drove it down the road, and got a lot of "popcorn" when I let out of the gas (keep in mind that I have a manual tranny, headers, and no cats). Also, it wants to die at a dead stop. Don't know if this is related or not, just worth mentioning.

I'm running a pretty strong cam, and about 11 to 1 compression. Could this be the nature of the beast?

How does the car feel when you drive it? Try making a small vacuum leak and then drive the car and see if it drives better. If it runs better than some how your engine is running to rich. If it runs worse than it might be that the cam needs to run rich at idle to keep runnig good.

------------------
70 camaro 307 (350soon) /350th

Wow, been awhile since I've been to this site, anyways...

Seems you've been at this for quite some time.

Let me ask you a few questions.

What are the cam specs?
Whats the intake vacuum at idle?
What's the base timing set at (EST Bypass line disconnected?)
What's the timing at idle with the EST line connected?
What EPROM are you using?

You can monitor the rich/lean and open/closed loop operation via jumpering A and B on the ALDL while the engine is running, I forget when to do it, haven't had a need to for years since I gota scantool, but I'll see if I can dig out the info for you.

My initial "guess" is too much cam, too low vacuum playing a bit of heck with the MAP sensor and throttle agle at idle...SD setups (without programming) don't take to too much cam, I'm guessing that with you running 11:1CR your .050 duration #'s are in the 220-230 range and the stock and "off the shelf" EPROMs won't really be able to handle it.

Jeez, what a string. I laughed. I cried. I gave it a 10. I was just hoping the saga would end for Christmas!

I'm no genius with PROMs and advanced configurations, but I had a couple of thoughts after reading through the story....I'll let the pros with the scanners and the cam timing charts tell me where I'm wrong.

1. I don't think you are burning any coolant. The cloud would be white and you would be topping off like a mutha after all of your test runs. Let's not worry about that.

2. If the thing ran good for "a couple of days" as you state before the problem started, then a simple man like me figures that your PROM IS compatible with your setup, just that something went wrong.... Especially if the manufacturer says the chip is bueno.

2 1/2. I'm gonna start an O2 sensor fund for you. If that thing is putting out the spiky volts that you mentioned, I think it is working fine, maybe the computer is just not able to compensate for the problem (oil leak/fuel leak??). Quit dickin with it.

3. If you pulled the heads a while back and EVERYTHING is sooty...you're running rich or sucking some oil in somewhere. It takes a good bit longer to notice that you need to top off the oil...and didn't you say one of your mechanics (without the slide rule and scanner...lol) suggested an oil leak? I'm not sure how the O2 sensors handle burnt oil. Also that might account for the nasty smell. Running rich shouldn't be that pungent. I haven't done it, but can't you jam a cheapo mix detector up the tailpipe just to confirm the mix to see if you are stoichiometric (ala a smog check)? This would certainly clear up the guesswork and possibly rule out the oil leak if it is way rich.

4. Not to talk you into pulling heads again, but just thought about your earlier statement about some of the bolts being a little loose on first check.... With 11:1 and aluminum, those things should be torqued to spec, or you really have alot of leakage risk.

5. (someone may have reasons this one is bogus, but...) Have you considered trying a hotter plug? If things are really fouled up, you may just be missing too much, especially if you are still pulling plugs and finding them well fouled. Maybe your first couple of days of running went well before they got loaded up? I forget if this was looked at earlier in the string.

A couple of things to think about other than the computer, which I don't know anything about.... I find the lack of error codes surprising, but the "wide tolerances" theory fits. I'd look elsewhere.

Lets wrap this up b4 Christmas!

Good luck / Good tidings,

Jeff

OK - read an article in the January Chevy high Performance about injector sizing. I don't recall if you have the original injectors or not BUT if you do then your software could be causing the injectors to exceed their designed duty cycle, normally 85 - 90% max I believe. if you exceed their duty cycle (trying to make the engine run rich enough compensating for more displacement) then possibly you are killing injectors and they are sticking open, closed etc and fooling the computer with bogus O2 sensor feedback. If I recall the article works you through the formula and a 36# is about right for a 400HP engine I believe.

Just a thought.

Thanks for all the info, guys. That's why I love this site.

I ran the car again, and it seems that the problem has somehow improved since the last time. The smoking is considerably less, I guess the new chip needed time to make the necessary adjustments.

