PCM Open / Closed circuit

[jldiaz]

Is there a failsafe way to know when my PCM (2001) is working in open or closed circuit with the O2 sensors?

[old_man]

If your computer is running open loop after warm up, due to a bad sensor, it should be throwing a check engine light.

[jldiaz]

Thanks, old_man.
The trouble is that I think my PCM may be bad. I've done lots of tests and never gotten a check engine light except when turning the key to "run". There's awful misfiring in the 2000-2500RPM range when manifold vacuum rises while I let go of the gas to even out after accelerating. Probably when switching from open (accelerating) to closed (cruise).
Since I haven't been able to index my camshaft sensor properly (No scanner. I followed the FSM as far as I could go and then advanced it to the point where the engine starts ok and doesn't stall.), this could be the cause.
I opened another thread about "camshaft indexing", but there are no ideas yet.
On the other hand my O2 1/1 sensor seems to be shot too, since it reads over 1.5V at the PCM connector on a warm idling engine.
Any ideas, anybody?

[Sparkman]

If your O2 sensor is indeed bad I would start with that. I thought that O2 sensors were supposed to output a voltage between 0 and 1 volts. If your PCM is seeing 1.5V I would think it would light the MIL. Maybe you have the wrong pin on the connector.

[jldiaz]

Right. The FSM says 0-1V. I´ve double-checked the pins and wires, so I´ll be changing the sensor. Hopefully tomorrow, if I can find the spare.
Will keep you guys posted.

[Sparkman]

I would double check your meter. Take a new AA battery and test it, should be around 1.5V. I can't believe you aren't getting a MIL with that voltage. Maybe the PCM is bad.

[jldiaz]

Update: I won't have my new O2 sensor until wednesday or thursday (09/02) . The dealers had to order it last friday and the Chrysler assembly plant (100 miles away) won't send it any sooner.

[jldiaz]

Update: The O2 1/1 didn't come in on thursday.
Well, it did; but they got the wrong one ('99). They ordered the (supposedly) right one ('01, with the four wires), and it should be here on tuesday......