Looking to save a little time if someone can help. A lot of those on this board seem to be pretty sharp so I thought I'd ask.

have a 1988 IROC-Z, 5.7 L, TPI.
Car starts great on first spin when cold.
Once warmed up and setting for a few minutes, it's hard to start and requires flooring the throttle to WOT so the computer goes into flood mode and shuts off the fuel.

Then it starts with an overly rich exhaust and with the smell of too much fuel.

I suspect a leaking injector but am unsure it it's one of the main eight, or if it's the cold start injector.

Is there any easy way to tell without tearing the Air Plenum off and lifting the injectors so you can see the fuel spray out?

Any advice is appreciated.

 

could be, also something to think about is this...could be an ignition module on its way out, a lot of times when they are ready to go they don't work as well when they are heat soaked. One way to see if its the injectors is get a fuel pressure gauge...hook it up to the schraeder valve on your fuel rail...see how long it takes for the rails to loose pressure after turning the car off, my injectors are shot, takes about 5-10 seconds too lose all pressure after turning the car off

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*89 Trans Am GTA
*Moderator at www.transamgta.com

To hell with the GM vs Ford war. We must unite, as brothers to fight the plague that is overtaking the world...RICE

Tony

 

Hook up a fuel pressure gauge. The system should hold pressure for several minutes after shutdown, a leaking injector will run to zero quickly.

 

I'll get the gauge and go from there. Thanks, never thought of ignition module causing it, but since the exhaust is so rich with fuel and has some white smoke, I figured it was the injectors.

 

The fuel pressure test may not do you any good unless the fuel pressure drops to zero VERY quickly. I have brand new o-rings and screens on my injectors but my fuel pressure will drop to 0 within a couple hours.

As far as it being the cold start injector, not possible. Once the engine warms up and goes into closed loop operation the ECM stops the signal to the cold start injector switch (located on the front of the intake next to the coolant temp sensor) and the cold start injector shuts off. It's only used in open loop to provide the engine with a little extra fuel which would explain why the car runs fine when cold. The extra bit of fuel that the cold start injector provides is compensating for the leaky injector and then in closed loop you have the problem because the cold start injector is no longer operational.

It could be the ignition module but that's not likely... chances are if it were the module the car wouldn't start at all until the module cooled down.

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1986 Trans AM
355 TPI
4 Wheel Disc Brakes
9 bolt Borg Warner Rear (2.77's....oh joy) :P
6" rods, approx. 9.7:1 Compression, Stock TPI (soon to be ported), 24#/hr LTI injectors (cleaned and flowmatched by Cruizin Performance), Hedman Shorty Headers, 3" exhaust with 80 series flowmaster, SBC 993 heads completely redone and modified for 1.6 RR, 1.52 RR (for now), Comp Cams XE262-14 TPI Cam, Holley AFPR, TPIS airfoil, MSD wires, MSD 6-AL Ignition, Hypertech 53,000 volt coil.

Track times to come.

[This message has been edited by 86TpiTransAm (edited November 25, 2001).]