converter wont stay locked

[buick83-T]

Have a problem my car wants to constantly unlock and lock the converter when cruising.....(have no trouble codes)...converter is the 2800 stall that poston sells..anyone had trouble with this converter doing this?........also put in new TCC solinoid still the same no change?

 

[pracingrev1140]

hi ,not sure if this would apply to your situation. i had a stock chip ,that made my car do the same thing. just cruising down the road. a nd the convertor would unlock, and then lock back up .changed the chip and that solved the problem, hope this helps RR

 

[buick83-T]

This is a 83 T-type....carburated..

 

[GN SBS]

I had an odd cause of this problem a while back-- let me share. I was using the larger filter (from a 400?) and it was just barely in contact with the 3rd gear switch. The intermittant grounding would cause the car to feel just like the converter was locking and unlocking rapidly.

You can see this if you have access to direct scan-- the 3rd gear indicator will rapidly flash on and off.

Since you've replaced the TCC solenoid, I'd drop the trans pan and check to see that the filter isn't bumping anything that it shouldn't be touching.

Good luck!
Scott

 

[buick83-T]

I have used a OTC 2000 scan tool and can watch the TC lock and unlock im sure its the converter.....

Can adjusting the tv cable cause it to unlock and lock differently?

 

[buick83-T]

Anyone?

 

[b4black]

Check your TPS at cold idle and see where it's at. It should be about 1.45 mV if IRC. If it's too low, the ECM will think your'e decelerating and unlock the TCC. Probably happens about 45ish MPH. Try putting it into D when cruising this slow.

Somebody suggested that my TPS reading was too high, so I lowered it. I noticed it locking and unlocking more often on the highway. Trans took a dump soon after. Maybe it was just a coincidence.

I hooked up a light to tell me when the TCC is locked and put it in the temp warning light socket (since we have a gauge). I also added a switch to force lock up at the track. Easy to do with the brown "F" wire at the ALDL connecter. It goes to ground when the ECM commands lock up.

PS - did you recently change tire size? It might have lowered you cruise RPM, so what use to happen at ~45 mph now happens at 50-55.

 

[buick83-T]

Rich,
tps is set at 1.20v warm....not sure of cold......

 

[b4black]

On the p-side of the carb are idle stops. Which one is applied usually depends on the engine temp (more correctly the choke position). Anyways, the TPS setting depends on which idle stop is applied. You can either push them by hand, or assume it's on the high stop when completely cold.

I found the old thread (glad it's still here!):
http://www.turbobuick.com/forums/showthread.php?s=&threadid=43985&highlight=TPS

 

[buick83-T]

RICH,
tires are larger than stock(205/70/14) but its hasnt been doing like this before which I havent really drove much on the highway where i would have noticed this.

Noticed that it is also locking too early like when i slow down and then start to accelerate it will lock-up when accelerating(KILLS the power real bad makes car sluggish)

 

[b4black]

I don't think your problem is in the trans since you can watch the ECM commanding it on and off. The ECM must be misinterpreting something. If the TPS sensor checks out OK, the next sensor I would check is the VSS. With the 2000, make sure it's reading close to the speedometer. Check the coolant temp while your at it also.

Somethng must be off and confusing the ECM.


PS - Maybe the TPS has a "dead zone". With the scan tool, work the throttle thru the range and make sure the TPS rises smoothly. It the voltage drops or spikes, this could be the problem.

 

[Ttype83]

My car does this as well.
I'm running that size tire size, but with a speed gear for 26" tires.

How is your vac Hg during driving?

Noticed that it is also locking too early like when i slow down and then start to accelerate it will lock-up when accelerating(KILLS the power real bad makes car sluggish)

Does it only do this after a hard drive?

The TV cable should only change the way it shifts and the TCC lock-up I believe.

What no Trans Techs helping here anymore?

Jim

 

[buick83-T]

4th gear pressure switch

T-type83,
Vac Hg is good(no leaks)...14 drive...19-20 park......
Does it all the time hard or easy driving

I just have asked a transmission guy the other day about it and was told it was the "4th gear pressure switch". He said it was a common problem on the early(81-83 200-4r transmissions) Guess ill try it and see if this cures it

 

[b4black]

That makes sense. I forgot about the 3rd and 4th pressure switches being inputs to the ECM.

The scan should display if the ECM it getting the switch signals.

 

[buick83-T]

4th gear pressure switch

Replaced the 4th gear pressure switch and problem is still there. Dont know what else could be doing this. Temp is running in the 167-170 area while cruising. Speedomter is off alittle(around 10 mph)But would that cause it to rapidly jerk the car.Anyone know what it could be doing this??? This thing is getting very irritating.

 

[buick83-T]

Anyone???

 

[b4black]

10 mph may be enough to case probelms depending if it's off high or low. At 50 mph mine locks/unlocks often. At 60 it doesn't. But I think this is more TPS related than VSS.

It's too bad none of the many transmission experts have chimed in. It's a 200-4R just like the SFI cars. Maybe the folks at www.montecarloss.com or another TR board would have some advice.

 

[b4black]

Rich,
He (buick-83T) is running a BFR trans. When he changed out the TCC did he use a 200R4 TCC or a 700R4 TCC? If he used a 700 he needed to install the shimes in it. He may also have a cloged/dirt hole for the TCC??? not sure of that one.
He should start by setting the TPS to .77 and going up from there.

Did he change out the TCC plug from the old trans to the new one?

Does it still have the speedo gears for 26" tall tires?

Jim

 

[buick83-T]

The TCC solinoid was correct for the 200-4r. I have not changed the speedometer gear for the 26" tall tires. Will have that done soon.

Have another idea that was suggested to check...the brake switch...i was told it could be right on the edge of clicking on and off and can cause this.

 

[b4black]

The brake switch cuts the power to the TCC. The ECM swicthes the ground. Both need to be closed to complete the circuit

The brake switch would cause lock/unlocking of the TCC, but the scan tool would still show what the ECM is trying to do. In this case, you would feel the TCC unlock, but the tool would display it as staying locked. (hope this makes sense!)

Regardless, might as well check the switch.

I wonder if a mis-adjusted the park/neutral switch would cause problems. Do your reverse lights work correctly?