1990 transmission

[Casal]

Hello everybody, I'm from Switzerland
and I'm a fresh new owner of a 1990 Pontiac
Trans sport. I really enjoy this car, seem's like
a toon! Is a 3,1L V6 with 3 speed auto-trans
But last day, I was on a coasty road and the engine
shout off. so I starded and engage the shifter to D
then the engine stop... and again, and again...
Finally, the car start and the probleme din't come...
Any idee?
Thanks for your time, and have fun over sea

[alex-sweden]

test vacuum line,and egr-valve

[Casal]

With this connector not connected, the
trans don's stop the engine.
What is this connector?
Thanks

[trannyman52]

that plug controls the torque converter lock circuit,,,,,there is a solenoid
on the valve body that should be replaced,,,,,,you can run it like that ,,,but the gas mileage REALLY goes down the toilet!!!!!

[Ektalog]

Originally Posted by trannyman52

that plug controls the torque converter lock circuit,,,,,there is a solenoid
on the valve body that should be replaced,,,,,,you can run it like that ,,,but the gas mileage REALLY goes down the toilet!!!!!

Yep, that's it, most of the time. Another symptom of it is that as you slow down to a stop, the car starts to feel as when you leave a manual shift car's clutch engaged as you stop...violent jerky movements. In fact, that is what is happening. The "lock" is like a clutch. Except it only engages past 45 mph or so to reduce slippage and improve fuel economy. When the solenoid fails to disengage it at low speed, as it should, it stays locked until the car stalls in a stop.

Leave the connector off until you replace the solenoid. My Silhouette, same year and engine, dropped from 21mpg city to 18 average while I had it disconnected.

Edit to add comment:
hmmm...I just thought of something else. When I read your first post, the torque converter didn't seem as a top suspect to me. In fact, it was only your next posting that convinced me that it was the issue. However, it may just be ONE of the issues.

If the engine stopped while powered at 50mph+, other things may also be happening (although "coasty road" may mean curvy/downhill?).

Let me cut to the chase and suggest this: Unless it has been done recently: replace the ignition coil and the ignition module. A flameout on the road at high speed is not fun. The ignition module has a nasty habit of doing this as it is about to totally fail (then car won't start again) -- a behavior similar to what your first posting sounds like. These parts are easy to replace (critically, make sure the heat transfer paste is used per the instructions for the module). Even if not involved in your current problem, these parts should be replaced in cars of this vintage (if they haven't already, which is hard to know if you are not the original owner).

Good luck!

[Casal]

thanks a lot
I will receive the Trans Sport Shop Manual in the
next few day from Helminc.
I have a same book for my Lincoln Mark VIII,
and that "bible" will be helpfull and a source
of "How-To" secret...
have fun