Steve, do you have a decent scan tool? Maybe a little investigation will help shed light on exactly what's going on. Speculating about how this or that *should* work isn't very useful when what really matters is *how* things work.

So, some things I'd log with the scan tool... engine speed, spark, injector pulse width, both rear wheel speeds (I don't remember if there are accessible to the PCM), brake switch (% pressure would be better if there's a PID for that), traction control (indicates enabled or disabled), requested torque (EBTCM->PCM) and delivered torque (PCM->EBTCM). Might also include the APP % (requested) and TPS % (actual). I'm wondering if you're WSS signals are in fact close to one another as you roll into the throttle and how it's influenced by brake pressure. The independent variables you can vary are the amount of brake pressure, rate of roll on, and initial engine speed.

Thought question... What's the experience of folks with a line lock? Hmmm...

 

As I stated before I've had this problem as well and my car does have AH. When doing the burnout, it just stutters like the T/C was on. Cycling the AH/TC button has always solved it on the first try. Hence, my thought is that the car is seeing abuse mode on the tranny, I have not turned abuse off past what the predator tune did. I can turn it off with my HPTuners now. Also, I have never seen an indication in the DIC when this happens. Additionally, the pedel never buzzes like it does with the ABS and the car is clear cutting spark to kill power, which is clearly a TM or Abuse mode function. Maybe next time this happens I'll catch it on the scanner and we can see exactly what the car is doing. But I don't believe anything is broke, I think it's a tuning or T/C microcode problem, not a physcial issue. That said it's not all that bothersome for me, but I'd like to know what the issue is. As alway YMMV. Jeff

 

Of course, anything not there is clearly on the Internet.

 

 

Jeff,

This is exactly my experience as you describe it. I too have HPTuners. I'll take Topless Texan's advice and do some logging while it's doing this. I'm fairly certain it's strictly a "spark cutting" thing just as you believe.

 

I thought about this some more this afternoon and then went poking around with my scanner. Too humid to do that very long though. Damn few useful PIDs. Most of what I'm curious about is related to the EBTCM inputs. OTOH, if any of those inputs for any reason result in the torque reduction requests, you can notice that via the desired torque PID. Did see some nice clear statements in the service manual (one step up from the owner's manual) that the PCM and EBTCM both participate in TC. The PCM does it by pulling timing and closing the throttle while the EBTCM does it by applying rear brakes, bearing in mind the EBTCM also specifies the desired torque (nominally the max torque value in the PCM cal) based on it's own assessments of it's various inputs.

The braking actions of the EBTCM seem to be difficult to monitor, though I think you could do it with a Tech-II or the like. The PCM actions are much easier to monitor. The difficulty there might be the getting APP and TPS PIDs quickly since they're sort of second hand by way of the TAC. Better slow than none I guess.

Based on your description, I'm inclined to think you'll see PCM actions, but not triggered by the EBTCM's desired torque messages - I think that would light up the DIC. (You could probably test that theory by reducing the max torque parameter that everybody maxes out to a much smaller number.) If you don't see clamping due to EBTCM desired torque messages, you've eliminated a lot of possibilities.

If you see good agreement between the APP and TPS values that only leaves spark, which should be easy enough to see. Also, I did run across a TM/TC/Abuse throttle tip-in parameter I hadn't noticed before browsing around in EFILive's tuner earlier. I'll go back and peek at it again. I don't do much EFLive tuning on my '98 yet.

Still curious to hear what issues like this the line lock guys have or don't have.

 

Havn't heard of this before, can someone fill me in on this?
What triggers it? What happens? How do you turn it off/on?
Thanks,