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Discussion Starter #1
Hey all. I'm having a problem with my '89 L98 IROC. For quite a while now, the motor will turn over when I crank it, but it won't start for a good 10-15 seconds or so. If I crank it for a couple of seconds, stop, and then try again, it usually starts right up. But this is mostly only when it's cold. There is no smoke when it starts up, and it runs great once it's started.

That would lead me to believe that there's an oil pressure problem, but the oil gauge looks good when I turn the key. It Seems to build up normally and won't start even with good pressure - according to the in-car gauge.

Timing is set to 6 BDC, plugs are Bosch Platinums, the pick-up coil and ignition coil have both been replaced in the last year or so, and the wires are brand new. I haven't had a chance to get a hold of a fuel pressure gauge, so I'm not sure where I sit with that.

If anyone has any suggestions, I would greatly appreciate them. Thank you for your time. - John '89 L98
 

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You're on the right track now. I'd replace the fuel filter. Very easily done, takes longer to jack up the car. Precaution when changing filter is the orings at the end of the fuel lines. If they're damaged, they'll leak. So give them a good inspection.

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67 Camaro LS6 454/TH400/12bolt 3.73
1989 TransAm 5.7L WS6 W/all the options
 

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Does the fuel pump run like it should when you turn on the key? Something to check if so - a lot of these FI cars have a thing in the tank hooked to the fuel pump called a Pulsator. Has a diaphragm in it to smooth out fuel flow. This can get a hole or split in it and you lose fuel pressure. Takes a while to build up and bleeds off fast. Need to check the fuel pressure. An old AC gauge will hook up to the pressure tap on the fuel rail.
 

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John, Some of those cars had a 9th injector that was used for start-up and for cold enrichment and it is in the lower part of the intake that is bolted to the engine. I'm not sure what year that they were in, but they did get clogged. Does your engine have an extra fuel line that goes to the back of the engine?

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Leo Paugh
MCC #017
www.clark.net/pub/chevelle/mcc.htm
the bitterness of poor quality remains, long after the sweetness of the low price is forgotten
 

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I had an 89 IROC it had no cold start injector.
Be shure when you try to start the engine to first turn the key to on, then pause, count to four, then try to start.
The fuel pump is turned on by the computer for about three seconds to pressurize the system. If you try to start too soon you are just cranking with no fuel going into the engine because minimum injector firing pressure has not been reached yet.
If you don't hear the fuel pump run, there is a problem.
And keep your foot off the gas pedal of course.
David

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Check my web page for First Gen Camaro suspension info:
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67 RS 327
69 Camaro Vintage Racer
65 Lola T-70 Can Am Vintage Racer
 

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Your fuel pump should operate for 2 seconds when the ignition is turned on.
You can check if it does by having some one turn the key on while you're back near the tank and listen for it or if you have a test light connect it between the fuel pump test terminal and ground. The fuel pump test terminal on your ALDL connector under the instrument panel should be the lower left most terminal as you look at it.
If you don't hear the pump or have no light for 2 seconds, suspect the fuel pump relay.
If the fuel pump relay goes bad the fuel pump will be energized through an oil pressure switch. This means the engine has to be cranked till oil pressure builds enough to close the switch and turn the pump on, 10-15 seconds of cranking sounds a little long although even if the relay was bad.
 

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Discussion Starter #8
All right... Thanks to everyone for the replies so far, I guess I should add a little more to my story. I replaced the fuel pump (and filter) about 6 months ago because I honestly thought that was the problem. It wasn't.

When the key is turned just prior to cranking, I can hear the fuel pump running for its usual 2-3 seconds, although it can sometimes take up to 7-8 seconds. No matter how long I wait after the system pressurizes and before cranking, it does the same thing.

So... I don't think it's the fuel pump, I'm certain it's not the fuel pump relay, (although the symptoms are similar to what a faultly relay would result in), and because GM did away with the 9th injector prior to '89, it can't be the problem. Any other suggestions? Thanks again. - John '89 L98
 

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Okay, so once the engine starts, while it's in open loop operation, the engine idles good.

How does it run once the engine goes into closed loop (operating temp)?? Do you notice any bogging when you floor it?? Erratic idle (hunting)??

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67 Camaro LS6 454/TH400/12bolt 3.73
1989 TransAm 5.7L WS6 W/all the options
 

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Discussion Starter #10
The engine runs fine once it starts. It doesn't matter if it's in open or closed mode. In fact, I just took it out to Cedar Point last week. Everything, as usual, was fine - except for the hard starting. - John '89 L98
 

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I had a similar problem with my 86. I replaced the in-tank fuel pump and it cured the problem. Turns out the pump wasn't holding pressure.

Good luck.....
 

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John, can you have someone hook a scan tool to it while it is cool to check to see if the temp sensor is telling the computer that the engine is cold? If the sensor is telling the computer it is warm, it will be hard to start cause it will be lean.

