Resetting PCM

[SYNFULL]

Hi,
I am having idle creep issues and what worked for me before was resetting my pcm. I tried cleaning my IAC but that didn't work. What I would like to know is if they is a way to keep my radio settings
while resetting my pcm. It took me so long to program it, I would hate to lose it and have to redo. I think I saw a gadget somewhere that plugs into the lighter socket??

Thanks!

 

[cfiiman]

They do make those, I have one, but I think if you do that your pcm will use that power and not reset, someone will correct me if I am wrong. On another note i'm interested in hearing more about you idle creep issue b/c I have had a similar issue. Mine hangs (which I have read all the hang threads) but will come back down within a few seconds to 600 or so rpm's. Anyway it used to then bounce around from 600 or so to 1200 or so which was highly annoying, especially at a stop light, I think people think you are doing it on purpose. After reading several threads on fuel additives and knowing my car sat most of its life (bought it with 7K or so miles and it is a 94) I decided after reading one of Tom Fluid Guys posts to try a bottle of techron. Well low and behold my bouncing has stopped which is awesome, but my hang is still there. I've cleaned the iac as well and doesn't seem to do anything and I've synced the TB's so I was thinking of trying a PCM reset but I'm too much of a wuss lol, let me know how yours go.

 

[DrumrBoy]

Haven't thought of it before but can't you just take the PCM out of the car, wait a while, pop it back in and then retrain it with the key-on-but-not-start and depress the throttle slowly twice?

 

[SYNFULL]

I should have said idle hang, not creep.

That is what i was thinking with the battery- supplying power will not let it reset.

I had this idle hang issue before and I did get rid of it by resetting the pcm. I left it disconnected overnight.
It started about 3 weeks ago when i was stuck in traffic because of an accident. It took me an hour to go 1/4 mile. I was starting, stopping, starting, stopping. That's when it started again.
My idle stays around 1500 now. Sometimes it comes down if i blip the throttle, sometimes not.
I would give it a try.

They do make those, I have one, but I think if you do that your pcm will use that power and not reset, someone will correct me if I am wrong. On another note i'm interested in hearing more about you idle creep issue b/c I have had a similar issue. Mine hangs (which I have read all the hang threads) but will come back down within a few seconds to 600 or so rpm's. Anyway it used to then bounce around from 600 or so to 1200 or so which was highly annoying, especially at a stop light, I think people think you are doing it on purpose. After reading several threads on fuel additives and knowing my car sat most of its life (bought it with 7K or so miles and it is a 94) I decided after reading one of Tom Fluid Guys posts to try a bottle of techron. Well low and behold my bouncing has stopped which is awesome, but my hang is still there. I've cleaned the iac as well and doesn't seem to do anything and I've synced the TB's so I was thinking of trying a PCM reset but I'm too much of a wuss lol, let me know how yours go.

 

[SYNFULL]

Wouldn't I be cutting the power to everything by removing the pcm?

Haven't thought of it before but can't you just take the PCM out of the car, wait a while, pop it back in and then retrain it with the key-on-but-not-start and depress the throttle slowly twice?

 

[ViperTony]

I've reset the PCM three ways. The first is unplugging the 3 wire harness connectors to the PCM and waiting about 20 mins or so. The second is the Wizard's suggestion which is to disconnect the negative battery cable at the battery and touching the frame with it for an immediate discharge. The third is to disconnect the positive battery cable atop the PCM. I believe #1 may preserve the radio settings but don't quote me.

 

[DrumrBoy]

#1 is what I meant...though I wrote it poorly. You don't have to take the PCM physically out of the car, just disconnect it completely. Someone who knows the electrical system well can chime in, but I would think that whatever else is drawing from the battery when the car is off wouldn't be affected by disconnecting the PCM.

 

[SYNFULL]

I will give that a try. Last time I disconnected the battery also. I will try doing it without disconnecting the battery this time.

Thank you all for your input- I appreciate it.

 

[Jack B]

#1 is what I meant...though I wrote it poorly. You don't have to take the PCM physically out of the car, just disconnect it completely. Someone who knows the electrical system well can chime in, but I would think that whatever else is drawing from the battery when the car is off wouldn't be affected by disconnecting the PCM.

You are correct, just remove C1, C2 and C3. The worst spot is the battery terminal at the PCM, if the stud turns, you are going to buy a new power module.

 

[jerseydave]

There is a cigarette plug that has a 9v battery adapter on the other end of it. Plug a 9V in, plug in the cigarette lighter in and get to work, your presets will be saved. Works great when you have to take out a battery, not so sure about the pcm though.