Problem with TCC coming and going.
Thread Starter
Senior Member
Joined: Jul 1999
Posts: 786
Likes: 2
From: Guilford, NY
Car: 1988 IROC-Z
Engine: 350 TPI
Transmission: 700R4 w/TransGo
Axle/Gears: BW 9-bolt w/3.73s
Problem with TCC coming and going.
I run my car over the weekend to a cruise-in and car show, over a nice hilly decent road.
One time I was in fourth going up hill about 60, and I noticed the TCC was pulling in and out, kind of like a surge condition. I know it didn't kick down to 3rd, since I manually shifted down and the rpm went up higher. I was giving it a little gas to maintain speed up the hill.
Amother time I was going around 50 up the hill and the TCC was also surging.
I have the TCC unlock prevent set at 60, and I lock/unlock the TCC in 4th at 50/45. Are these settings too high? I also noticed that GM had the difference between lock and unlock set at 2mph. This was consistent for many different bins. I don't think I hit the tables for unlock/lock for %TPS vs mph, since I didn't think I gave it enough throttle at those speeds. But I could be wrong since I didn't have my scan tool connected.
Today I scanned on the way to work, and no surge condtions were observed, so it seems to related to maintaining speed up hill under slight load.
Anyone got some suggestions? TIA
------------------
Best ET 14.413 @95.57 without
pulling valve covers or manifolds.
Also with stock 2.77 rear end!!!
One time I was in fourth going up hill about 60, and I noticed the TCC was pulling in and out, kind of like a surge condition. I know it didn't kick down to 3rd, since I manually shifted down and the rpm went up higher. I was giving it a little gas to maintain speed up the hill.
Amother time I was going around 50 up the hill and the TCC was also surging.
I have the TCC unlock prevent set at 60, and I lock/unlock the TCC in 4th at 50/45. Are these settings too high? I also noticed that GM had the difference between lock and unlock set at 2mph. This was consistent for many different bins. I don't think I hit the tables for unlock/lock for %TPS vs mph, since I didn't think I gave it enough throttle at those speeds. But I could be wrong since I didn't have my scan tool connected.
Today I scanned on the way to work, and no surge condtions were observed, so it seems to related to maintaining speed up hill under slight load.
Anyone got some suggestions? TIA
------------------
Best ET 14.413 @95.57 without
pulling valve covers or manifolds.
Also with stock 2.77 rear end!!!
TGO Supporter
Joined: Jul 1999
Posts: 10,907
Likes: 4
From: The Bone Yard
Car: Death Mobile
Engine: 666 c.i.
I had the same problem with "rolling hills". I found the TCC locking and unlocking, along with the EGR kicking in and out (you may not have noticed that one).
I found locking my TCC at a lower speed (45 MPH) along with controlling my EGR differently to prevent this "enable/disable" made highway cruising on "rolling hills" much smoother. Try keeping the TCC locked and EGR functioning.
I found locking my TCC at a lower speed (45 MPH) along with controlling my EGR differently to prevent this "enable/disable" made highway cruising on "rolling hills" much smoother. Try keeping the TCC locked and EGR functioning.
Thread Starter
Senior Member
Joined: Jul 1999
Posts: 786
Likes: 2
From: Guilford, NY
Car: 1988 IROC-Z
Engine: 350 TPI
Transmission: 700R4 w/TransGo
Axle/Gears: BW 9-bolt w/3.73s
That's kind of what I was planning on doing, just changing the TCC lock/unlock constants.
But what about that Unlock Prevent parameter? I understand it to be the value which the speed must drop below before the TCC can unlock. Hmmmm. So if I am set to 60, then below that the TCC can unlock? Guess I should lower that number.
I checked some recent scans, and I do believe the EGR is working. The duty cycle is flipping between 0 and 100%. I will most likely leave it alone for now.
But what about that Unlock Prevent parameter? I understand it to be the value which the speed must drop below before the TCC can unlock. Hmmmm. So if I am set to 60, then below that the TCC can unlock? Guess I should lower that number.
I checked some recent scans, and I do believe the EGR is working. The duty cycle is flipping between 0 and 100%. I will most likely leave it alone for now.
Supreme Member
Joined: Jun 2000
Posts: 7,554
Likes: 1
From: In reality
Car: An Ol Buick
Engine: Vsick
Transmission: Janis Tranny Yank Converter
<font face="Verdana, Arial" size="2">Originally posted by MikeT 88IROC350:
That's kind of what I was planning on doing, just changing the TCC lock/unlock constants.
But what about that Unlock Prevent parameter? I understand it to be the value which the speed must drop below before the TCC can unlock. Hmmmm. So if I am set to 60, then below that the TCC can unlock? Guess I should lower that number.
I checked some recent scans, and I do believe the EGR is working. The duty cycle is flipping between 0 and 100%. I will most likely leave it alone for now.</font>
That's kind of what I was planning on doing, just changing the TCC lock/unlock constants.
But what about that Unlock Prevent parameter? I understand it to be the value which the speed must drop below before the TCC can unlock. Hmmmm. So if I am set to 60, then below that the TCC can unlock? Guess I should lower that number.
I checked some recent scans, and I do believe the EGR is working. The duty cycle is flipping between 0 and 100%. I will most likely leave it alone for now.</font>
Supreme Member
Joined: Jun 2000
Posts: 7,554
Likes: 1
From: In reality
Car: An Ol Buick
Engine: Vsick
Transmission: Janis Tranny Yank Converter
<font face="Verdana, Arial" size="2">Originally posted by MikeT 88IROC350:
That's kind of what I was planning on doing, just changing the TCC lock/unlock constants.
But what about that Unlock Prevent parameter? I understand it to be the value which the speed must drop below before the TCC can unlock. Hmmmm. So if I am set to 60, then below that the TCC can unlock? Guess I should lower that number.
I checked some recent scans, and I do believe the EGR is working. The duty cycle is flipping between 0 and 100%. I will most likely leave it alone for now.</font>
That's kind of what I was planning on doing, just changing the TCC lock/unlock constants.
But what about that Unlock Prevent parameter? I understand it to be the value which the speed must drop below before the TCC can unlock. Hmmmm. So if I am set to 60, then below that the TCC can unlock? Guess I should lower that number.
I checked some recent scans, and I do believe the EGR is working. The duty cycle is flipping between 0 and 100%. I will most likely leave it alone for now.</font>
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