mstanhope

we have vac at the map sensor, and have even swapped in a new map sensor to be sure... still no change. did not check the fuel injector yet. the coolant temp sensor had 3 wires, the single wire unit should only be the sender for the temp gauge on the dashboard (or light if you have the base dash)

Hi All, first time here so excuse me if I ask dumb questions! At work, a customer of mine has an 87 AMC/Jeep Comanche 2.5L with the Renix TBI EFI system. It runs pure rich ALL the time. We have used our scanner and gotten into the ECM and the only sensor that was out of range was the O2 sensor, so we replaced that as well as did a full blown tuneup including plugs, wires, cap, and rotor. None of this helped. My co-worked thought that maybe the ECM was misinterpeting signals from sensors, but showing everything OK on the scanner, so we got a replacement ECM from the junkyard from another 87 Comanche 2.5L. No change. So looking deeper, still not finding anything, we replaced the coolant temp sensor since these have a tendancy to make the engine run rich if they fail (this one was reading a good temp and voltage, but we did replace it anyway). No dice... so we still have a 2.5L AMC motor that is running full rich. We are running out of options. We have checked vac lines and intake manifold for leaks to no avail... any help would be greatly appreciated by us and the nice old guy who owns this truck...