Guidance given is pretty solid here although tough to diagnose from afar with the info given. I second the motion. Look for vacuum leaks, and check cold and hot fuel pressures. You'll need the pressures for baseline anyway. That should rule out engine side issues.
Does the engine buck or run rough right before it dies? If not, it could very well be the TCC solenoid. Do Turbo 6's have knock sensors? I'm not fluent in hair dryer application engines. Knock sensors may change how the engine reacts.
Sometimes the solenoid sticks and keeps the converter clutch engaged. When you roll to a stop, the engine still wants to turn the back wheels. Drivetrain drags the engine down.
In 86 stock form, you should have a TCC solenoid for your 200-4R transmission. Buick T's IIRC, have a 4 wire setup on their driver side plug and they're wired upside down from the rest of the world. If you're not familiar where the plug is, look for it on the driver side where wires connect. Can't miss it. Again, not sure, so I can't be sure which wire goes where, but in certain conditions, the TCC solenoid energizes to lock the clutch on the converter. If sticking, it may seem to shift earlier.
Coming to a stop by stepping on the brake should instantly drop out the solenoid, or if you get out of the conditions for lockup. As soon as you can after starting it cold, go on the highway for a cruise at 60 or so, when the lockup is engaged. Maintain a steady speed, then tap your brakes lightly. You should see/hear/feel RPM increase as the TCC solenoid drops out and then RPM drop as it kicks in again. After it starts to die on you around town, do the same highway test again. No drop, then the solenoid is sticking.
Alternately, unplug that side plug on the side of the transmission. Then immediately drive it around again and make sure you can get it to lockup conditions where it should lock up. If the problem is "solved" after it's all heated up and no stalls, then it's likely the solenoid was sticking. There's also a 4th gear pressure switch inside too I believe, but this usually is not an issue. Don't forget to put the plug back.
8639900 is the TCC solenoid p/n from GM for those BR transmissions, but guess what? It's long discontinued. It's different than the others like Monte SS and H/O, 442. Easy to replace. Drop the pan, and it's in front of the filter. Just a few wires and 2 mounting bolts. You'll see it. Might as well do the filter while you're in there. Filter kit with gasket is GM p/n 8639951.
If you do determine it's the solenoid and go to replace it, make sure the o-ring is in place on the old one should you remove it. DO NOT throw out the old solenoid until you make sure the new one works and resolves your issue. If it's not the solenoid, those things are hard to find. So don't toss it until you're absolutely sure that was the problem child.
19139322 is the 'new' GM p/n, but it's a slightly different solenoid. Comes with little spacer studs though. Catalog says it fits 84-87 GN. But what do I know.
Then again, it may not be a solenoid problem. So don't go replacing parts that don't need it until you know you have to.
Does the engine buck or run rough right before it dies? If not, it could very well be the TCC solenoid. Do Turbo 6's have knock sensors? I'm not fluent in hair dryer application engines. Knock sensors may change how the engine reacts.
Sometimes the solenoid sticks and keeps the converter clutch engaged. When you roll to a stop, the engine still wants to turn the back wheels. Drivetrain drags the engine down.
In 86 stock form, you should have a TCC solenoid for your 200-4R transmission. Buick T's IIRC, have a 4 wire setup on their driver side plug and they're wired upside down from the rest of the world. If you're not familiar where the plug is, look for it on the driver side where wires connect. Can't miss it. Again, not sure, so I can't be sure which wire goes where, but in certain conditions, the TCC solenoid energizes to lock the clutch on the converter. If sticking, it may seem to shift earlier.
Coming to a stop by stepping on the brake should instantly drop out the solenoid, or if you get out of the conditions for lockup. As soon as you can after starting it cold, go on the highway for a cruise at 60 or so, when the lockup is engaged. Maintain a steady speed, then tap your brakes lightly. You should see/hear/feel RPM increase as the TCC solenoid drops out and then RPM drop as it kicks in again. After it starts to die on you around town, do the same highway test again. No drop, then the solenoid is sticking.
Alternately, unplug that side plug on the side of the transmission. Then immediately drive it around again and make sure you can get it to lockup conditions where it should lock up. If the problem is "solved" after it's all heated up and no stalls, then it's likely the solenoid was sticking. There's also a 4th gear pressure switch inside too I believe, but this usually is not an issue. Don't forget to put the plug back.
8639900 is the TCC solenoid p/n from GM for those BR transmissions, but guess what? It's long discontinued. It's different than the others like Monte SS and H/O, 442. Easy to replace. Drop the pan, and it's in front of the filter. Just a few wires and 2 mounting bolts. You'll see it. Might as well do the filter while you're in there. Filter kit with gasket is GM p/n 8639951.
If you do determine it's the solenoid and go to replace it, make sure the o-ring is in place on the old one should you remove it. DO NOT throw out the old solenoid until you make sure the new one works and resolves your issue. If it's not the solenoid, those things are hard to find. So don't toss it until you're absolutely sure that was the problem child.
19139322 is the 'new' GM p/n, but it's a slightly different solenoid. Comes with little spacer studs though. Catalog says it fits 84-87 GN. But what do I know.
Then again, it may not be a solenoid problem. So don't go replacing parts that don't need it until you know you have to.
