1989 GXL with JDM TII engine. Running US harness. Just rebuilt motor, upgraded to hybrid turbo, basically BNR stage 4. Engine starts right up and idles, but as you can see from the attached log, the idle is high. I can't get it below the 1500-1600 mark. Can see timing is up around 31 leading and trailing. CAS has no effect on timing. Not sure what to check. I have looked for boost/vacuum leaks and can't find anything. Is there anything electrical I could be missing that would have this effect? I will dig deeper if this is limited to vacuum leak but looking for any other possibilities.

 

Hmm, didn't get the attachment. Let's try again.

 

Got some sensor readings, curious if this could cause a high idle. VTA1 reads from 3.19-4.99 and VTA2 reads from 4.05-4.74. Nowhere near spec, so I am just curious if this could cause the high idle. I will replace the TPS, but should I keep looking for anything else?

 

Your TPS is telling the ECU you are at wide open throttle, that will cause all kinds of problems.

You can also unplug your BAC (if it is still in the car) and see if the idle drops to normal

 

Unplugged the BAC and couldn't really tell any difference. Should I be able to? I did find a vacuum leak and fixed it. I can't find any others except for one where the backplate attaches to the compressor housing. Did some research and this seems to be somewhat normal. Not sure if it could be causing issues. I manipulated the bracket to get my idle TPS voltages within spec, but if I though the throttle it immediately goes lean according to my wideband and tries to stall out. Does this sound like TPS or more vacuum leaks? Attached is my latest log including VTA1 and VTA2. Oh, if I hit the throttle fast it will make it past the lean portion, but it is pretty tricky to move that way.