As I've posted in some other threads, I recently purchased a 1995 F-350 with 260K on it. Have been troubleshooting some different issues with the help of forum members but wanted to start a new thread on this because it may account for multiple of the other things. The guy I bought the truck from had the tranny rebuilt about 15K ago, at which time a shift kit was added so firm shifts are expected. But this sucker shifts HARD. Like backbreaking hard. I called a local tranny shop and they offered to do a basic diagnostic (scan it for codes, test drive, etc.) for no charge. So I took it by there this afternoon.

There were no transmission codes but there was one for the MAP sensor and one that he said is what you typically see when a truck has been chipped. But this has not been to my knowledge, nor could we see any evidence of that. So we took it for a spin. When he put it in reverse and heard it pop into gear he said that doesn't sound right. And agreed the shifts were way too hard going down the road. He mentioned that it sounded like the APC (or EPC?) solenoid was not functioning right. Looking at his scan tool, it showed 12volts to the solenoid, which is supposed to be between 0 and 5v. Between that and the odd computer codes, he is thinking the PCM is bad. I left the truck overnight as he said tomorrow morning he can put it on a different kind of computer based tool / breakout box and verify whether it is the PCM or not.

The other issue I am troubleshooting is a rough idle when the engine is cold (below normal operating temps). I have another thread on that. I was thinking my next step woudl be to take it and get a buzz test and CCT done. But I'm wondering if a bad PCM could contribute to that problem too? If it's bad, it would seem starting there would make sense.

Questions:

1. Does this sound reasonable to those of you more knowledgeable on transmission and/or the PSD in general? The PCM being bad I mean?

2. If so, and the PCM is bad, it sounds like one can be had for about $300 aftermarket. That's what the shop quoted me and I also googled it and found a site that exchanges them for about that amount. But I also found them on car-part.com (junkyard search) for anywhere from $75 up. Most of the time I think the boneyards are great, but not so sure about electronics like this. Has anybody gotten one from a junkyard? Will it have been tested, etc.? I know most offer a short (60 day or so) warranty.

3. I read on another thread (not sure if it was this forum or another) that pretty much any PCM from a 95-97 truck can be used and that it might be best to go with a 97 of a certain model. Does that sound right?

4. Should I go ahead and let the tranny shop change it out or do it myself? This seems like a pretty simple repair.

5. Any other thoughts or recommendations?

 

I'm running a used TDE1in my 97 for three ,almost 4 years now ..I think the only issues are manual only PCM & cali model with splits .. Madvan (Bill will know )

 

I can't believe there is a problem with the PCM. I suppose its possible. But I think smoke is being blown in your direction. Is this the tranny shop that did the rebuild?

 

Did your truck originally have the TDE1 or did you use a different code?

 

Not that I'm aware of. But I just bought the truck. PO did the rebuild.

 

It had a TDE0 before. TDE1 is the last ford upgrade .

 

Well this sucks. Ford wants $550 for a PCM. Tranny shops source for reman would have to have the old one sent in and get it back to us in 2-3 weeks! For $300 or so.

Found an online source (autocomputerexchange.com) that has one for $295.

No local junkyards have them ... found one in KY for $125 but they don't offer ANY warranty (not even 30 day) on computers.

But I'm not even sure this is what is wrong.

Can a PCM be bench tested? Even if I have to go to the dealer it might be worth it.

 

Ford dealer can re flash it for you. If somebody in the past downloaded different software to it then re flashing it will put it back to factory stock. A lot of problems on here have been resolved by having the PCM re flashed. It's a crap shoot because you don't know if it has been modified or not. Your mechanic indicated he thought it had been chipped but there are other tuners out there that flashes the memory instead of a chip.

 

Look here .. sort by distance

 

That's where I found the one in KY.

 

Great point. I just called the local dealer and the will do a diagnostic for $89.95. So I think I'll do that and see what they have to say. Even if they come up with the same diagnosis ... at least I'll have a 2nd opinion.

 

I had completely forgotten about a tuner hosing the PCM up. If you do head to the dealer ask if they can re-flash it as stated above.

 

Just made an appointment to get it re-flashed. $90. Can't get me in until Monday but that sounds like a great next step. And if the PCM truly is damaged, they'll discover that in that process I'd think.

 

This is a lesson learned over time ...

There are lots of threads on how to purchase a used PSD and what to look for. The one thing I always demand on any used vehicle is that it be stone cold when I arrive. I tell the owner I'm going to feel the exhaust manifold and if it's not cold I'm gone. They have giving all kinds of excuses over the years but I just walk away, regardless on their great deal .. they are hiding something.

 

Great point ... and I should know better. Well I'm on the path now so I guess we'll see where it takes me.