There is still some smoke, however. The smoke is now white, and I am getting a lot of water out the tailpipe. It is not coolant (still), the level is fine and I am not getting an anti-freeze odor. I am not burning oil and never have been, judging both from the oil level and the exhaust odor.

Also, no error codes, but never had any. I might can attribute the car dying at throttle down to a bad throttle adjustment. I have been tinkering with it, so I will see if I can fix that. My idle is set at 800 rpm (stock), and that may be too low for a strong cam anyway.

As for the question concerning the chip, The chip is custom programmed to my engine specs, and did run good at first, so I really don't think that is the problem.

I like the idea of a hotter plug. I may try split-fire plugs just to be sure that I am getting a complete burn.

Anyway, you guys let me know if things look better concerning the info I am giving. I know that the higher the compression, the higher the condensation. That could account for the rest of the smoke.

But, you guys know better than me, so what do you think?

Thanks again.

Almost forgot, the injectors are 24#, which should be more than enough since I am using stock tpi with its inherent airflow restrictions. I actually had this size suggested to me by the guys at TPIS.

The cam is 223/230, .501/.510, and is designed to work with computer controlled cars (SLP brand).

I set the timing at 6 degrees BTDC, with the wire disconnected. I have not checked it after reconnecting. The car drives good, and I get a lot less smoke at higher throttle.

Hope this helps.

Almost forgot, again, I am OCCASIONALLY getting some surging at idle. This could further validate the injector theory. When one "fails" somehow, the computer may be having a hard time getting everything back to stoich, and thus the surging rpms. It must get it right somehow, though, because I have never got an error code, and the surging only lasts for a few seconds.

OK - your 24# injectors will support approximately 307HP according to the formula:

HP = (lb/hr flow x 8 injectors x .8)/.5 brake-specific fuel consumption

That is using an 80% duty cycle and assumes 43.5 psi fuel pressure (the standard pressure injectors are rated at by manufacturers). I don't believe intake restriction would have any affect other than the fact that it will limit total horsepower because any give HP requires a specific amount of fuel and air in the correct ratio regardless of pressure drops in the intake path. A restrictive intake would also be a mismatch for your larger cam.

If your engine significantly exceeds 307 HP your duty cycle WILL become excessive at WOT. 400HP would require a 104% duty cycle (impossible) at 43.5 psi if you work the formula backwards using algebra. You can definately cause some injector problems if you exceed an injector's rated duty cycle.

Just my theory. But is based on info from the February "Chevy High Performance" the article is titled "Easy EFI Part 2" see pages 88 - 95, especially injector sizing on page 94.

Perhaps raising fuel pressure would reduce injector duty cycle and help this problem if larger injectors are out of the question.

Good tip. I wonder if the guys at tpis were just trying to unload a bad selling item. I didn't buy from them, anyway, just took their advice and got the injectors at summit.

I am eventually going to buy new injectors, anyway. I bought Accel brand, and have already had one go bad after about 3 hours of run time, mostly at idle. They were the cheapest, and I'm broke, so that's what I got. When I upgrade, I may go with a larger size, and have the chip updated.

I was thinking of having the idle rpms adjusted on the chip anyway. I talked to a couple of gearheads I know, and they say that 800rpm is to low for that strong of a cam. They also say that this could be "trapping" the exhaust in the cylinders, so when the exhaust comes out, it is "denser" than usual. It would also account for the crappy idle, and explain why it runs excellent at high rpms and WOT, just not at idle.

Does any of this make sense to you?

Waz up from Crossville. A freind had similar symptoms and replaced everything it wound up being a bad EGR solenoid and valve car idled rough and would die during deceleration got a haynes book @ autozone on fuel injection and got educated we did a few vacum test and found the bad solenoid and egr valve engine always ran sort of cool to us but found valve stuck half open and replaced it runs good for a stock rebuild. Good luck!

I think you are on the right track with the idle being too low, especially if the quality is crappy. If you're idling for a long time troubleshooting, and it's misfiring alot, yeah its gonna get rich/sooty. seems like a cheap fix??

I read this whole thread. Tell me that it doesn't end like this...

-Mooky

me to. Got to know what he found out. Please!

find out ne thing yet??

ATF also burns white.