Hi,

I have a 1992 z28 5.7 TPI. Had the engine harness replaced because it was a wreck, so now I can interrogate the computer. Showed an EGR code. Fixed that.

Engine surges when warmed up. Worse under load. Removed TB and cleaned. Also ohm checked the injectors. All tested at 16.2-5 except 2, which were 6 and 8. I'm not experienced in this area. Are the low values promblematic.,...could they cause my symptoms, and last but not least, can anyone provide an opinion on whether Furl Injection Connection part number 198R53 are a quality injector?

Thanks in advance...Ken

 

i have a 92 rs that i put a s/d tpi 355 in. Computer is same as yours, my car as well was running crappy when warm and surged under power, turns out timming was the culprit and i had to adjust idle then reset the ecm i would check plugs, wires, and cap etc. start small work your way up

 

Those 2 injectors are shot. You're better off replacing the entire lot of them though, but yes, 2 bad injectors can cause that.

 

I had the same Symptoms, its your injectors. I i went through the whole replace and rebuild on everything on the TPI system. 2 bad injectors will make it struggle more to start, even though they will start the engine, make it run rough, and surge hunting for idle, and you will feel a instant surge while driving it on the road

 

Thanks guys. The car actually starts very easily. Runs smoothly until it fully warms up, then the surging begins and the idle is rough. You can feel the motor shuttering through the seat and floor. My brother thought I should check the timing as well. Anyhow, I've ordered the Bosch III rebuilds mostly because the price is right, and they've got a 3 year warranty on them. Also, they've had adaptors added so they're a direct fit. I'll post once they're in. I sure hope this does it!

Ken

 

Runs good til warmed up, has 2 bad injectors......
replace injectors,instal new plugs and replace the O2 sensor.

 

Thanks....gonna be a fun weekend.

Ken

 

i hope you come up with something i just had 1 injector replaced in my 5.0 tpi and it runs significantly better but now has the exact same symptoms as your 5.7 keep us posted if you find anything

 

I had the same problem. Changed the injectors and the O2 sensor. it ended up being the TPS. I think the best thing to do with these engines is to make up a list of common causes, and start replacing things until the problem is solved.

 

An update....FINALLY got it all back together. The car idle great now. Appears that the fuel injectors were the problem. Now I have another. The car gets hotter now, and my oil pressure gauge in the car bottoms out at stops. If I slip it out of gear, the idle comes up and the oil pressure comes up. I'm going to post this question in another thread, as I didn't have oil pressure issues prior to this repair.

Thanks for your help!

 

How? What did you find with the EGR code?

 

I replaced the EGR valve with a new one. (Amazon has the Delco for $58 new). I checked the selenoid and the vacuum lines and they weren't issues. The drivability issue continued after I replaced it, however, the SES light did not come on again at highway speed as it had. The surge issue was rectified by replacing the injectors.