Hi everyone,
I am new to this board and to TR in general. I have always owned high performance GM's but this is my first TR. Anyway, to get to the problem. As I was driving down the highway, I noticed that at around 75mph the car was spinning around 3200rpm. I didnt think much of it but then I drove my brothers GN and saw his was only turning around 2400rpm at the same speed. His car is an 87 GN and mine is an 87 T-type. Mine has an open rear and his is a posi. Both cars are low mileage and stock. What would cause this? Could have a previous owner changed the converter to a non-locking unit? Would a non-lockup even work in that car? How could I test it to figure out the problem? Any thoughts on this would be greatly appreciated. Thanks everyone,
Dan
Not to insult you but were you in 4th gear when you were driving both cars? Yes a non-lock up will work. When testing you should be able to feel the converter lock in or the easy way is to get yourself a scan tool. The OTC 2000 and 4000 tell you when the TTC is engaged.
I did make sure both cars were in overdrive. My car is a column shift and his is a floor shift but yes both were in overdrive. I saw a way to activate the lockup solonoid on the transmision by using a jumper between two terminals on the scan plug. If I did that, would I be able to hear the solonoid click? I am pretty sure that its not locking up. It was a cop car at one point in time, im wondering if they just replaced the converter with a non-locking converter since you say it is possible to do. I really want the thing to lock, maybe I will get a little better gas milage...lol
Another thing that hasn't been mentioned is the factory rpm gauge isn't very accurate. A scantool will be able to tell you the correct rpm of the motor. A way I have checked to see if mine is locking up is I just listen to the rpms. You should hear the car shift 1-2, then 2-3, then 3-4 and then you should hear one more drop in rpm, I think somewhere around 45mph. As far as the car being a cop car, I'd hate to have been whereever that thing was patrolling.;) I don't think they would have went to a non-lockup though, I would think they would stay with factory original parts for the reliability and warranty. It may have low miles but being a police car, they may have been very hard miles, so my guess would be the tach is off.
I personal would not use a jumper in the scan plug. Is your car currently using a stock chip? The reason I ask is...the stock chip is programmed to have the TTC lock in about 20 MPH. You can feel it lock (when locking the car does this weird jolt, hard to put into words). When engaged, giving the car some throttle it will feel like the car is bogging until there is enough throttle to disengage TTC. Then the car will suddenly accelerate. The stock chip is programmed this way to increase mileage.
Ok, I have replaced the factory RPM gauge with another factory rpm gauge because mine was reading way off. It was reading about double the RPM that the engine was actually spinning. As for the chip. The car is completely stock to my knowledge except for the K&N filter and breather bypass I put on it. The wastegate was never even messed with. None of the normal tricks that are done to these cars have been done, so I doubt that there is a chip in it. I can say after driving it again last night that the converter is without a doubt, not locking. I am sure of it. I can feel it shift every gear 1-4 but no lock. Now I need to figure out why its not locking. I really think that someone, probably the police dept. put a non locking converter in it. If thats not the case, then it has to be the TCC solonoid. I am not sure how to check either though. I will have to mess with it some more. Is a non locking converter cheaper than a locking, if it is, that would fit the police profile on repairs.
Dan
"noticed that at around 75mph the car was spinning around 3200rpm. I didnt think much of it but then I drove my brothers GN and saw his was only turning around 2400rpm at the same speed."
There can't be that much of a difference in RPM with lockup vs. non-lockup. Generally it is around 200-400 RPM, but no more. The best way to check if it's locked up is to get the car to 50 MPH, then tap the brake slightly without releasing the throttle...you should see the tach increase 200-300 RPM, then decrease within a second or two. If the brake switch is not set properly, your lockup feed will not get the required 12 volts. Look at the purple wire in cavity A on the TCC connector at the transmission, it should be 12 volts with the key on, then go to zero volts when you hit the brake pedal. If that doesn't get the required voltage, the torque converter won't lock. And don't trust the factory tach. It is a common problem with them going out of calibration. We can calibrate the modules if you need.
-John Spina
http://www.casperselectronics.com
Ok, all fixed. Last night I replaced a rear brake line, I had to bleed the brakes excessivly. Today when I started driving it, the TCC engaged, I felt it. It must have been something with the brakes, the switch you were talking about. I dont really care what it was, just happy its working. I was getting around 20mpg before, may go up to 22 or so....with gas prices what they are, I hope so. Thanks to all who contributed with my dilema. If I can ever help any of you, I sure will try. Thanks again.
Dan
87 T-type (cop car)
The switch he was talking about, and probably what caused the problem, is under the dash. I think there are two down there, one for the brake lights and the other is for the TCC. I forgot that switch was down there.
From what I remember there isn't anything that really locks those switches in place, like if you pull up on the pedal, you'll move the switch which can make your brake lights stay on. It took me a few minutes to figure out why they wouldn't shut off. Glad you fixed it, how about some more details on the cop car? Scott
87 GN (Never been chased by a cop car, yet, as far as I know ;).)
my torque converter hasn't been locking up either on my 84 and i have had that switch pop out and kill my battery several times.... is it the top or bottom one that controlls it th TC?
thanks,
james fowler