'95 LT1. I need to load a new tune to finish a a4-m6 swap. This is in tunercats. I used to be able to load tunes no problem, but now it turns on the fan for a few seconds, then says no response from PCM. Then if I turn the ignition key on again, the fuel pump won't prime like it's supposed to. The car won't start, but if I pull the PCM fuse and then plug it back in, the car will run fine again, but I can't get the PCM to take a tune.

Any help?

 

Have you tried loading a different bin file?

 

Yes, it won't load any bin file that I try.

 

Maybe the pronlem in tunes themselves?

 

I'll try loading a tune that I have not done anything with and report back.

 

Same thing happens. It doesn't even get to the point of loading the program. It gets about 75% through the part of establishing communications. It either says "Invalid response from PCM" or "No response from pcm".

 

If your able to try it on someone else car I would try that and see what happends. If that doesnt work then i would delete the program and reload it again.

 

I can't do that because I don't know anyone else around here with an f-bod. I'm at my whit's end and think maybe it could be a PCM problem, or another very likely candidate is my laptop and cable.

 

If your battery voltage is too low, it will do that also. Put a meter on the batt and see what it's reading. As a quick test, hook up a set of jumper cables to a good car with a strong battery and see if you can do a read on it. Definitly make sure you can do a read first before programming, cause if it dumps on the program, your done.

Ken R.

 

Meter reads 12.5 volts. Put the battery charger on the battery while trying to do a read, same thing. I even pulled the relay for the fan, no difference. I have absolutely no idea why it's doing this. I may be able to try a different laptop tomm.

 

Do you have any problems reading from the PCM? You might check your cable too, something might be wrong with the converter part. I've had that happen before in the past. I doubt the problem is with the PCM, if it was, you wouldn't be able to get the car to run. Are you doing this in Windows? You might try going to DOS through a boot disk and try reading/programming that way. I've never had any good luck using the WIN version of the flash programmer, it's too buggy due to WIN. DOS is the best way to go.

 

I used datamaster to do a log. So apparently It can read just fine. If anyone wants to look at the file for me, just PM me and I'll email the file to you. I tried using PCMread, still wouldn't work. I am using the Belkin F5u103 serial to USB adapter, and I don't think USB works in DOS. I'll try using hyperterminal to test the cable, but since it worked in Datamaster I think it must be ok.

 

Are your grounds good? Specifically the one on the passenger fender near the battery? That will cause havoc also. This all sounds like somekind of connection issue. I agree with the above post about it probably not being anything related to the pcm. Have you always used that USB setup without issue along with the laptop? If so, then theres something going on with the car itself from a connection perspective probably. Hate those bugs.

Ken R.

 

odds are it's your computer setup. I had misc problems with USB serial adapters and went to a PCMCIA serial adapter and all problems went away.

USB Serial adapters are not really 100% and most documentation even says so. Best bet would be hauling any computer with a real serial port on it and try to load a file... if that computer doesnt work try another.

 

Agreed. USB really isn't something that should be used for this type of data transfer. I love the ease of use and compatibility of USB for stuff like flash drives, printers, and computer accessories, but when it comes to older equipment like OBD1 ECUs and PCMs, a real RS232 serial port is a must.