1992 Fsuperduty E4OD question

[Kevin 007]

Truck in question is a 1992 F450 6.9l (engine has been swapped out at some point from a 7.3) 2wd, with a freshly installed new E4OD.

FIPL is set to 1.18V at idle and 4.0V at WOT with the key on and engine off
Tach works great
VSS works great, after replacing one that was a bit fluttery
Trans fluid is full and clean
No flashing OD light
Plugs and connectors on the main harness plug on trans and MLPS are tight and clean.

The transmission shifts very well, however; when the truck if first put into D, from park or neutral or R, it will not shift out of 1st on its own, I have to manually shift it to get it out of 1st, and then once the lever is back in D, it will shift up and down just fine all day from 1st to OD....until the lever is moved back to P, N or R. Then the trans won't shift out of 1st again on next attempt to drive. After I shift it manually, it will proceed to shift up and down fine again. It will act this way both when the truck is cold and hot.

Would this possibly be a bad MLPS? Or are there any other thoughts on what could be causing this?

Once its shifting on its own, it shifts great and does so consistently. Only other thing worth mentioning that's less then perfect, is the TC wont lock as early as it should once the trans is in 3rd or 4th. It requires some extra throttle input to get it to lock up and it will unlock as soon as I lighten up on the throttle.

Any thoughts would be great.
Thanks

 

[Thewespaul]

Do you have reverse lights when it reverse? Any hesitation going into gear? Any brake lights out? Mlps could be the cause

 

[david85]

It sure could be the MLPS. As mentioned, check for backup lights. Could be as simple as needing to be realigned.

Might also be worth trying to bring your base idle voltage down to 1V. The recommended range is 0.8-1.2V IIRC, so you are on the high end of that.

 

[Kevin 007]

No, there are no backup lights. Didn't even notice until you asked. So could that be a sign that its out of alignment? Its been some time since I aligned one. I will search the subject and read up on it to freshen up.
Ok I will adjust the FIPL to .8v. It actually was at .7 and it acted the same way, but with shifts that I felt were a bit too early for this hilly area. And then found a good spot at 1.18v. But I'll go back again for now to keep it at spec to just eliminate that as possibly having some effect

There is also no hesitation going into gear. Goes in firmly.

 

[david85]

Don't mess with the FILP sensor until verifying the MLPS is working right.

 

[Kevin 007]

The MLPS was out of adjustment by just a fraction of an inch. And that seemed to fix the problem. The truck will shift great now right off the bat, no more manual shifting on the first attempt of going up through the gears. Probably the best shifting E40D that I have driven. I left the FIPL at 1.18 for now as that's where it seems to shift the best.
Still having the TC not lock up until I am really buried into the throttle. Buried beyond where anyone would be in normal non abusive driving. Once I figure that out I will be really happy with this trans.

Another things to note is there is no sticking brake pedal causing the brake lights to stay on, causing the lack of lock up

 

[Sidewinded_idi]

The fipl adjustment will mess with your tc lockup. I towed very heavy regularly and liked mine set at 1.11.

 

[Kevin 007]

Ok good tip. So in theory, a lower V setting on the FIPL should cause the TC to lock earlier? I will try lowering it a bit and test drive. I'm a little concerned about the trans shifting too early then but we'll see how it goes.

 

[Kevin 007]

Yeah adjusted it lower but to no avail. TC still not locking as it should. Might be time for a manual lock up mod. I like the mod but the truck will be driven by a few different people so I'm hesitant to have the mod done on this truck

 

[Kevin 007]

Noticed tonight in the dark, that the brake lights are on very dimly when the key is in the ON position. They work properly when the pedal is depressed, but I now realize that they have been very dimly lit with the key ON. I'm betting that this is effecting the TC lock up issues. Will look into it in the daylight. No idea whats causing them to be dimly lit at this point.

 

[david85]

That could certainly do it. Check the brake light ground at the rear of the frame. If the ground is weak, it could be backfeeding through the bulb filaments.

I'm not sure on other years, but on my 1986, the ground is on the drivers side of the rear-most crossmember. Very rust prone area.

 

[Kevin 007]

Great tip, thanks!