Zepher86Z28

Hi hopefully someone can shed some light on this cuz my mechanic after explaining this problem to him just told me how to set it.


I was having run problems after 10 min the car would up and die for no reason, so I swapped over to a spare ECU and hypertech chip stage 2 chip, and fired it up, it started up (as with the old ECU it wouldnt) but it was running incredibly rich and knocking real bad with the SES light, After flashing the code it was 21 TPS voltage too high. I checked it out with my volt meter, (Tuner Pro R/T wouldnt connect to ECU) and was getting 1.9 volts at idle, so yeah this would cause the running rough, so i went to adjust it and pushed all the way down to the end of my travel on the slots and it still reads 1.0volts. So i just figure the sensor is bad.

I had to move the car by then, so i fired it up and it ran better without the TPS than when it was connected.

Tried another used sensor, and bolted it in around the middle and again I got 1.9 volts, so i keep pressing down to try to bring it in to .54-.56 volts but again I bottom out a .9volts.

I check the Shop manual flow chart to see what wires on the ecu harness I have to probe, (do i do this connect to the ECU? or when its unplugged) I unplug the 32pin connector and probe the wires, and they check out good (light comes on when it suppose to come on)

anyone got any other ideas about this, I did a search on TPS and Code 21 and no one seem to have a similar problem like this. Just error 21 came up.

alexisgreene

Have you checked the numbers on the spare ECM to verify that it is the same as your old one? If it is, replace the aftermarket chip with the stock one from your original ECM. A good rule of thumb is to have things working in stock configuration before throwing aftermarket parts in the mix.

Zepher86Z28

Unfortunate I dont have the stock chip, the aftermarket one was in it since i bought the car, as for the ecu i dont know about matching numbers no sticker on the spare one I am using now but it was out of a 305ci 86 transam same year as my car.
I had it for 3 years now and the first 2 years it ran great, but when i brought it out of storage this year i only drove it 3 times. I just shelled out 500 to get it fixed, but it just crapped out the next day and its been like that ever since.