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Leo Paugh
MCC #017
www.clark.net/pub/chevelle/mcc.htm
the bitterness of poor quality remains, long after the sweetness of the low price is forgotten
 

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Discussion Starter #13
That's a good idea, Chev. I check out as soon as I get back to the garage, which should be tomorrow morning. I'll let you know what happens. In the mean time, any other suggestions? Thanks again. - John '89 L98
 

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Discussion Starter #14
All right... I didn't get a chance to check out the temp sending unit, but I did get my hands on a way to check fuel pressure. Here's what I have:

When I turn the key, pressure is immediately up to 48PSI while the fuel pump is running. While I'm cranking, pressure sets at around 40PSI, and as soon as I shut the car off, pressure starts to quickly drop off.

It takes 8 seconds for it to drop to 30PSI, 15 seconds for it to drop to 20PSI, 33 seconds for it to reach 15PSI, and 58 seconds for it to get down to 10PSI.

It seems a little quick, if you ask me - especially for a new fuel pump, but I'm not sure this is where my problem lies. I say this because I can try to start the car while pressure is anywhere between 50 and 40PSI, and I get no start until I let up and try again.

Argh... Any ideas? Thanks again. - John '89 L98
 

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did you ever change the regulator on it?it might be pushing it straight through. i cant remeber it has been a couple of years since i went to school for cars butt it could be loading the lines with air when you shut it off and let it sit ...if you shut it off will it start right back up? if so i would look at the regulator. you should be able to change the fuel pressure with a vacume pump on the regulator and reading the guage on the fuel rail

[This message has been edited by DEVIL'S LAKE (edited 09-09-2000).]

[This message has been edited by DEVIL'S LAKE (edited 09-09-2000).]
 

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For correct fuel pressure reading, it should be done with the vacuum line removed from the pressure regulator. You could have a leak inside the diaphram of the regulator or a leaking injector/injectors.
Perform an ohms test on the injectors first as this is really easy. If all fall within 13 - 16 ohms, then I'd look at the regulator. The only way to inspect this is to remove it.
Of course, first do the obvious and check all fittings from the fuel pump forward for leaks.


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67 Camaro LS6 454/TH400/12bolt 3.73
1989 TransAm 5.7L WS6 W/all the options
 

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Discussion Starter #17
All right... I have to check things out when I get home from work today, but let me first ask a few things here:

Do I need to have the vacuum line to the regulator disconnected when I check initial "turn key" pressure, as well as cranking/start-up pressure?

When the regulator has vacuum applied to it, it should hold it indefinitely, right? So, instead of removing it to look at it, could I simply use a vacuum pump on it and see if it holds that vacuum? If it does, it's good, if it doesn't it's bad, right?

Do I Ohms test the injectors while key is on or off?

Thanks for the all the help so far. - John '89 L98
 

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It could also be the plugs. I had a set of Bosch platnum plugs and they built up a small needle like deposit out of the center electrode. This closed up the gap to .015 to .020" and it would start harder and occasionally miss at idle (auto trans).
It was almost like the platnum tip came loose and slid out a little.

Also consider that if there is anything wrong with your battery or you have excessive starter draw where good voltage is not supplied to the ignition during cranking, the ignition will not create a good spark.

Check your plugs real close.
David

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Check my web page for First Gen Camaro suspension info:
David's Homepage
67 RS 327
69 Camaro Vintage Racer
65 Lola T-70 Can Am Vintage Racer
 

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The fuel pressure is checked while the engine is running, vacuum hose disconnected. The purpose of vacuum on the regulator is it holds the pressure down. As the engine rpms rise during acceleration, the vacuum drops, allowing more fuel to the injectors.

Yes, you can test the regulator with a vacuum pump. It should hold vacuum. All the regulator is, is a diaphram and a spring that applies pressure to the inlet port of the fuel rail. This makes the fuel pressure build to overcome the springs tension.

The ohms test is of the injector, not the wiring harness. While the engine is OFF and key is in the OFF position or not even in the cylinder, remove ONE connector. Using a digital ohm meter on it's low ohm setting, connect the red lead to either terminal of the injector and the black lead to the opposite terminal. Notate the cylinder number and the ohm reading on a piece of paper. Replace the injector connector and move on to the next until finished.

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67 Camaro LS6 454/TH400/12bolt 3.73
1989 TransAm 5.7L WS6 W/all the options
 

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dude i have and 89 camaro. think the fuel pump is all the way in the back of the car. when you get ready to start the car. first turn on the ignition switch and give the fuel pump time to pump the gas to your TPI. when you try to start the car with out doing that the engine is just turning over till the pump gets the gas to it.then try to start the car. Don't foget to check the filter under the car.

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Charles Taylor
89 Camaro RS
 
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