ponttpi86

Ok I have a 1986 trans am TPI I replaced fuel pump and filter car sat for a few years.I replaced the fuel pressure reg.I checked the IAC and cleaned any carbon from it and the rod does extend when I turn on key.I checked TPS it is set to .5v and has smooth operation.I replaced fuel pump relay also.I ohmed all injectors and they are at approx 16 ohms I checked voltage to each injector they all have battery voltage with key in on position.Car will start and then shut off 2 seconds later.Also as it runs I press accelorator and it doesnt keep it running.If I hold down accelorator as I try to start car it wont even start.It does restart every time and I can hear fuel pump run every time for aprox 3 sec.Is there something im missing why is it not staying running? Anyone please.I don't think there is any vats on an 86 is there Any help would be appreciated thank you

Vader

You are correct. There is no VATS in the 1986 models.

What is the standing fuel pressure with the new pump?

ponttpi86

With key turned on and pump running for 2 to 3 seconds it reads approx 43 Lbs but won't stay running long enough to see what running pressure is I don't know if I mentioned but I did replace fuel pump relay also.Would the IAC have anything to do with keeping it running?

bop11

Do you have any oil in it? Fuel pump won't run after a few seconds if there is no oil pressure or the computer does not get a pulse from the ignition.

ponttpi86

Yes while cranking eng and as it starts momentarily there is a little above 30 psi on guage I bought a new IAC but don't think that has any thing to do with it not staying running correct??

Vader

The 43 PSI is perfect. Since the fuel pump will run its prime cycle and develops sufficient pressure to start, it may be that only the cold start injector is operating and the service injectors are not firing at all.

bop11 is correct that the ECM must receive ignition reference pulses to fire the service injectors, and is also correct that the oil pressure switch acts as a backup power path for the fuel pump. However, since the ECM will operate a pump prime cycle the oil pressure switch should not be a factor in your case since the ECM and relay are obviously able to operate the fuel pump.

I'd suggest verifying the INJ1 ans INJ2 fuses are intact and supplying the necessary 12V to the two banks of injectors. Once that is verified, check the operation of the service injectors with either an analog meter or test light. If the service injectors are not firing, it may be necessary to inspect the wiring between the injector harness and ECM, including the connectors between them, specifically C221.

ponttpi86

Thanks for reply I have checked for voltage at injectors each one has battery voltage but not sure of the pulse when cranking.I did ohm the CTS and it has 0.034 ohms on a 200 setting .at approx 60 degrees ambient temp witch is very low I believe.I'll get a noid light and check each inn circuit for pulse.
Thanks