What information does the computer use to determine the amount of fuel needed at start-up? I still have a terrible starting problem, and I am now completely lost. It is fuel related, because I can spray fuel in the plenum, and the car cranks right up. I have replaced the computer, Prom, MAT, CTS, and fuel pump relay. I have no codes, and my OTC scan tool says everything is in range. I have done all the normal fuel system checks, (pressure drop, set pressure, etc.) and have tried starting with the MAF disconnected. Nothing has made any real improvement. I am not positive that this is an ECM related problem, but I cannot find a mechanical problem with the fuel system. Thanks in advance for any help.

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'89 GTA, Ported Plenum, BBK throttle body, 24lb Motorsport injectors, Jet stage 2 chip, AFPR, no cats and a Flowmaster.
'95 GMC soon to be 383 daily driver w/Howell multi-point injection conversion

 

I'm gonna take a WAG and say it's ignition related. With this "terrible starting problem", does it crank for a while before running on its own, or does it not want to crank over at all? If your answer is choice A and your fuel pressure is OK (along with everything else you've checked), then I'd look at the ignition system (plugs, wires, coil, module, cap/rotor). If answer B, then it's either the starter or the solenoid.

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Greg Westphal
'87 IROC 305TPI/A4

 

It does crank over fine, it just doesn't fire off. If I prime the plenum with a little fuel, it fires up instantly. That is why I am thinking I have a lack of fuel flow from the injectors. If it was spark related, it wouldn't fire when primed either, right? Thanks for the input, I am going to get this fixed one of these days

 

Maybe the injectors are clogged, or the fuel filter needs to be changed. What are you actually spraying into the intake? If it's just gas, then I'd lean more towards a fuel delivery problem like you're thinking. If it's a starting fluid, then it -could- still be an ignition problem since they are easier to ignite than gas.

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Greg Westphal
'87 IROC 305TPI/A4

 

I am spraying gas into the intake. I have replaced the fuel filter, and I hope the injectors aren't clogged, they are new . The car does run fine once it starts, it just takes a few times trying to get it to start.

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'89 GTA, Ported Plenum, BBK throttle body, 24lb Motorsport injectors, Jet stage 2 chip, AFPR, no cats and a Flowmaster.
'95 GMC soon to be 383 daily driver w/Howell multi-point injection conversion