Converter unlocking/locking as I crusie down the highway
#1
11 Second Club
Thread Starter
Join Date: Feb 2002
Location: Norcal
Posts: 639
Likes: 0
Received 0 Likes
on
0 Posts
Converter unlocking/locking as I crusie down the highway
I have a 2000 SS that has a built tranny and 4000 stall converter in it and recently, I've noticed as I was drivng down the freeway the converter starts unlocking for a bit, then locking. This all happens on flat roads and no load on the engine. The engine has has the usual intake mods and an underdrive pulley and has been dyno tuned. The only change I've made recently has been the additon of 3.73 gears via a 12 bolt swap. I've had the issue one time before and I took it back to the tuner and it was fixed for a while. I don't recall if it happened before or after the rear end swap though.
When I get time, I will take it back and have the tuner look at it, but until then, anyone have any ideas?
When I get time, I will take it back and have the tuner look at it, but until then, anyone have any ideas?
#2
TECH Senior Member
iTrader: (96)
Join Date: Aug 2007
Location: Turnin' Wrenches Infractions: 005
Posts: 24,240
Likes: 0
Received 81 Likes
on
72 Posts
I had this happen years back on a 700r4. It was due to a broken temp sensor. Programming did not allow converter lock-up until coolant reaches a certain temp. By the sensor being faulty, it was throwing the computer for a loop and was causing random locks and unlocks around 45 mph. BTW, the temp gauge in the vehicle was still working at the time, so perhaps there were 2 different ones. On the SS, I have noticed light throttle lock-up happen precisely at 113 degrees as i'm leaving the house. This is on an aftermarket temp gauge in the coolant bypass line. It apparently restricts lock-up below that temp just like the old 80s model 700R4 did. Funny how in 15 years things dont change much.
#3
11 Second Club
Thread Starter
Join Date: Feb 2002
Location: Norcal
Posts: 639
Likes: 0
Received 0 Likes
on
0 Posts
I had this happen years back on a 700r4. It was due to a broken temp sensor. Programming did not allow converter lock-up until coolant reaches a certain temp. By the sensor being faulty, it was throwing the computer for a loop and was causing random locks and unlocks around 45 mph. BTW, the temp gauge in the vehicle was still working at the time, so perhaps there were 2 different ones. On the SS, I have noticed light throttle lock-up happen precisely at 113 degrees as i'm leaving the house. This is on an aftermarket temp gauge in the coolant bypass line. It apparently restricts lock-up below that temp just like the old 80s model 700R4 did. Funny how in 15 years things dont change much.
I have an aftermarket water temp gage to go along with the dash one and I have noticed that the dash gage can be freaking out sometimes while the pillar gage is reading normal. Come to think of it, I think the unlock/lock issue started after my overheating issues started. I may not have noticed it because I don't drive it to work anymore except for the other day when I noticed the problem.
Anything else?
#4
TECH Senior Member
iTrader: (96)
Join Date: Aug 2007
Location: Turnin' Wrenches Infractions: 005
Posts: 24,240
Likes: 0
Received 81 Likes
on
72 Posts
IMO, overheating in traffic but not on the highway indicates airflow issue. Motors need airflow whether by wind on the hwy or artificially by the fans. Stop and go overheating points to fan issues to me. Could be a relay or a fan motor. Both are cheap and relatively easy fixes.
#6
11 Second Club
Thread Starter
Join Date: Feb 2002
Location: Norcal
Posts: 639
Likes: 0
Received 0 Likes
on
0 Posts
Hmm, I can hear the fans come on when the car is at idle....I wonder if it's my 166,000 mile radiator, it could have clogged arteries, lol. I also have two tranny coolers w/ fans mounted in front of the radiator, I'm sure that is a contributing factor. The overheating problem started last summer when my EWP went out and I put a stock water pump back on.
#7
Trending Topics
#10
12 Second Club
Join Date: Jul 2006
Location: NW Ohio
Posts: 138
Likes: 0
Received 0 Likes
on
0 Posts
I've also heard about this happening when the engine detects misfire.
Since aftermarket converters are smaller than stock converters, the engine detects misfire and unlocks the converter.
Don't know if this is the problem in your case though.
Since aftermarket converters are smaller than stock converters, the engine detects misfire and unlocks the converter.
Don't know if this is the problem in your case though.