1991 firebird will not idle

90

Asked by Jul 16, 2016 at 09:01 PM

Question type: Maintenance & Repair

Ok so I bought this 1991 firebird that was
sitting for 3 years I brought it home got a
new fuel pump in it because it was bad then
I started my firebird it ran smooth for about
15 to 20 minutes and then it just died like
someone turned off the key. Now my firebird
won't idle at all it starts but just dies I
replaced the fuel injectors because there
were some that were bad I bought a new
throttle body there are no vacume leaks
there is no problem with a ground wire I
bought a new fuel regulator and it still won't
idle was wondering if it may have a problem
somehow still with the security because I
had bypass it but still bypassed it won't idle.

14 Answers

19,225

i have to ask. fuel pressure and filter OK???

1 out of 1 people think this is helpful.
Best Answer
90

I'm not sure it seems to be that the engine is just not getting the fuel

90

Yes the fuel pressure is and filter are ok

120

You can reset the ignition you just have to go on Google and find out but if the security light is on it will not let your car run for a long period of time maybe the computer notices something is wrong because of the bypass system why don't you try to take it off and reset the ignition

1 out of 1 people think this is helpful.
56,595

You have the VATS (Vehicle Anti Theft System) security system. Do you have a chip on the key as shown in the picture? If so, the most common problem is the ignition lock cylinder. It'll have to be replaced. The new lock cylinder will come with a template for cutting the new ignition key BUT you need the correct number VATS blank for the security system to recognize the key and allow the car to run. There were 15 possible VATS keys that were randomly used. Take the ignition key to your local GM dealer and they should be able to tell you which number key blank (1 thru 15) you have. If they no longer have the equipment to decode the key a good locksmith should be able to do it. Also, "unbypass" the security system. You'll have a lot less headaches. HTH. -Jim

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90

Now could this still be the reason why it won't let the car basically run because I can start it it just won't idle.

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56,595

Probably not. If it will only run for 10 minutes or not start at all then I'd suspect the security system. If it just won't idle I'd suspect the IAC (Idle Air Control) valve. HTH. -Jim

1 out of 1 people think this is helpful.
90

Oh my gosh I think you figured it out because I've even put a new throttle body on thinking that maybe the old may have been defective but this actually makes alot more sense to me because I have replaced about everything that has to do with the fuel system and that is what the problem is that the car just will not get enough gas. I'm hoping this fixes the issue because I've put quite a bit of money into this firebird but It isn't all that bad because I got the firebird for $500 and it is in real nice shape I was expecting this to be a scam but it wasn't so even if I were to put a grand into this it would still be in the margin of profit from this vehicle being what shape it is in has only one spot of rust other than that it is solid and nothing broken except that I cant get the engine to idle because when it did run by itself it was so smooth for not being started up in 3 years and the oil in it looked like it had been changed recently.

1 out of 1 people think this is helpful.
90

I would have marked you as the best answer but I accidently hit it on some other person comment

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90

I meant to say that the engine gets gas because I've pulled everything I could think of and the fuel is there it just won't idle so this makes so much sense to me and I hope this is the problem and if it is I want to thank you becaue I've been trying to fix my firebird for about 3 months now and I was losing hope in this engine and it is so strong and I really don't want to pull it and put a different one in so if this turns out to be the issue thank you so much you don't know how much this means to me because I'm only 20 and this is my first car ive actually bought with my own money and I was getting so angry with how it wasnt running I was expecting this to be a simple fixer upper because it looKS so nice and I've been dying to drive it.

1 out of 1 people think this is helpful.
90

Well that's not the problem my dad has been working on it when I can't or when I need help he already changed the air intake control valve

1 out of 1 people think this is helpful.
90

I just can't understand what is wrong with my engine it is so strong but It won't idle I'm on the verge of just pulling it out and putting a 350 in it I'm sick of it not working

1 out of 1 people think this is helpful.
120

Try looking online for the relearn procedure on your firebird pretty sure it doesn't have a chip in it does it? If you you have a passlock their is a relearn procedure

1 out of 1 people think this is helpful.
56,595

Any relearn procedure will not work in this case. Even if it were a Passlock security system. There is a base idle speed adjustment on the throttle body. If you look at where the throttle cable hooks up to the throttle body you should see a tiny screw. Your Dad may remember the days of adjusting the idle speed on a carburetor. Same principle. This screw is usually adjusted at the factory and should never be fooled with. However, in this case, since this is a replacement throttle body you may have to adjust it. With the IAC unplugged the base idle screw should be adjusted for the engine to idle at about 300 to 400 RPMs. I don't have the exact spec. for your Firebird but that's usually where GM wanted it. Another thing on the IAC is it may need to be adjusted. The IAC on my '93 Caprice needed to be adjusted if it was ever replaced. If you still have the old one from the original throttle body you can use it to determine the pintle length for proper adjustment. Is your check engine or service engine soon light on at all? HTH. -Jim

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