I currently have all scaning software (Craig Motes). My car does not always start, and if it does it dies at random. Sometimes it runs a very smooth and sometimes it surges. It does not run long enough to drive it any where. Sometimes the stall saver will save the stall and sometimes it just dies. the fuel pressure stays above 35 psi at all times, 40 psi while cranking. The fuel filter is new and voltage is always being supplied to the fuel pump. Could a mass airflow sensor cause this. I was told in TPI forum that a MAF would not cause a car to not start. The TPS is new and functioning correctly. Could the IAC be causing this. The Oxygen sensor is new. What can i look for in the software or otherwise to trouble shoot the problem. I have never seen the software hooked up to a normal running car so i have no basis for comparison. Please help me, I am moving soon and would not like to have to tow my car to the new house (30 mi away). Any suggestions are appreciated.
thanks
jake

 

Kinda sounds like an IAC going bad or the IAC port is clogged. Try cleaning the IAC port w/throttle plate cleaner first then go for a new IAC.

 

I replaced the IAC motor and cleand all the pasages. the motor started and ran fine for 10 minutes. Then it stalled. I checked the fuel pressure just after it stalled and it was 0. I tried to restart the car and the starter just clicked (never happened before). I will get the alternator tested tomorow, but it is less than 1 year old.

I know this is not really PROM related but i figured i would follow up on your last post.

If any one has any suggestions i appreciate them. Is there any thing i can look for in Craig Motes data software?

 

Sounds like the Fuel pump Relay may be going bad. Try swapping it out with the maf Burnoff relay if they are the same plug type (some are oval, some are square). I don't know if craigs software will display fuel pump voltage but if it will, check to see what you got as it dies. You should be able to find hundreds of these at a junk yard for about a buck or less a piece. They were used in almost all GM Fuel Injected cars for maf, Maf burnoff, and fuel pumps. Hope this helps.
Don

 

Fuel pump relay is new and Craigs software does show voltage to the pump at all times. I have found a mechanic that suggested reading the amps in the fuel pump relay it should be 3-4 amps if less my pump is most likely bad, i have not had time to do this yet though.
thanks
jake

 

Think Fuel or Fire. How's your spark plugs these days?

I'd like to say that I've had this problem before. Except for the fact that mine would just die at idle just like if you were to turn the key off in the middle of driving. Now mine turned out being the IAC valve adjustment and eventually leading to replacement. Here's what I would go after in your case...

The F*cking weak HEI modules in these cars. After so long they crap out totally. Inspect your cap/rotor while you have them off. These HEI modules are rather inexpensive. However you stated that the fuel pressure dropped to 0 when it died on you. Not sure if that is a good thing. Could be a faulty fuel pressure regulator or a dying fuel pump. How about just supplying 12V to the fuel pump and listening for operation??

Just thoughts,

Brian P
89 IROC-Z 355