Do I have a bad converter or ...
Do I have a bad converter or ... do I need some tuning adjustments? Between 1500-2500 RPMs I'm expeiencing a very hard hesitation/jerk. It happens in 2nd-4th gears and only after the engine has reached proper operating temps. I had a theory that it would happen after the engine warms because that's when the converter starts to lock up. To test this theory I plugged in another coolant temp sensor and let hang off to the side so the PCM wouldn't know when it reached operating temp. The problem went away, kind of. What I noticed was that the trans would still have an ever so slight jerk after the trans itself warmed up. All this started to happen three days after I installed a Yank TT3000, Dynatech LT headers w/ high flow cats, and FLP level IV 4L65E trans. I've checked the basics like fluid level, leaks, and any DTC's and have found nothing wrong. So my question is, is it more than likely a simple PCM adjustment or do I have a bad converter? What else can I do to check if I have a bad converter? Also, is there any other way to keep my converter from locking besides fooling my PCM into staying in open loop 'cause I know it's not healthy for my cats and engine? Thanks for any help.
TECH Senior Member
Joined: Nov 2001
Posts: 9,246
Likes: 3
From: Troy, AL
What you're feeling is the converter unlocking during the shifts and then relocking after the shifts. It's not noticable with the stock stall but it becomes more and more so the higher stall you go to.
If you have LS1Edit, disable lockup in 2nd gear and maybe 3rd too. 4th is really the only time you need lockup anyway. But, if you really want to keep lockup in 3rd, program it to only lockup under light throttle conditions. Say, under 15-20%. This way, during normal acceleration, the converter will stay unlocked until you get into 4th. But, it will leave the option of having the converter locked around town with the gear selector in 3rd. This is how I have mine programmed and I really like it.
If you have LS1Edit, disable lockup in 2nd gear and maybe 3rd too. 4th is really the only time you need lockup anyway. But, if you really want to keep lockup in 3rd, program it to only lockup under light throttle conditions. Say, under 15-20%. This way, during normal acceleration, the converter will stay unlocked until you get into 4th. But, it will leave the option of having the converter locked around town with the gear selector in 3rd. This is how I have mine programmed and I really like it.
Originally Posted by Colonel
BTW, you really don't want to be running around in open loop all the time. Your plugs will foul sooner, your cats will croke, and your MPG will be 
