Ecm/pcm

well going to steal this alittle. have a friend that just did a auto to manual swap truck idles fine but will not run over 2000 rpm down the road. it is a later 01 and we swapped out the rear tranny harness and i have a late late maybe early 02 ecm from a manual would this fix the problem?? or i am even wondering if we are going to have to swap out the tranny harnesses back to the auto and cut the plug off?.
 
02 ecm wont work just plugging it in. different map sensor, and i think the cam sensor is different also because there is no crank sensor.

even if you swap the sensors, then whatever box he has wont plug in or work
 
odieub said:
well going to steal this alittle. have a friend that just did a auto to manual swap truck idles fine but will not run over 2000 rpm down the road. it is a later 01 and we swapped out the rear tranny harness and i have a late late maybe early 02 ecm from a manual would this fix the problem?? or i am even wondering if we are going to have to swap out the tranny harnesses back to the auto and cut the plug off?.
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Rollin Coal is right that there are sensor differences between the '01 and '02. I think the biggest difference is the oil pressure. For '01 (and prior) it's a real sensor with 3 wires (5v, gnd, sensor signal to ECM). Starting in '02 (and later) there is just an oil pressure switch (NOT sensor). Basically when oil pressure goes above a certain level (I think its around 5 or 7psi) it opens the contacts (normally closed switch) and the ECM uses a look-up table to determine what oil pressure probably is to send to the gauge on the dash cluster. I believe it uses coolant temp and engine speed.

I bet that if you were to resolve this issue, you would be able to go over 2krpm. I bet that the ECM thinks that there isn't any oil pressure and is limiting the engine speed to limit damage, but let you get home. Do the key dance and see what codes you come up with and go from there.
 
i have not swapped them as of yet. it was just an idea. what from just an auto to manual swap could limit the rpm of the motor tranny over temp light is on too?.
 
odieub said:
i have not swapped them as of yet. it was just an idea. what from just an auto to manual swap could limit the rpm of the motor tranny over temp light is on too?.
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i bet its protecting the trans that it thinks is overheating.

find out what resistance the computer wants to see at normal operating temp (too cold you wont get OD or lock up) and just wire a resistor up.
 
Sorry, guilty of skimming.

Swapping ECMs should take care of the 2krpm deal, but you're going to need to address the sensor issues. I know that oil pressure and manifold pressure are different. Do you happen to have the 2002 engine harness? That would keep you from splicing anything. Also the oil pressure switch uses completely different wires than the sensor did.

The trans temp light is in the PCM on the firewall. Maybe try plugging in the sensor that the truck came with? Just a thought there, I'm not for sure about that part.
 
thanks guys thats what he done swapped the PCM all good. runs like a top.
 
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