RustX7

My car: 87 TII, racing beat turbo back, creeping death (I think that was his name) FCD. Regrounded ECU and nice grounds up the wazoo in the engine bay.

The story: Had a bucking problem while driving it hard in the upper gears, usually (maybe always) during WOT, at seemingly random RPM's (NOT the 3800 rpm hesitation.) After reading around a bit on here, it seemed that it was my TPS. Changed out my TPS (to a used, but good one,) adjusted it, and things were much better. However, there were still two spots of hesitation, this time reproduceably appearing at 4200 and 4400 RPM, and only at WOT and only in 5th gear.

I've continued to try to diagnose and correct this, most recently by trying in vain to adjust my idle mixture. After finding that turning the BAC screw and turning the variable resistor screw seem to do basically nothing and that therefore my mixture seems to be pretty much non-adjustable, I decided to try swapping the variable resistor for one that still had the factory setting. This seemed to make my idle very solid but also, my boost gauge now goes ALL the way up to as far as the needle can go as soon as I start the car, and stays there.

Did I fry something when I changed that variable resistor???

RustX7

Hrmm. I was just out there probing the variable resistor lines with the key in the on position and something weird happened a few times as I tugged on the harness. There was the sound of a relay or something clicking somewhere nearby, I think it may have been the fuel resistor relay. Also, the ever-present clicking from the BAC valve (due to the key being in the ON position) died down for a second and then came back.

I tugged around some more and I think the sensitive area is somewhere around the connection to my boost sensor. The external wiring there is pretty good, so that combined with my maxed out boost gauge leaves me guessing that there's a short internal to the boost sensor.

Has anyone ever heard of potential short circuits in our boost sensors?