1LESSZ28

97 camaro a4 lt1 car wont start after replacing fuel pump (sat for a while before pump replacement) here is a list of stuff I have checked with results:

1. Fuel tank emptied and cleaned new pump assembly/sending unit intstalled new fuel added (~8 gallons)

2. Fuel pump working (hear it starting up and shutting down)

3. Fuel pressure over 40 psi after key is on and holds around 40 psi

4. Getting spark on spark plugs. Checked spark energy with a commercial tester on the coil and a couple plugs getting nice blue spark at .085 inches on a commercial tester.

5. Checked Coil primary and secondary winding resistances and they check within specification. Power and signals to the coil and to ignition module are also as specified in a haynes manual i have.

6. Also backtested signal on the distributor connector and it checks out.

7. Checked several injectors on each side of the engine with a NOID light and the light is flashing nice and bright as the NOID instructions say it should if it is functioning properly.

8. Injector resistance measures within spec.

9. Car has a new 630 cca battery which I keep charged up.

10. Muffler was cut off due to provide access to tank and is not on the car (probably a non-issue)

11. New air filter, fuel pump, fuel filter, all fuses are good, grounds check out, pcm seems to be working and has fresh oil and filter.


Any ideas? please somebody anybody lol. Car seems like it wants to start (cranks fine but does not quite catch). Can smell fuel out of the exhaust. Could it be IAC? rpm's bounce around slightly when trying to start. fuel pressure is good.

mrmint69

How long did it sit for and why did you replace the fuel pump? Was the pump for sure the problem when you replaced it?

1LESSZ28

old fuel pump failed for sure (no buzz) new one is good. sat for several months.

Dave89IROC

flooded?

you try holding the gas pedal to the floor while cranking?

1LESSZ28

absolutely not. who does that on an efi car anyway?

Guys, after much testing, headscratching, and swearing I think I may have tracked down the problem. As I suspected it looks to be the IAC after all. I had a friend hold open the throttle blade and I cranked and it ran and as long as he held it open it stayed running. Does this sound like the IAC to ya'll or something else?

Dave89IROC

umm, holding it to the floor while cranking puts it in "clear flood mode", which cuts off the injectors, so, anyone who reads the owners manual knows what it is..................................


and yes, it could be the iac, disconnect a vacuum line and try to start it

1LESSZ28

the iac voltage checks out and I was thinking the passage could be clogged. any advice for checking this out?