I have an 89 iroc TPI...drove it saturday no problem...it sat sunday...and monday went to start it and it fired up and died. I can get it running by pumping the gas a little but really ruff and backfiring. I can usually pump the gas just enough to keep it running and when I am able to get the car up to about 3000 rpm's it runs like there is nothing wrong as soon as I let off the gas...pop boom bang dead. I have suspected the ESC and Knock Sensor but that wouldn't explain the normal operation after 3000 rpm's. I am pointing towards and EGR / egr selonoid problem. Just wanted to get some imput if anyone has experience the problem. I am going to be doing some testing tonight. I am not getting any trouble codes so I also fear ECM problems but the ECM does seem to follow through with its initial 12 code telling me the that it seems to be functioning properly.

thanks
stricnyne

 

i suspect a vacuum leak somehow

 

I am going to double check that...it came to mind. The only problem is that pretty much every line is brand new. Pretty much why I am suspecting the EGR or egr solenoid. One this I noticed when I popped the hood was the electronic connector that connects to the egr solenoid has fallen out. I plugged it back in and no change. I have a feeling if this had fallen out right when I started the car it may have it may have cause the solenoid or EGR to fail indefinitly. Luckily this can be checked with a few simple tests. The only problem is I can't test the EGR itself, it can't be vacuum tested.

 

if you can reach teh EGR itself get ur fingers underneath and try to push the diaphram up and down. if it moves you should be ok. but it shouldn't cause your idle to go bazurk.

how can you test the solenoid? there are two in the air divert valve and i don't know how to test them.

 

didn't think so either but everything in any book that I have read says that the EGR Solenoind itself can cause some weird idle issuses cause it comunicates directly with the ECM and basicly control the vacuum to the EGR. I will have to do a voltage test.

 

I ran all the tests and everything checks out good...except...I thought I would try and intentionally disconnect different sensors and try to instigate a trouble code but nothing. No codes...i am pretty sure most sensors with set a code when trying to start the car, but I am not completely sure if the car actually has to be running to set a code. I have a bad feeling it is the ECM this time...specially now I don't seem to be getting any spark.

I also found a really ugly problem with my positive battery cable. I replaced it now but probably to late. I noticed it had been fried in about 8 - 10 inches of length from the heat of my headers. I think it may have arched and crippled my ECM.