Throttle posioning sensor

[lgettler]

Which way do I turn the TPS sensor to lower it from 1.1 to .95 or thereabouts, I am looking for a smoother shift as it pops my head if I stomp on it.

[Evel486]

Set to 0.8v at idle position. Adjust max travel screw to achieve 4.1v min @ WOT.

[M.L.S.C.]

0.8V is too low for an EEC-IV management system, IIRC it calls for 0.95V to 1.1V at idle and no more than 4.5V at WOT. That said, I think his issue is elsewhere, as the only thing that will make a factory E4OD shift like described is if the line pressure is jacked way up doe to the PCM detecting an issue and entering failure management mode. For comparison purposed my own E4OD shifts very fast and quite firm, but I have a shift kit in it and drilled accumulator passage openings in the separator plate, and even so she still don't try to dislocate my neck... She sure did if I had a resistor in the EPC harness to raise the line pressure way up tho, so I say it's not the FIPL that should be looked into, but the PCM.

[rsr911]

Originally Posted by M.L.S.C.

... She sure did if I had a resistor in the EPC harness to raise the line pressure way up tho, so I say it's not the FIPL that should be looked into, but the PCM.

Tell me about this resistor! Imagining a variable resistor to adjust shift firmness.

[M.L.S.C.]

You don't need to know about the resistor, it's evil, put in a real shift kit instead! lol

But I'll tell you anyways - if you cut one of the EPC wires in the trans harness, and install a resistor inline, you can "fool" the PCM into readjusting your line pressure - you do however end up with higher line pressure all the time, which can lead to all sorts of nasty failures inside the trans, from starving up the TCC lockup clutch to exploding clutch drums and what not - Mark Kovalsky was once explaining to me all the scary stuff that can happen from this mod, so do a search. I currently run no resistor, and my E4OD shifts better than ever due to the shift kit and new modulator valve and also the faster-applying accumulators.

[rsr911]

Originally Posted by M.L.S.C.

You don't need to know about the resistor, it's evil, put in a real shift kit instead! lol

But I'll tell you anyways - if you cut one of the EPC wires in the trans harness, and install a resistor inline, you can "fool" the PCM into readjusting your line pressure - you do however end up with higher line pressure all the time, which can lead to all sorts of nasty failures inside the trans, from starving up the TCC lockup clutch to exploding clutch drums and what not - Mark Kovalsky was once explaining to me all the scary stuff that can happen from this mod, so do a search. I currently run no resistor, and my E4OD shifts better than ever due to the shift kit and new modulator valve and also the faster-applying accumulators.

I know! Bad sensor(s) causing limp mode wrecked my old trans. A shift kit is in my future. I was just thinking a variable resistor would be nice or maybe a three way switch (normal and firm) what ohms, do you recall?

Anyway back to the topic at hand. Pull the codes! Simple most effective way of troubleshooting these trans. Back in the 80's when all this stuff was starting to come out I hated it but now that I'm used to it I tend to like fixing things a lot more. At least the diagnostics tend to lead you in the right direction. For the record my FIPL is set at about 1.07v and it shifts too soft for my liking, hence the reason a shift kit (and cooler) are on my list.

[M.L.S.C.]

Originally Posted by rsr911

I know! Bad sensor(s) causing limp mode wrecked my old trans. A shift kit is in my future. I was just thinking a variable resistor would be nice or maybe a three way switch (normal and firm) what ohms, do you recall?

I tried three - 10 ohms, 50 ohms, and 100 ohms. 10 didn't make much difference, and 100 is a murder on U-joints and transmission internals, but 50 seemed quite a decent setting. You'll need a power resisitor tho, the big fat ceramic type, not the small ones that go in electronic devices.

[rsr911]

Thanks M. I just so happen to have a 50 ceramic (among others) at work. It's a spare for a machine we got rid of a long time ago. I plan on a fluid flush and shift kit plus a cooler in the spring. Just about done setting up my TCC lockup mod as well.

My opinion of these trannies is getting better and better. At first I read a lot of horror stories on this forum about them grenading etc. Now I wonder how many where burned up due to bad sensors etc. When my old one went into full limp mode (2 and 3 manual only) it was really hard on the trans. Final failure was actually the front seal burned up probably due to all the heat. My torque converter was discolored to. I figure a scan with the code reader should be part of regular maintenance, like after an oil change for example. It only takes a few minutes and replacing a 30 sensor could save your trans.