Please help,Engine stalls and idles rough when cold. - Team Camaro Tech
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post #1 of 33 (permalink) Old Jan 2nd, 01, 03:12 AM Thread Starter
 
Join Date: Jan 2001
Location: Lakeland,FL USA
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Unhappy

I have a 1988 Chevy Camaro with a 350 Engine and Throttle body fuel injection.

Recent work done: Rebuilt throttle body, replaced egr valve, replaced IAC, replaced TPS, replaced MAP, replaced plugs and wires, replaced fuel filter,replaced ignition module,and replaced pcv.

Past mods and repairs: replaced fuel pump, replaced alternator, replaced 305 with 350, installed MSD ignition, installed k&n filter, replaced muffler,replaced O2 sensor, replaced rotor and cap, installed superchip.

Two days ago a guy from a chevy dealer hooked up a computer to the car and all he could tell me was that he believed the ECM was bad. I installed a different ECM and the same problems occured. He also said that he was getting readings from the EST.


Problems: When the car is cold, it stalls often until warm, idling is very rough, acceleration is rough, almost doesn't accelerate until you find the right spot in the pedal, once warm the car has a intermittant pulsing idle, jumps from 500rpm to 1500 rpm, and occasionally will stall at a red light. SES light comes on every day now.

Any help with this will be greatly appreciated, I am at wits end with this car. To top it all off, my alarm failed last week and over $1000 in stereo equipment was stolen from me.


Logician



[This message has been edited by Logician (edited 01-02-2001).]
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post #2 of 33 (permalink) Old Jan 4th, 01, 08:47 AM
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Sounds like your running very rich. Are you smelling gas alot? Try taking it for a spin without the air filter. Does this improve things? What kind of computer do you have running? Is it the factory stock chip? If not that could be the problem.

good luck
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post #3 of 33 (permalink) Old Jan 4th, 01, 09:30 AM Thread Starter
 
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Thx for the reply goatjj,

I haven't been smelling gas nor does it make any difference with or without the air cleaner. The problem seems to clear up when the car gets warm. I have the factory computer and factory chip. Any additional ideas would be great.

Thx, Logician

P.S. I think I cleared up the stalling at red lights by disconnecting my MSD.


[This message has been edited by Logician (edited 01-04-2001).]
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post #4 of 33 (permalink) Old Jan 4th, 01, 09:35 AM
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Verify the engine is mechanicaly OK by doing a compression test.

Make shure there is no flat cam or broken valve springs, bad rocker arms etc.

Do you have low vaccum?
David

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post #5 of 33 (permalink) Old Jan 4th, 01, 09:40 AM Thread Starter
 
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David,

If it had a bad part wouldn't the performance be bad while the car was warm also? Once warm it runs good. After reading dozens of posts on the boards it seems that the O2 sensor controls the gas mixture once warm and that explains why it runs good warm. I don't know, I'm a pc tech not a auto tech. I don't know about the vacuum, the computer didn't show any vacuum leaks and I replaced everything I know of that works with vacuum.

Thx, Logician

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post #6 of 33 (permalink) Old Jan 4th, 01, 09:53 AM
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Hmm
Since you seem to run well when warm, It must be your fuel injection. Is the intake working with open air or warm air from the engine. If your running with open air that may be your problem. My camaro ran much better with a new electronic choke on my carb. I know your fuel injected, so maybe a closed thermatic air filter would help. This would cut down on warm up time and give your engine constant heated air to run with. A bad or to large of a cam could also cause a rough ride, but try the air first. It should only take 100 bucks to get.
One more thing! Who did the engine switch? If running with a 350 the cam is bigger. They're a bunch of adjustments to do in order for your car to run smooth.

Happy 2001

[This message has been edited by goatjj (edited 01-04-2001).]
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post #7 of 33 (permalink) Old Jan 4th, 01, 10:25 AM Thread Starter
 
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Goatjj,

About a year and a half ago I did the swap with my dad. We used the old heads, the old cam and pushrods and roller lifters. The car was running fine for the last year. Only for about the last month has it gone to hell. The only thing I can think of that changed was the fact that I ran the gas tank to E twice this past month. Is it possible for these problems to show up this far after the work has been done?

Thx, Logician

Maybe it is a year 2001 bug.

