[beepbeep]

Hi,

I own (imported) FWD 2005 Dodge Grand Caravan 3.8 to drive kids and stuff around. I have recently run into some issues that made me scratch my head. I tried chrysler minivan forums but it the range of advice offered there was rather limited so I now try here.

Basically, it is throwing CE light with P0132 code = upstream O2 too rich. Guided by advices on Chrysler forums I replaced O2 sensor. Twice. Still have the error.

Finally I took out my WBO2 logger and fitted it to Exhaust and sure enough, it is running rich. Lambda 0.92 at idle and ~0.95 at speed. So Lambda is telling the truth. It is running rich.

I then measured TPS and it is working fine voltage follows throttle angle. Third step was to measure MAP: I took it out on the bench and it is reacting to vacuum changes: 4.65V on no vacuum, goes down when I suck on it.

But there is a twist.. When I fit it on the car it reports 1.2V at vacuum idle. Manually raising idle to 2000RPM makes it briefly go to 2V but then quickly goes to 1.0V (= lower than idle vacuum value??). To me it seems that there is a "flatspot" in MAP response curve. Is this plausible? Unplugging MAP makes idle lambda regulation go to 1.0 (as it should) but it also makes car undriveable.

I hate throwing parts at problems so my first step is to order new MAP (quite cheap) and take it from there. If it doesn't help I guess next step would be to measure fuel pressure? FPR is apparently "built into" fuel filter and in really awkward space, so I would rather not do it if I do not need to.


Any input is appreciated.