Converter locked up all the time...PCM???
11-14-2007, 12:09 PM
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Converter locked up all the time...PCM??? Hey guys, I have a 99 Trans Am A4 and just got the tranny rebuilt. Sun shell broke at about 125k miles. I had a local tranny shop rebuild it with a trans-go shift kit, pinless accumulators, beast sun shell, and all new wear parts. It worked great for about a week, nice firm shifts and no problems at all. Then this all started...The car started to "buck" when taking off from a stop and when shifting gears. The day after that, the torque converter was locked all the time. Whenever you put the car into gear, it would die. Torque converter was rebuilt by a local shop that's pretty reputable. Also had the tranny guy take it back apart to look for damage. He didn't find anything wrong, but replaced the entire wiring harness with a new one, as well as both solenoids. We put it all back in, and once again, it worked great for about a week. I noticed this morning on the way to work it started doing the bucking thing again. It pretty much feels like someone driving a stick that doesn't know how to drive a stick...Lurches and jumps. It hasn't started killing the engine again yet, but I noticed something else funky. This morning, it threw an SES light. I don't know what code yet because I'm still at work, but when I leave here, I'm going to rent a code scanner. Another weird thing...just as I pulled into work, I noticed the "check gauges" light went on...I looked, and the gas gauge was on E! I put the car in neutral to coast into the parking lot, and it went back up to about where it was before...Just under half a tank. Could the PCM be shot and sending signals to lock the converter when it shouldn't? I'm getting tired of pulling the tranny out of this thing, and if I can avoid it, that'd be great....Btw, the tc is a stock rebuilt unit...No big stall or anything. The car is pretty much stock, with a few bolt ons, nothing major.
Thanks for your help,
Jason
Thanks for your help,
Jason
11-14-2007, 02:48 PM
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Thanks for the quick response Performabuilt...Sorry it took me a while to get back to you, work's pretty hectic. Anyway, what can I do to rule out the PCM as the culprit before pulling the tranny?? The pump is brand new as well, which makes me think it's not the tc valve, but stranger things have happened, and anything's a possibility. The part that is really confusing me is the whole thing with the fuel level gauge...Could be a completely separate issue, but that seems unlikely to me. 
Appreciate the help.
Appreciate the help.
11-14-2007, 04:38 PM
#4
ok get and LED test lamp not a bulb must be the led type. Tap into the brown wire with the black stripe and hook the negative side of the test lamp to the wire and the other end to a 12 volt source. When the PCM comands the solenoid off the test light should be off when it comands it on the test light should be on , This will prove or disprove the PCM as the culprit. The wire can be found at the trans or at the PCM
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Last edited by performabuilt; 11-14-2007 at 07:16 PM.
11-14-2007, 07:15 PM
#6
I would drop the pan and pull the TCC solenoid out of the pump (2 -10mm bolts hold it in) and remove the screen from the solenoid. Make sure the screen is clean and not full of debris, if it's pluged the converter will stay on all the time because the solenoid needs to exhaust when not commanded on. Sounds like you have a converter clutch coming apart to me from your description. If your tcc screen is full of debris the trans needs to come out anyway. I doubt that your pcm is causing your problem.
11-16-2007, 10:35 AM
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Thanks for all the info guys. Haven't had a chance to do anything with the car yet, but I'm probably going to tackle it later tonight. One more question, if I cut the wire for the tcc, will that prevent the converter from locking up altogether?? If so, are there any drawbacks to doing that besides the loss in gas mileage? This whole project has me about ready to sell the car, which I don't want to do, but I've already pulled the tranny 3 times and probably spent 175 bucks on atf alone...getting kinda tired of it. Thanks.
-Jason
-Jason
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11-16-2007, 10:43 AM
#8
I would drop the pan and pull the TCC solenoid out of the pump (2 -10mm bolts hold it in) and remove the screen from the solenoid. Make sure the screen is clean and not full of debris, if it's pluged the converter will stay on all the time because the solenoid needs to exhaust when not commanded on. Sounds like you have a converter clutch coming apart to me from your description. If your tcc screen is full of debris the trans needs to come out anyway. I doubt that your pcm is causing your problem.
DO this 1st !!!!
Don't cut the wires. Remove the solenoid, then remove the filter and inspect it for debris just like Vince stated. This is a very common failure for the symptoms you described.
g
11-17-2007, 01:26 PM
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Okay, dropped the pan last night, pulled the tcc solenoid out. I think the converter clutch is coming apart, but not sure why. There was a fair amount of clutch material in the pan/filter. Replaced filter and added 4 quarts of fluid and a pint of Seafoam. It doesn't seem like it's locking up in 1st gear anymore, I laid about a 40 foot patch in the parking lot last night. But, when it shifts into second, it locks for a sec then it's ok. If I drive the car between about 30-45 mph in 4th it locks and starts lugging. If I put it in 3rd at the same speed it's fine because of the rpms. Even locked up it had plenty of torque to pull just fine. The torque converter, tranny, wiring harness, and tcc solenoid were all brand new about a week ago. I didn't find any problems with the wiring or PCM. Really getting frustrated at this point.
11-17-2007, 01:43 PM
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Thanks again performabuilt. One more quick question, if the tps sensor is bad, will the converter stay locked up? Just curious, saw another thread that said the converter won't unlock until a certain tps % is reached. I would assume that means if it was bad it'd stay locked, but maybe I'm wrong?? I know it's not supposed to lock in 3rd anyway, but...sigh, just shooting for the moon I guess. Oh, and...If some kind of gremlin was keeping the converter locked, it's probably pretty safe to say that's what smoked the clutch? Thanks for all your help, I'm probably going to take the car back to the builder Monday.
11-17-2007, 03:37 PM
#12
You are waaaaay over thinking this.
The torque converters' clutch has failed. New converter or not, that is the deal!
Take it back to the guys that built it, have them cut it open while you wait. (If they don't then you need a new converter shop) Have them show you the clutch and at that time determine why it failed.... poor workmanship, bonding process failed, poor material etc....
g
The torque converters' clutch has failed. New converter or not, that is the deal!
Take it back to the guys that built it, have them cut it open while you wait. (If they don't then you need a new converter shop) Have them show you the clutch and at that time determine why it failed.... poor workmanship, bonding process failed, poor material etc....
g
11-19-2007, 02:10 PM
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Update....
The car is back at the original tranny builder. Just got off the phone with him. He said that he didn't find anything wrong with the tcc. He did, however, say that to him, it felt like a "dead spot" in the engine caused by my K&N's oil
He told me he's going to clean off the MAF sensor and drive it without the filter in it. I insisted to him that it STALLED THE F'IN CAR, but he won't listen to me...wtf do I know. 
Anyway, I'm waiting for him to perform the magic of cleaning the mass air flow and somehow fixing the tcc in the process and then call me back. I'll keep you guys posted.
The car is back at the original tranny builder. Just got off the phone with him. He said that he didn't find anything wrong with the tcc. He did, however, say that to him, it felt like a "dead spot" in the engine caused by my K&N's oil
He told me he's going to clean off the MAF sensor and drive it without the filter in it. I insisted to him that it STALLED THE F'IN CAR, but he won't listen to me...wtf do I know. Anyway, I'm waiting for him to perform the magic of cleaning the mass air flow and somehow fixing the tcc in the process and then call me back. I'll keep you guys posted.