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post #8 of 33 (permalink) Old Jan 4th, 01, 11:03 AM
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If you ran to empty, I bet your injecters are getting cloged. Clean out your fuel lines and check the filter for dirt.
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post #9 of 33 (permalink) Old Jan 5th, 01, 02:10 AM Thread Starter
 
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Goatjj,

Injectors are spraying nicely and I changed the filter Tuesday.

Someone suggested to me that the Pickup Coil in the distributor could be causing this problem. Does anyone agree?

Thx, Logician
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post #10 of 33 (permalink) Old Jan 5th, 01, 07:37 AM
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What code are you receiving from the ECM? If the dealer said it's an ECM error code and you receive the same code with a proven ECM then I would start tracing wires, as it will probably be a shorted wire. This will be a good place to start.

Something else, check the wire to the cold start injector, or the injector itself. From the sound of things it really appears like an over fueling problem. Have you run an ohms test on any of the injectors?

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[This message has been edited by cardude (edited 01-05-2001).]

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post #11 of 33 (permalink) Old Jan 5th, 01, 03:00 PM
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If the dealer tech mentioned something about an EST problem, it may be a bad pickup coil. One easy check is to remove the distributor cap and lightly tug on the wires to the pickup. If they come loose you've found your problem, also check to make sure the connection dont have the green coat of death (corrosion) on them. P.S. Be prepared to replace the pickup before you try (lightly) tugging on the wires. My next question would be have you checked to see what code is being stored since you say the check engine light is on? One other point, have you checked all the engine grounds to make sure that they are clean and tight? Two particular places to check on this model would be at the bellhousing to engine bolt/ground stud, and at the thermostat housing ground stud. Hope this helps.

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post #12 of 33 (permalink) Old Jan 6th, 01, 12:27 PM Thread Starter
 
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I worked on the car today and found out the following: pickup coil tested good, replaced defective fuel pump relay, and found a ground wire on the firewall that was not connected to the engine. The car was running great warm, once I let it cool down it had a pulsing idle and continued to shut off. When I got it warmed back up it ran great again.

I tried to run the codes again but there is a weird problem. The 1 2 1 2 1 2 codes work fine and they are very bright, but when it goes to display the additional codes, the light goes real dim and you can't tell how many flashes it is making. I am suspecting a bad ground to the ecm, first thing tomorrow I am going to check that out in hopes that that is the problem. Any further input is greatly appreciated.

Thx, Logician
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post #13 of 33 (permalink) Old Jan 7th, 01, 01:17 PM Thread Starter
 
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I worked on the car again today. This is becoming a career for me!

Today I changed out the distributor, pickup coil, ignition module and rotor. Same problems.

At this point I am convinced that the fuel pump is going bad.

We sprayed carb. cleaner directly into the TBI while idleing and the car idled smoothly.

My current fuel pump was replaced about two years ago and it was purchased at Discount Auto Parts, I am fairly certain it is under warranty, but I hope to upgrade to a higher performance unit.

Can anyone recommend a better fuel pump that Discount Auto sells?

Any info is greatly appreciated.

Thx in advance. Logician
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post #14 of 33 (permalink) Old Jan 8th, 01, 08:20 AM
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Question? Did the car idle rough and stall before you replaced the ignition coil? If not you may have it wired wrong. Have you checked your compression? When you set your timing,do you use a light? You may be 180* off. How many miles on the engine? You may have a flat cam. Check your intake gasket. If the car idles fine after spraying carb cleaner in to the tbi, it usually means you have an intake gasket leak.

I hope it all comes together.

[This message has been edited by goatjj (edited 01-08-2001).]
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post #15 of 33 (permalink) Old Jan 8th, 01, 09:02 AM Thread Starter
 
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goatjj,

The car did idle rough prior to replacing the ignition coil. I haven't checked compression, I don't have the equipment. I would use a light but my marks are gone, lol. The timing is where it has always been and it didn't run bad two months ago. I ran the tank down to empty twice in a row a couple of months ago, I wonder if the fuel pump is clogged or because it's a cheap dap fuel pump it is just going bad. It should'nt be the gasket because I just changed the TBI gasket 2wks ago and the intake manifold gasket 2yrs ago when we did the engine swap. I have no idea what shape the cam is right now. 2yrs ago it was pretty decent, but remember it is the original cam that came out of the stock 305 engine. If the cam was flat, wouldn't it run poorly while warm too? I really appreciate the help from you guys. As soon as I nail this thing I'm gonna post in detail what fixes it in case the rare chance occurs that someone else has all these problems.


Thx again Logician

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