This MLPS issue pops up from time to time. The research I have done indicate the pin-out on the old versus new MLPS is the same. Although years ago Diesel_Brad had a problem when installing the newer MLPS on one of his trucks. I posted a link in this thread from another forum: Repinning mlps connector to 95 style - FSB Forums

In reference to Brad's issue I think his was on a 1994 Lightning. Perhaps Ford had a whacky E4OD wiring scheme for that model year only?

Bill is known to have more than a few surprises up his sleeve from time to time to confirm or debunk a theory.

 

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Sorry for such a late response. I have not forgot about this thread, Ive been pretty busy with work.

Truckin Bob: I dont know why the pinout would have changed, I never touched it, no codes on the computer. The trans was never rebuilt, this happened whithin the last couple of months. Only thing I have done was flush the fluid a year ago, and put in Lucas tranny fix about the same time because reverse was slipping a little

Reverse doesnt seem to slip now but it locks the converter (or feels like its locking) drops the rpms and shutters, usually kills the engine. Also the forward shifts are neck breaking somtimes, if you feather the pedal you can get it to shift OK, sometimes.

I tempted to take it to a good trans shop to get their opinion, or...very sad though, of letting the truck go to use the cash to put in my torino race car, and 70 cougar.

 

Gotcha' on the pin-out thing.....nix that idea.

"Reverse doesnt seem to slip now but it locks the converter (or feels like its locking) drops the rpms and shutters, usually kills the engine."

That sounds like the trans filter has dropped down into the trans pan.
Classic symptom.

Bob

 

Alright, looks like I'll be dropping the pan this weekend. Ive been hesitant, but man what good feeling it will be if I see that filter laying in the pan

Thanks guys, I'll give updates soon as I can.

 

Do a little searching for a "retainer devise" that is suppoose to keep the filter from dropping down unwantedly into the pan again.

It's out there, I've read about it, but don't remember what it's called or who sells it.

Might be worth the investment.

Fingers are crossed for you,

Bob

 

Got up this morning and dropped the tranny pan. The filter was a little loose but had not fallen off. I cleaned it up, and made a bracket to help hold the filter on.

Filled it back up, let it warm up then took it for a ride. Right off shifts we're smooth, reverse felt normal. I put it in and out of reverse a few times with no issue. It was about a quart low so I drove it up to the auto store to add in a quart. Fluid was on the fill line, after a quart, again fluid was all the way up the stick, like it was overfilled...I CANNOT get a good reading of fluid on this damn thing.

Decided to take it for a drive, about 10 minutes of running errands, all happy I had fixed it, went to pull out of a parking lot in reverse and it slammed in reverse and killed the motor...

Thought I had it. I then took it all the way to decatur, one hour one way trip. It seemed to shift decent, still very firm. Reverse killed it up there too. It got me home safe though, freeway cruising is just fine.

Is the truck over filled?? I have a hard time believing that, but I cant get a good reading on the stick. I just thing the tranny is worn out...Truck has 232K miles on it, the engine is still GREAT though.

 

Alright, here goes.

You may have a leaking vacuum system.
How's the coffee cannister ????
Have you replaced the vacuum lines ???

The ford vacuum system is actually an "engineered metered" vacuum system dependent upon the coffee cannister vacuum reservoir.

If there isn't enough "stored vacuum" in the coffee cannister when you put the truck into reverse, the map sensor (assuming you have one) will recieve an incorrect value and send that "incorrect value" to the computer which controls the solenoid(s) which controll the internal transmission pump(s).

Your vacuum system has to function as "stock" in order for your transmission to shift correctly........assuming there isn't any thing wrong with the transmission.

Your problem could be as simple as a vacuum leak, incorrect vacuum hose sizing/metering, or a wrong vacuum source.

You need to check the complete vacuum system and get it operating as "stock".

I played with all of this last weekend.......so I guess I can rightfully say "been there done that".

Bob

 

Hmmm Intetesting. I will double check vacuume lines. Last summer I replaced the MAX AC vacuume line. I dont hear any leaks, and the trucks idles just fine. I will poke around and look for leaks as well as put on a vacuume gauge. What "should" vacuume at idle be? I'll check the canister closely too.

One thing I didnt mention was that the truck has been cranky to start. Once started it purrs fine. But it used to start right up. Truck has new plugs/wires/cap/distributor. The coil has not been replaced. But now when starting it cranks a good 4 to 5 seconds before starting.

I started noticing that around the same time the reverse issue popped up.

 

Now we're gettin' somewhere........

Bob

 

Could a vacuume leak cause sluggish starts? If it was a sensor causing the delyed starts wouldnt the computer throw a code, actually wouldnt a vacuume leak cause a lean condition that would also throw a code?

 

"Could a vacuume leak cause sluggish starts?"
Yes

"If it was a sensor causing the delyed starts wouldnt the computer throw a code"
It isn't a sensor thats causing a delayed start, it's a vacuum leak, or a leaking coffee cannister, or a stuck/sticking IAC valve, and no, it won't throw a code.

"wouldnt a vacuume leak cause a lean condition that would also throw a code?"
Probably not, the computer will tune itself (through the O2 sensor readings) as it's running (with the vacuum leak) by closing off flow (not all) from the EGR valve.
Unless there's a HUGE vacuum leak, the computer can adjust itself to run by closing off some of the airflow allowed in the manifold via the EGR valve.

I know this seems like it's getting complicated, but, you'll get there.

Bob

 

You are much help Bob, thank you for sticking with it with me.

 

You betcha'

I just want to see you get this resolved and enjoy your truck.
After all, that's why you have it (your truck) isn't it ????

You'll get there.

Bob

 

OK. SO, found a vacuum leak. There is a sensor that comes from the PCV valve to the coffee canister. It was rotten off. Also the hose directly to the PCV valve was leaking and loose, so I put a clamp on it. It had a noticble leak, I could hear it.

So then I drove it hard, romping it from 1st to second chirped the times, which is a good thing is I had a shift kit, but on 37" military times its not so good. Also, died a gain in reverse. Reverse feels like its locking up, shuttering and dropping the rpm. Just doesnt sound right in reverse. Could it be I need to reset the ECU?

i was SO STOKED! thought for sure I had found my issue. But it made little difference...I unplugged the battery, letting it sit then I'll take it for another round.