Starting to pull my hair out on this one.

Truck is in my signature except the timing is at 16*.

TPS voltage set at 1.1 volts.
Converter lockup switch installed like this: http://www.thedieselgarage.com/forum...9&d=1204352931
470 Microfarad 35 volt dc capacitor spliced into the TPS harness between the orange and black wires.
RF filters clamped onto the wires from the alternator.



These are all fixes I've seen either here or on other forums.

What the truck does..........

Shifts into 2nd and 3rd just fine. Doesn't go to OD until over 50 MPH, which is about 2500 RPM in 3rd. Converter locks in OD shortly after it goes into OD.

When decelerating, the converter will remain locked until it gets under the speed where it locks up on acceleration. If you use the brakes to slow down, the converter will unlock when you hit the brakes, but then it will lock up again in a couple of seconds until you are going slower than the lockup speed.

I do not have an aftermarket transmission controller of any kind on the truck. Nothing like a Co-Pilot or the like.


I will make an appointment to get the truck on a scanner next week if I can't get this resolved sooner.


By the way, the shifts feel good, the converter feels good, no slipping that I can sense. Seems to be a control problem more than a transmission problem.


Am I going to have to buy a new TPS or what?


Thanks for any help,
Chad

 

Please don't tell me I've stumped the gods!


Anyone?

 

I don't think that I can be of much help, but here goes nothing. What is the voltage on the tps on WOT? It is supposed to be 2.2-2.9 volts higher than at idle. Is your linkage measurement from center of ball to rear face of bracket 5"? Did this happen right after you installed the lock up switch or did it work fine after the switch install?

 

Try lowering your TP voltage at idle to .8v. I've had a couple I had to set even lower than that to fix the late shift. You'll have to adjust the rod length to adjust the voltage.

 

I did that drawing. The resistor so there is no codes and the relay so as the led light would work on the switch. My truck has the stock TPS and the shifts are fine as well as the lock up. when the switch is off and the ecm is controlling lock and unlock it seems to be fine as soon as I let off the throttle it will unlock get back on it, it locks.

Why the capacitor? if you want to adjust the lock up would a rheostat not be needed so as the resistance could be altered. A capacitor is basically a storage device. Other than that not sure.

 

Not sure why the capacitor. I read on a BBS that it can trick a troublsome TPS into working correctly. I took it out tonight, and there was no change. Same with the RF filters. Took them out and no change.

Not sure what my TPS voltage is at WOT, but when I had the meter on it, it had a nice linear voltage increase all the way to WOT.

As far as the .8 volts, I've tried this thing at all kinds of settings, and it will work good for a bit, then go south on me again.

I will unhook the jumper wire from the converter lockup wire to the relay tomorrow and see what happens.

As far as if this started before or after the switch was installed, I'm not ure exactly. It has given me trouble for quite a while, as far as what speed it will lock, and whether it will lock up on deceleration. The switch has been in for a coupple of weeks, and nothing went really haywire until this weekend.
It sed to be unpredictable as to when it would lock up. Now, it won't lock in third gear (unless I use the switch), and won't go into fourth untill close to 60 MPH.

Stupid automatics. Don't make me get out my wallet. I've already spent more than enough on this thing for the small amount of power I make.


Thanks for the replies folks!

Keep them coming.

 

Found it, and fixed it! I think.

When I slotted the holes in my TPS, I removed and discarded the metal sleeves that were in the holes. When I installed it at some point, I over-tightened the mounting bolts, apparently smashing the TPS against the mount too tight.
What was happening was the TPS would get adjusted to voltage I wanted, then I'd tighten the bolts. (too much torque)
Everything would be cool for a short while, and then the TPS would stick at WOT position because it was too tight to let the spring inside return the switch to lower settings.

I found this when I had the scanner plugged into the dash port. With the key in the "on" position, my TPS was reading almost 4 volts. As soon as I loosened the bolts a little, it dropped.