Engine/Transmission (1994 - 1998) Torque Converter Question

[SHaven]

My brother just bought a 1994 2wd. When accelerating from a slow speed, the torque converter locks up but kicks back out quicklyif you quit accelerating, then stays unlocked unless you stomp on it again. The overdrive works fine. He said that it will stay locked up at high speeds (80+). Any ideas on what might be faulty would be appreciated.

 

[Howard Durand]

Probably the throttle position sensor.



You can read a number of posts about the TPS that are devoted to various remedies to repair the existing TPS or for complete TPS replacement.

One trick that you might try (I don't think anyone has done this before). Remove tlhe TPS but leave it connected to the wiring. Rotate the moving part about half to two thirds of it's full rotation and clamp it tight with a small "C" clamp.

Take it for a drive. OD should shift normally, maybe at a higher speed than normal but the TC should lock up shortly after the OD shift.

If that is the case, the TPS is probably bad or contaminated.



Then you can read about total TPS replacement which, in my opinion, is the only way to go.

 

[SHaven]

Thanks for your reply, will check TPS and hopefully that will fix it.

 

[Howard Durand]

Most TPS problems appear to be caused by erratic information from the device itself. It is nothing more than a variable resistor and the wiper moves inside the case as throttle is advanced.

The PCM likes to see a smooth change in signal as the throttle changes. If the signal becomes intermittent or erratic, the PCM gets confused and starts messing with OD and the TC.

The filters that can be purchased to prevent that aren't always successful.

In my opinion, the best solution is to completely replace the TPS with either a potentiometer or a multi position switch and a handful of resistors. This method applies a set voltage to the PCM all of the time. This makes it possible to determine at what vehicle speed you want OD to engage.

TC lockup follows shortly after that.

Everything has it's plusses and minuses but it is worth considering.



Howard

 

[tgrfan2]

My brother just bought a 1994 2wd. When accelerating from a slow speed, the torque converter locks up but kicks back out quicklyif you quit accelerating, then stays unlocked unless you stomp on it again. The overdrive works fine. He said that it will stay locked up at high speeds (80+). Any ideas on what might be faulty would be appreciated.

The TPS in my 95 always acted worse cruising at 65-75 mph and especially on damp days. It shifted better after the throttle cable recall, but would still do the "in and out" sometimes.

I started spraying it with WD 40 at each oil change and it is still working at 240K. I just use a tube to direct the spray to the TPS shaft and work the throtte as I spray.

Worth a try. Good luck!