TPI HELP

[91chevyz28]

I have a 91 Z28 and it has a rough idle problem and after the car warms up it will not start,eventhough I have spark. After the car cools down it starts fine. It only has a rough idle after it goes into close loop. I have replaced the following items:
oxygen sensor
distributor
spark plugs
spark plug wires
egr
TPS sensor
MAP sensor
cleaned throttle body
I also have a fuel pressure gauge and pressure is holding. I am starting to think it is the ECM since it gives me problems in the closed loop operation. Any ideas would be great.
Thanks Jason

[maroman88]

may be 2 unrelated problems... starter may be getting tooo hot, rough idle could be a ton of things... dirty idle air control motor (IAC), dirty throttle body, a bad plug or wire... start with looking over EVERYTHING really close

[91chevyz28]

I cleaned the IAC and throttle body and the spark plug wires are brand new.

[91chevyz28]

may be 2 unrelated problems... starter may be getting tooo hot, rough idle could be a ton of things... dirty idle air control motor (IAC), dirty throttle body, a bad plug or wire... start with looking over EVERYTHING really close

I forgot to say the motor cranks but will not start.

[chrisfrom nj]

i had the same prob with a 88 gta tpi i changed the ecm,spark plugs ,wires ,cap rotor,coil,iac,o2,all it was was a dirty fuel filter

[91chevyz28]

I replaced that also. Thanks

[BonzoHansen]

get a noid light see if the injectors are firing.

[91chevyz28]

I was thinking of doing the noid light. Thanks

[HeadlessNorseman]

do you have any codes? know what your fuel pressure is? If you havent done so, these are always things you should check before throwing parts at it. I had a similar problem that i traced down to my ECM being bad and it was the distributor having one stripped hold down screw. A

[91chevyz28]

No it has no codes and , I have a gauge on the fuel rail. There is no gas coming out of the vaccum hose attached to the adjustable regulator so the regulator is good.

[V]

when you jump the aldl terminals do you at least get it to flash code 12 to start with?

[91chevyz28]

Yes, that is the only code I get.

[91chevyz28]

Well, today I ohmed my injectors and 2 are bad. Number 3 injector was only 7.9 and number 4 was 8.0 when it should be 16.0. I ran the car to operating temp. and check the 2 bad injectors, the readings drop to 5.8 when they are hot. I was thinking of replacing them with Racetronix injectors. Any opinions?

[HeadlessNorseman]

replace all 8 not just the bad ones

[91chevyz28]

Yeah, I was not only going to replace the old ones. I am going to replace all 8 since there are 19 yrs old. Has anyone used Racetronix injectors?

[V]

i have racetronix ones, no complaints