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Crank no start at times/rough loping idle

Old 05-04-2008, 05:43 PM
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Car: 1991 Z28
Engine: 350 TPI
Transmission: 700r4
Crank no start at times/rough loping idle

I am looking for some help/advice, my 89 GTA 5.7 TPI will crank not start at times and other times will develop a real rough lopey idle. When the vehicle will not start I have verified that there is no spark, the fuel pressure is good. I have replaced the ignition module, swapped in another module while the vehicle would not start, no change. The pickup coil is new as is the ignition coil, 12v present at the coil.
I found that the reluctor in the dist. has some cracks in it, can this cause a no start or the rough idle?
How about the EST module, will this prevent the car from starting?

Also, while driving the car at times it feels like something is holding it back, will not accelerate over 3k rpm, this feels like an igntion problem to me. No trouble codes stored either.
Old 05-13-2008, 11:27 PM
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Car: 90 RS
Engine: 350
Transmission: 700R4
Axle/Gears: 2.77
Re: Crank no start at times/rough loping idle

I am experiencing a similar problem with random no starts and a miss or stumble that comes and goes. I am curious to see if you find the problem. I am not sure if this is a ignition thing or a vacuum line thing. How do you change the reluctor?
Old 05-15-2008, 10:41 PM
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Car: 1991 Z28
Engine: 350 TPI
Transmission: 700r4
Re: Crank no start at times/rough loping idle

I just replaced my dizzy and have great spark but now the car will not start, this car is killing me! I need to check the injector pulse next, has any one seen a spark control/est module cause problems starting? I am starting to think my ECM went south, I checked for codes and it only has a 12. Any one have any suggestions?
Old 06-01-2008, 08:56 PM
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Car: 1991 Z28
Engine: 350 TPI
Transmission: 700r4
Re: Crank no start at times/rough loping idle

I figured out the problem! The resistance of my injectors were all over the place, I installed the Ford Racing #24 injectors and my car runs like new, it idles smooth and runs incredible. The spec for the injectors is 15.6 ohms to 16.8 according to GM. I had a few of the original injectors that were as low as 3 ohms.
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