Ok, for some reason over the last couple days, my truck has been running like crap. It feels like it's gonna stall or something when i'm in 4th and the tcc locks. I don't know what the hell is going on. Is there a way to diagnose the problem using hptuners? For now i'm just gonna raise the mph that the tcc locks at. The only thing i've changed is i added a ported throttle body. i'm told that can mess with the trans shifts somehow.
02 GMC Sierra 2500HD CC 4X4 6.0L LME 408 w/ET245, Kenne Bell 2.8L, Yank SC3000
TCC will unlock when you have misfires, you might see
the SES light blink. Could be it's pulling timing for KR.
That's where I'd start, logging the spark related stuff
including burst knock, along with the "usual suspects"
(RPM, MAP, TPS%, at least one of the front O2s, try and
put a box around it and move the box in the direction of
what looks most wrong, based on what you find (drop
PIDs that turn out to be irrelevant and add ones that
are new suspicions). Being a little lean and upshifting
at boost is a likely way to make some stumbling. Your
shift-to RPM may be low enough to bump you back into
the speed density tune momentarily. If you get about a
second of stumbling and then it takes off then that
indicates you are stepping into a hole and it takes either
re-closing the loop or returning to MAF-based airflow
metering to get you right.
Look for a "lean hole" in the O2 readings 1-2 frames
before the stumble, KR at the stumble.
Look for a misfire spike in the current misfires 1-8 that
might indicate a weak cylinder spark-wise that doesn't
like high cylinder pressure; plug gap, plug wires, etc.
Ported TB "shouldn't" affect anything about mixture,
not like a ported MAF. Especially if this truck is like others
I've seen and has the MAF a foot and a half away from
the blade. But install oopses do happen and you might
want to recheck for a vacuum leak around there.
i am totally confused. would you be willing to tell me exactly what to log and let me send it to you to look at? i've tried asking Allen Nelson and i get nowhere. yes, i do have a nelson tune also. I definately do see lots of KR lately. Don't know why, i'm only running 17deg at wot. i'm totally confused. Also, I can't get my boost gauge to read anything over 8. i was seeing up to 11lbs boost until i put the tb on. what the hell. i thought i had a bad plug or wire but i just changed them both on sunday and it made no difference.
02 GMC Sierra 2500HD CC 4X4 6.0L LME 408 w/ET245, Kenne Bell 2.8L, Yank SC3000
17 degrees on a non-intercooled is more than too high. Probably why you're seeing a lot of KR. Missfires don't cause transmission slippage, but removing the TQM on the trans side is slow transmission death. Tried to make that plain to NP several times. Check your MAF sensor next...belt slippage (boost losses) after that. Your TBI unit could be leaking...this'll throw off the boost numbers, and mess up the airflow that the MAF is seeing.Originally Posted by DanaliHD
Lyndon.
Misfires unlock the converter which will -feel- like
slippage.
One thing to do is to log the trans input and output
shaft speeds along with TCC slip. Look at the shaft
speed ratio during the slip event. In proper operation
the ratio should be a constant while in gear and all
slip should be across the converter. If you see the
input/output ratio "flare" then you have a holding
problem in the trans. If you see nothing like this but
a big slip in the converter, then that's good. At least,
it's not guts.
A truck with boost should easily walk right past the
TCC's holding torque especially at low TPS. I was
getting > 500RPM converter slip on hills with my TCI
converter, and setting codes. Once the slip code sets
the trans won't even try to lock up.
I called whipple today and they claim that my boost problem is due to an exhaust problem. Steve says i probably melted my cats and shot a piece of it into my muffler causing a backpressure/blockage problem. does that make sense?
02 GMC Sierra 2500HD CC 4X4 6.0L LME 408 w/ET245, Kenne Bell 2.8L, Yank SC3000
Absolutely. It's a possibility your converters are restricted. Relatively simple to check by testing exhaust backpressure (pre-cat).
If missfires are keeping the converter unlocked, you should have a trouble code which states such. P0300 (Random) or P0301-P0308 (Specific cylinder).
Lyndon
www.ecmprogrammer.com
How do i check my exhaust backpressure? I did a log today for misfires and i had none. I am heading to the exhaust shop tomorrow i think so they can take a look at it. I hope it's an easy fix. I'm now only running 11deg timing at wot and still seeing KR. wtf? i'm actually seing the KR at only 60% throttle. Im thinking it's false knock. anyway, i'm still only seeing 7lbs or so on my boost gauge and that's a problem.
02 GMC Sierra 2500HD CC 4X4 6.0L LME 408 w/ET245, Kenne Bell 2.8L, Yank SC3000
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