Can incorrect IAC or TPS adjustmens cause problems like extended cranking when you try to start the car?

Thats just about the only thing I've not looked into right now, since my voltmeter died last week when I was going to investigate the problem a bit deeper....

(Might be the cold weather also, I don't drive the Camaro during winter, just making it ready for the coming spring....)

Any suggestions about what else to check?

The MAF is new, so I think we can rule that one out, and I've checked fuel pressure and ignition timing, pickup coil and ignition module is also new...

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ZaphodB a.k.a Carl Andersson - zaphodb@faxancruisers.org
'89 Camaro IROC-Z 5.7L TPI - Mods under construction :-)
Ed Wright Fastchip Stage II/160 stat, Edelbrock TES Headers,
SLP Airfoil, K&N Filters, Accel 8mm wires, Relocated MAT, AFPR @ 47 PSI

 

I have an 89 IROC 5.7L TPI also, and I also have an extended start problem. It occurs if the car sits for anytime between 10 minutes to 8 hours. This is due to faulty "Multech" fuel injectors, and from what I have been told is that they are a bad design which are prone to leakage.

 

I would check your fuel pump relay. When you turn the key to the "on" position, do you hear the pump run for about 2 seconds? If not, your fuel pump wont start running until you have oil pressure.

You may also want to check your IAC bore for deposits, but usually hard/extended starting issues are fuel or spark related. If you suspect IAC, disconnect your brake booster line at the booster, and try to start the engine. This will create a big vacuum leak which would rule out a lean A/F ratio. How long do you have to crank it? Is it worse after sitting for an extended lenght of time?

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-Jason M. 1991 Camaro Z28
"...with his loose skin and old... *****, gross!"

 

It usually fires after 4-6 revolutions.... But the fuel pressure doesn't drop after I shut it off, and if I turn the key to on without starting, I hear the fuel pump run, so the FP relay should be okay...

 

I had the same problem with my 87 350TPI, chased the problem for years, even GM couldn't figure it out under warranty. I adjusted the TPS to the max voltage at closed throttle and it now starts at the touch of the key.

Gary

 

Gary,
When you say you adjusted the TPS to max voltage at the closed position. What specific value did you use for this setting?

 

My car is stored away for the winter so I can't check it for sure but I set the voltage at either .060 or .062 volts. Made a world of differenc when starting the engine hot.

Gary