Won't start when warm

jeffa123 · 09-30-2005, 10:12 AM

1990 Buick Lasabre 3.8
This has been a great car with no problems. The car will always start cold. However, after it has been running the car will not always re-start until we wait. It got to the point where I couldn't start it after waiting, I took a gamble and replaced the ignition module. The car then started right up. However, a week later after I bought gas the car didn't want to start again. It then started on the fifth try. It did it again a few days later at home. after I tried to start it 10 min later. I checked for spark, with a plug wire and their was spark. Also, checked for fuel in the injection servo(valve) and there was fuel pressure. I checked the trouble codes (field test) 21 showed. Throttle Position Sensor (TPS), voltage high. The engine cranks fine, the car just won't fire up when it's warm. Any idea's would be greatly appricated. My wife won't drive this car anymore. She's does not like waiting for it to start after stopping some place. The car seems better to me after replacing the ignition module. But it's still not right.

**guyopel** · 09-30-2005, 01:39 PM

One test you should try , when the car is at operating temp. tap on top of the coil pack ,if the eng. dies then replace coil pack ( internal short in the coil pack ) this was a common problem, when the coil shorts it fires into ing. module and car cuts off .There are more areas to look at but hey let's
do one at a time .. do the least expensive first

HTH Guyopel

Roadmonster · 09-30-2005, 10:59 PM

When you get the coil pack off look underneith for signs of arching. That will be the one.

jeffa123 · 10-01-2005, 04:30 PM

I drove the car 6 to 7 miles, then tapped on the coils with a screw-diver handle while ideling. Tapped on all three coils top and sides. I did this test twice(two different test). Car kept running fine.

When I changed the ignition control under the coils (see post above) I did not see any signs of sparking. however, the plastic on the old ignition control module had partially melted (the green insulative plastic on the module under the coils). It was sticky and kind of a pain to clean off the wires and connectors when installing the coil pack to the module(I wondered why that soft plastic had melted). I guess the heat over time would do that?

Also, I have been trying to get the car to fail to start again. Waiting 10 minutes. But the car has been starting when warm with no problem. I guess I need to let my wife drive It, so I will fail again.

**guyopel** · 10-01-2005, 07:44 PM

The condition on the ing. module is normal ( melted looking ) I use a small
hammer and TAP on the top of the coil pack where the rasised diag. part of the coil is .And only at this area, hope this is a better explanation .
Guyopel

jeffa123 · 10-02-2005, 08:22 PM

I tested the coils by tapping on them with a small hammer after the engine was warmed up to operating temp. (tested twice). The engine worked fine. I don't think there is a short in the coils.

The car didn't start after I turned the engine off and ran into the library today to drop off a book (5 MIN.). After I waited 5 Min. and three trys the engine started up. This also happened at the gas station.

Before I replaced the ignition module it would take 15 min. to 30 min. wait before the car would start when it was warm. Now it takes 3 to 5 min.

Thank You for you help.