1984 Dodge Rampage Turbo
UGH, MAP sensors. Guys over at TM forums actually bench test the sensors with air compressor. Put a regulator on, and carefully test the full range of the MAP.
So here's what I've tried. I eliminated all manifold vacuum except MAP/BAR, brake booster, FPR, and PCV. (It's pretty hard to disconnect the PCV, but I also swapped out the grommet and even tried zip-tying every joint.) The wastegate solenoid was also still connected. Behavior was about the same, and the buck/surge problem was still present.
I bought a $15 TPS on eBay. It was 0.75v at closed throttle, 3.96v at WOT. However, the computer immediately (and consistently) gave code 24, "Sensor output less than 0.16V or greater than 4.7V". Reinstalling any of the used sensors cleared the code. I then bought a $36 TPS from CarQuest. It did the same thing.
I soldered a new ground from the TPS harness to the throttle body and also to the battery negative. No change.
I replaced the MAP/BAR with a set from another 16v Spirit, and it refused to run. It would sputter and cough, no codes. I put the original pair of sensors back, and it worked "normally".
I'm out of things to try. I'm not doing anything exotic. I'm just trying to get it running STOCK!