WTF!! No one knows what's going on I took the car today to have it dyno tuned after ther LS6 intake and 237/242 603/609 install. Well, all is going well, I pay and all and me and a couple friends get in the car to drive home. Guy tells us to beat on it a bit to see how it does. So I pull out and go WOT, car goes to 4000'ish and shifts....then just bogs and stays around 4k. 15 different tunes later, it does the same thing.....finally, we put it back to stock tranny tune, I use my HPPIII and set it the way it was before I brought it in, still, the same thing, but only 95% of the time. Occasionally it ran like it was supposed to, which is like a monster. They have no idea wtf is going on, neither do I. Also, while there, the car started and idle'd perfect. No helping with the throttle or anything. Once I get it home, it won't start w/o cutting off, unless I stay on the throttle and work it until it idle's. If I shift it manually, it'll run the RPM's up like they're supposed to be, but if I just leave it in OD, it won't downshift but on rare occasions. Hell, usually it just stays and pulls in OD....why will it not downshift? Why will it work occasionally, and be stupid later? WTH is going on? Help! Someone! |
I fought with a very similar problem back when I was trying to be clever with the torque management on my car (trying to make a flat torque-limit profile). I would occasionally get into this "hang" state that I had to release throttle, to get out of. I never was able to eliminate it until I went back to the trans TM table and restored the stock values, & scaled. Though just zeroing it should work, if you like beating on your trans. I thought it might be abuse modes, killed them with no effect. Only the TM seemed to be involved in the end. My suspicion is that there is a nasty interplay between the trans torque model (Delivered Torque - Trans) and the torque management and/or abuse stuff (maybe hidden), that comes about from the very different torque vs slip RPM profile on an aftermarket converter. The PCM just doesn't know that you put on a piece where 2000RPM of slip at 4000RPM engine is normal; it refers to the built-in "mental model" of the stock converter and figures you must be making -huge- torque multiplication and wants to back you way off. There is a "Max KR vs RPM" field in HPTuners that your tuner may have an equivalent for, raise this from -10 (stupid) to something like +10 degrees and see if you move from hang to a slightly-detuned acceleration. That's where I've come around to, TM-wise; let it think it's in charge, but shorten its leash. HPP3 won't touch some of the things that your tuner might have done. Lot of stuff it just will leave the way it found it. However, new heads, big cam, not to say it couldn't just have a hell of a mystery rattle at 4000RPM and set off the knock sensors and pull out a whole mess of timing. That wants logging. So does the TM stuff, just different aspects. Now, the idle and shifting stuff I have no idea. Sounds like there's something fundamentally messed up, maybe TPS (shifting is TPS & MPH idle is TPS involved too) or something. I'd expect that cam to really whack out your idle and have a tough time learning, see cold start be really fat and hot start might be confused too; really low cranking VE and low idle VE relative to stock tables. Watch your commanded fuel air multiplier when you're having idle-death problems, your MAP and the IAC action. Raise the idle airflow to help backstop the RPM-control loop which can fall through the floor if things respond too slowly. Lower the open loop fuel air multiplier vs MAP vs ECT table in the areas that cover cold idle. Look at the VE table vs stock, see whether that has been massaged for you or neglected. Set the idle airflow floor to maybe 80% if the actual running idle airflow you log when it's doing good. For the 4000RPM hang, log the knock retard, the actual spark advance, the delivered torque-trans and see whether you are being hit by knock or by TM-at-shift. Go through the tables and see if there're any spikes or holes that you might get "stuck" on/in as you slide across the map, maybe just a fat-finger "oopsie" in some spark retard or fuel table. Try and narrow down the "suck space" and you'll narrow down the list of suspects.
Originally Posted by john3daly I took the car today to have it dyno tuned after ther LS6 intake and 237/242 603/609 install. Well, all is going well, I pay and all and me and a couple friends get in the car to drive home. Guy tells us to beat on it a bit to see how it does. So I pull out and go WOT, car goes to 4000'ish and shifts....then just bogs and stays around 4k. 15 different tunes later, it does the same thing.....finally, we put it back to stock tranny tune, I use my HPPIII and set it the way it was before I brought it in, still, the same thing, but only 95% of the time. Occasionally it ran like it was supposed to, which is like a monster. They have no idea wtf is going on, neither do I. Also, while there, the car started and idle'd perfect. No helping with the throttle or anything. Once I get it home, it won't start w/o cutting off, unless I stay on the throttle and work it until it idle's. If I shift it manually, it'll run the RPM's up like they're supposed to be, but if I just leave it in OD, it won't downshift but on rare occasions. Hell, usually it just stays and pulls in OD....why will it not downshift? Why will it work occasionally, and be stupid later? WTH is going on? Help! Someone! |
Thanks man! I'm going to have them check out this thread, hopefully it solves everything. |
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