72IH

If the engine from the 99 got its engine speed/tach signal from the crank position sensor and toothed ring inside the engine, then where does the 2001/2 engine derive its engine speed from? It doesn't have a crank position sensor or ring so what sends the signal.

Reading somewhere else here it says the cam position sensor only is diagnositic and sends the TDC signal to the ecm, not the engine speed. Is this true? If it is then why would this not be working with the new ECM and PCM?

Kennys

Could be a difference in the wiring harness.

72IH

Right. There most likely is, but what is it. If its just a lack of the pin out off the ecm for the crank sensor then easy fix. Just undo the wires off the ecm.

But is it more complicated? That seems to be the only difference I have seen on a wiring diagram. Those pins are just not used. At least on what little info I can find on the difference on the harness of the ecm. Only thing I can really find is on the 99 to 00 ecm. Cant find anything for sure on the 00 and up ecm pins and where they go.

There is a 5v line into the sensor a return and a ground I assume. (three pins on the sensor i think) If all we have to do is leave it unplugged then no go. It won't start without the sensor plugged in. It will run about 30 seconds then die.
With the sensor plugged in it will run and drive but doesn't get full throttle and lacks power.

I guess short of swapping cranks the only other option is to add a tone ring for the sensor on the front somehow and move the sensor up there.

I may also try to change the alternator. The one on the 99 has a different part number than the one on the 2001. Could that be where the tach is getting it's signal from on the later engine? Is that why when there is not tach signal on later models (2000 to 2001) the alternator is not charging?

If it does get its tach/engine speed signal off the alternator then I think a harness swap may work, or just a simple alt swap.

97Dodge

So what we found out was that when putting the 2001 motor in the 1999 truck we had to use the harness and the ECM off of the 2001 . Pcm for the 99 works fine with the 2001 ECM. anyhow thanks for everyones input if you have any ????? feel free to ask