PCM Flash

Ok tuning experts! I'm needing my PCM flashed and have called Ford and several other mechanics in the area and they all need my truck in order to do this. However the tuning guys just need the PCM. My truck is in the shop now and the guy calls and says he can't reflash it because there is a bad module. Can someone explain this to me in terms I can understand? Just me thinking here but if the PCM was flashed without it in the trucks a module wouldn't be hindering it. Then maybe everything would be ok?

does the truck RUN with that PCM??

Yes it cranks up and goes in reverse but when you put it in any forward gear it won't go forward. Like something is locked up. What I did was stupid. I put an edge Evo Programmer on my truck from a manual 7.3. Mine is an auto 7.3. It's stuck in another tune and won't go back to stock. I spoke with edge and they are talking with the mechanic now to see what needs to be done. Edge said they would need to update the tuner in order to get my PCM to stock.

They talked the mechanic through the process and got it to stock setting but my PCM has the other truck PCM info on my computer. The mechanic wanted me to buy a PCM. I called Edge and they're overnighting a Programmer with my info on it. I just plug it in and let it program. Dumbass mistake on my part but lesson learned. I'm going to order a PHP hydra chip next week.

Ok smart guys I've got a little issue with my truck. We hooked the Programmer up and followed the directions and everything worked out. I couldn't tell any difference in how ran before my stupid mistake. After about a week my glo plug relay went out so I went to advance auto and got one. It didn't work even once. So I've been jumping it out every morning. Then I noticed it's not running quite right. Cranks up fine,isles normal but loses power after takeoff. I've serviced it and cleaned the S&B filter. The past few days it acts as if the brakes are are holding it back. At 60 mph it's tacking @ 2000rpm. Normally at 65 it's at 1750rpm. I had already put 3 new calipers on with new pads and today I put a new caliper on right rear. I didn't change the fuel filter after the pump for about 3 oil changes. I'm going to pick one up in the morning in case it's a fuel issue. Now, maybe this is coincidence but it doesn't do this all the time. Today out runnng errands it ran like this. But then later I got in and ran just fine. Went to eat and dropped off the core at advance. I was on my way back to my camper and when I turned the defrost on rpm went up and acted like no power.

Sounds like the tc is unlocking.

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I had thought about that to. The transmission temp will get up @ 160 but when normal @ 110,at least this time of year. My tranny is a HD built. And when it changes it hits hard. Turbo sometimes won't boost past 10 but normally 20 or 21lbs. It's stock and I've noticed some oil residue at the intercooler boots.

Ok what about "Transmission Speed Sensor" or ABS sensor . My cruise isn't working either. The abs light isn't on according to the description of the parts both of these sensors can change shift points. Looks like I'll have to get a mechanic on this one!

You may have a light out.

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Tail light?

Usually. Or 3rd brake.
Could also be a intermittent connection issue.

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Tail lights are fine. Transmission sometimes won't go in OD sometimes and acts like it's not getting enough fuel. Stop at store come out fire it up runs like a raped ape. Cruise still doesn't work either way.

Does it happen after driving awhile typically? Your last post sounds like the tank pickup is plugged...

I have a sump off the bottom of the tank. Irate reg return fuel bowl out there. Pre 10 micron water fuel sep and 2 micron post pump. And the fuel does cut out.
Today I dumped the the tranny fluid. It was like new,no burnt smell. Changed the pre filter and drained the post emptied it and reinstalled it. Had to order that one and will be in tomorrow. Now the transmission will go in OD just fine, but when I get down on the throttle it will hesitate and and and won't go back to OD till you stop and turn it off, then it cranks up and runs fine as long as you don't dog it.

79jasper said:

Sounds like the tc is unlocking.

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Click to expand...

Tomorrow I have a guy down the road that scan my PCM to see if it's throwing any codes. I've read where the speed sensor on rear differential may need cleaning off or replacing,and transmission speed sensor may cause this issue. Maybe since I changed the fluid the TC is locking up under normal driving but releases after hard acceleration? I'm thinking it's a mechanical issue. Just so happens I have 2 months left under warranty. If this is the case what's the best solution to keep this from happening again? Billet TC with triple disc? I just need to know a lil more about this issue when talking to the transmission builder. It's a HD built tranny and I'm pretty sure the TC is a Ford motor home TC.

I finally got in the shop today. It's throwing 1747 code. Solenoid pack in the tranny. There's transmission fluid leaking from the electrical connector to the pcm. There seems to be no wires damaged. I contacted the company that I bought the transmission from and the tech is supposed to send me a troubleshooting guide to go by to see if it's the pcm. I've found a link that explains how to see if it's the pcm or the tranny. I also asked him about having issues pulling from dead stop on an incline while hauling a load, I thought it was the tc not locking up but I've learned it don't lock up till 2nd gear. However the stall in the tc would cause this problem. My mechanic suggest a billet triple disc as some on here have suggested. Anyways hopefully this can be fixed soon I'm stuck in GA and need to be on the road to Ohio for work. And back home for Christmas

Ok today I i got to trouble shoot the epc sensor. From the 81 pin at the pcm pin out to the epc plugged in the circuit was open. With the pcm plugged in and key on testing resistance from wh/y wire point at plug resistance varied from dead short to 900 something ohms. What I found was a very fine slit in that wire 4" from the plug at the tranny. I covered it and closed it up plugged it in. I still haven't haven't got the cruise to work yet. Changed the speed sensor at rear differential cause it had a lot of slop to it. So today I unplugged the brake pressure switch at master cylinder and cleaned it out with alcohol and put a jumper in it to see if that would make it work. When I cranked the truck it idled high then dropped lower than normal and back to normal. At first it wouldn't go in OD but after a few miles it did. I stopped a couple times turned off and started up and did ok but the idle issue was there. Took out the jumper plugged in and idle after start was normal and transmission was normal. My glo plug relay isn't working. And I have 12v from starter,12v from switch,9.6v to the pcm. Nothing back on to the relays. I think there is 2 or 3 inline fuses from the pcm to thesolenoid and it appears I have one blown. Anyone know where they might be?

No in line fuses. There are fusible links though.
Trace the power wires from the gpr back to the fender. You'll find them.

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I was jumping the relay out to crank it one morning and I accidentally hit that terminsl with 12v. I'm not really sure how the circuit goes but I'm assuming it goes from the switch to relay and across to the pcm and pcm reads bar pressure and eot and then sends to relay to close circuit for glo plug power. Or maybe when I've jumpered it out it may have sent voltage back thru blowing a diode in the pcm. I took the the cover off today and didn't see anything burned. But I suppose it could be weak. I'm not an electronics person but I'm ok on D.C. Circuitry. A lot more aggravating than a/c which is my profession. It's funny though how p1747 is connected to epc,glo glo plug relay and cruise. What's the similarity there?

The pcm grounds the relay to activate it. Then it receives 12v+ when it's off. So I don't think it would've hurt the pcm, but then again, I guess it could. Lol
Do you have 12v on the power side of the gpr?

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