'86 IROC 305 TPI. Following Vader's instructions but when I test the voltage I am getting 4.5 volts with the throttle closed and as I open it the voltage drops to 1.25 at WOT?? That's backwards isn't it?


I am using the middle blue wire and bottom gray wire for testing. What am I doing wrong?

 

 

OK, it was a little low on both ends. Got it dialed in within specs and now it won't run. I can't even keep it running. Every time I try to give it gas, there is nothing, no response and it eventually stalls. Before, it didn't want to idle cold but once it warmed up a bit it would idle on it's own. Way worse now. Could the TPS be bad?

 

Did you do the IAC adjustment first?

THEN TPS??

https://www.thirdgen.org/newdesign/tech/tpimod2.shtml

 

Yes I did. At least as best I could. Really couldn't get it to idle below 1000 RPM's. I also tested the IAC according to the shop manual yesterday and it checked out.

 

If you couldn't get it to idle below 1000rpms while doing this procedure, you got other issues!. Start looking at/for vacuum leaks, intake leaks, loose bolts, and the like

 

Hard to believe I have a vacuum leak since I just put it all together and used new vacuum lines and torqued everything to spec using brand new gaskets. It was a very rough idle and it was hunting a little. No I can't even get the damn thing to stay running.?? Very frustrating. I was planning on checking the fuel pressure today. I was suspecting fuel pressure or bad injectors...


I tried putting the TPS back to where it was and it's the same..Now what?

 

Why is it that the later TPI cars not have an adjustable TPS? The hole in the top TPS mount is round not bean shaped like the earlier ones.

 

The later cars take the value of the TPS at key-on as the low value for the sensor, so self-adjusting in a way.