I have a 92' power wagon 250 with the 5.9L 12V intercooled, A/C, power windows, locks, and lots of electrical problems! My biggest problem right now however is that my over drive will disengage at speeds of 75MPH or not engage at all. I noticed that the problem happens when it's moist or wet out although it still occurs when everything is bone dry, also the tachometer will not read true or not give a reading at all while the problem is happening. But if i step on the brakes the tachometer will work but it still wont shift. my battery voltage drops a considerable amount as well sometimes down to 10V, all these problems come and go at the same time. please help!! I bought a book for the truck but it's useless. (no diesel info at all)

Those wires are corroded enough aren't they What voltages do you get when the truck has sat all night (drained residual voltage)? What voltage do you get with it running but not messing up?

There is no drained residual voltage, before start up there is 12.2V and during cold running operation there is 14.1V If i floor it and keep it pinned for about 3 sec just before it's at full temp it will get a voltage drop and stay there at about 12.1V

You mean before it screws up, and only when you floor it, it drops to 12.1?

Before starting voltage 12.2V just after starting voltage 14.1V (with no grid heater). If i floor it just before the engine has reached temp it will screw up (12.1V) and stay that way tell it cools down

So if you floor it, or if it gets to operating temp, it screws up? Hmmmm

Ya it's kinda strange, I'm thinking about unhooking the trans temp sensor and trying it like maybe see what happens:shrug:So i unhooked the sensor and it wouldn't shift into O.D at all cold or hot. I also started the rewiring process, I'm starting from the inside out, there is no longer a dash in my truck at the moment making a custom one as i type, most likely going to be covered in purple heart lilac. Also there will no longer be a radio, seeing as how i don't listen to music while i drive and more then 16 wires are used just for it's function.

I'm thinking it would take as much time rewiring it as it would to find this interesting problem. Not to mention I am not an automatic trans expert by any means so there could be more causes than I am thinking that cause this problem. Your truck is very simple though so I think theres just some bare wires somewhere. I still can't understand the only when you floor it or gets to operating temp thing. Still thinking though..

I would have to agree with that, it probably will be quicker to just rewire the whole thing. And i actually hate autos i wanted a standard but i only found 2 of these trucks in Ontario and both were autos Maybe once i get the cash together I'll drop a Mercedes 6 speed in her, i heard they make one that will bolt up. For now I'm going to just keep plugging away at this wiring, it's day two and i have a crap load of pics to go through and post for you guys, including the start of the dash:thumb1:

You have more motivation than anyone else I know. Keep working on it! Be neat to see those pics. Take your time and make it all look nice.

The TPS (throttle position sensor $250 ) is a good possible for part of this,The PCM grounds the lead from the OD shift connector at the top rear drivers side of the transmission. Turn the ign on engine off and see which has 12v and add a switch to ground on the other to prove the transmission is working right. I stopped there but a 5k ohm pot will fool the PCM and let it work near original - it replaces the TPS and is inside the cab.

sorry about the lack of posts i've been pounding out that dash it's almost done just need to do the fine tuned details (wood, leather work) i put some pics up for your viewing pleasure. And if i understand this right i send a 12v signal to the trans positive side of that connector and it should go into OD right? or i can bypas the TPS with a 5k ohm resistor?

Very nice looking dash! Takes a lot of skill to do something like that I am pretty sure the 12v being sent does lock the tc, not sure but my ford was the same way. As for the TPS, no idea. Keep working at it!

i think i might just put a manual OD for the time being. As for the talent side of things this is my first time using auto body hammers although i have a very good feel for working metal. i can't wait to get her all finished up (haven't drove it in about 2 weeks now)

Here are some more pics of the dash, if you guys have any questions on how i did something feel free to ask

Wow!

I temporarily installed the dash today and i got the O/D problem fixed (manual activation), but now as always the little unforeseen problems have to get weeded out (mostly electrical) and i had a good scare today when my oil pressure line popped off and i didn't notice tell there was almost no oil left, only about 3/16" from the end of the dip stick i think the pump was still able to grab it from the pan though. if they made those stuped hoses so that they don't break when kinked that whole problem could have been avoided:mad: I'm getting newer better hose tomorrow!

I had something like that happen when I welded my downpipe. I put the ground on the exhaust manifold and I guess I bumped it and it hit the steel braiding on the turbo oil line and since that was then the more direct line of current, it arced and burnt a hole in the line. Little did I know... So I start it up and watch this jet stream of oil shooting out the line Good thing my hood was open so I could see it and turn it off that instant. Your hoses might just be so old that they crack if you breath on them lol

that was actually the first thing i put on the truck when i bought it about 6weeks ago lol i kinked the hose when i was plumbing it threw the cab and it broke so i used a ton of shrink wrap and it held untell the oil seeped in and let it slide off I found the cause of all my problems as well it was the pcm that some genius decided to put in the 1/4 panel, and of course my wheel wells are rusted out and the silicon was all cracked and dried witch let moister corrode the PCB (printed circuit board) I'm not putting it back in, it's useless in my opinion considering i got my manual O/D now, so i get to start what i like to call "lawn mower wiring" no fancy circuits or auto bullsh!t. Everything is going to be manual or none existent. O and here is a pic of the dash in the truck

So it turns out that after 18yrs the silicon on the ECM had dried to the point of cracking, upon further inspection (removal of old silicon) i found that about 45% of the board had carrode and/or delaminated! probably something to do with extreme hot/cold weather and road salt Anyways it turns out nothing was shorting out, it just wasn't getting a single to function e.g. gauges, alt, O.D, ect. As for the dash i have a couple of teasers for all you boys and girls to look at, a pictures worth a thousand words and i don't feel like typing that much

Dannng! You cook, you sew, you make a dash that looks better than stock, what can't you do! I want to see this thing finished