Throttle response to pedal problem in 4th gear. Scan inside.

[jatolbert]

Ladies and Gents,

I have a twin turbo Z06 with a fully built engine. I recently got the car all together and have been driving it a bit for the past month or two. Well, Sunday was the first time that I have run the car really hard as I was at a roll race. The car is still on very low boost but did make decent power. However, one problem:

On a few occasions, not all, I lost the throttle in 4th gear. As you will see from the scan, the throttle works fine in 2nd (launch gear) and 3rd gear, but in 4th, despite the accelerator position at WOT (85%), the throttle was only at 40%. It seems to be a computer/tune issue, not hardware issue since the commanded throttle is 38%. 4th gear WOT is from roughly the 39 second mark to roughly the 40.5 second mark. So far, it seems as though it has only happened in 4th gear but it may possibly have happened in other gears when I was not scanning.

Any help, thoughts, suggestions would be appreciated.

Josh

[schpenxel]

Post tune.

[jatolbert]

Attached.

[schpenxel]

I got nothin on that one

[jatolbert]

That sucks. But thanks for looking.

[GHuggins]

Apply the tcs patches and see what that does in the OS section - didn't see anything else in the tune right off the bat otherwise...

[jatolbert]

Ill give that a try. What exactly do these patches do? Do I need TCS patch 1, patch 2 or both? I actually have the TCS disabled. Would this patch still potentially affect me?

[GHuggins]

I can't honestly say ye or ne on that I always apply the patches when doing sd tunes - this was the main reason why they were added - to make the traction control work correctly - but if it's disabled, I'm not sure?

Sorry can't be of more help - other than throttle being commanded to close, do you notice anything else?

[jatolbert]

Thanks for the feedback.

Didn't really notice anything else other than the associated sudden loss of power. Also, according to the scan, the car went pretty lean after the loss of throttle but I think this is due to the VE at the low MAP and the fact that DFCO may have kicked in. I wish their were more items showing some sort of explanation but I do not see them right now.

[ke5gnz]

I am having the same problem throttle only opening 38% I posted this a while back and still to this day have the same issue, with TM disabled or enabled. I believe it has something to do with the tac parameters, as I changed mine a small amount in the area that this was occurring and the problem went away but then would go into rep with ecm failure code. changed tac back to stock and the 38% came back but no more rep. I did find that if I rolled into the throttle in the problem area it would go to the 89%, don't know if this helps or not as I still have the issue.

[jatolbert]

That's very interesting that you've had the same problem. What mods do you have on the car? Have you ever gotten throttle related dtc codes (P2138 or similar)?

[GHuggins]

What happens if you set all throttle codes to disabled? This of course without messing with the tac.... Wondering if this is something in the background screwing with a particular OS?

[GHuggins]

Just watched the log for the first time - sorry should have done that to begin with - your not only cutting throttle, your cutting fuel and at a specific speed from the looks of it... What happens if you change your speed limiter settings?

[ke5gnz]

{That's very interesting that you've had the same problem. What mods do you have on the car? Have you ever gotten throttle related dtc codes (P2138 or similar)? }



I have had the P1516 code and the P0606 codes. The current setup is a 2010 Silverado with an ls2 with ls3 heads, lsa cam, slp fab intake, twin 64/66 Garrett gt3582p turbos, NW 102 TB, ls7 injectors, and meth injection. this is my daily driver.

[jatolbert]

GHuggins: that may be a good thought. I wouldn't think that would be an issue, but who knows??

Ke5gnz: I've never had either of those codes. The one thing that jumps out that we have in common is the NW 102 TB. There maybe something with the TB that's the problem.

[ke5gnz]

jatolbert ( I've never had either of those codes. The one thing that jumps out that we have in common is the NW 102 TB. There maybe something with the TB that's the problem. )


That could be but I would think that more people would be having this issue with as many NW 102's that are being utilized. I think it is something with the amount of airflow at a set RPM, Gear, Speed, and a portion of the ECM we cant change in the TAC settings. My ecm is the E38 and the TAC is VSS referenced. I might be totally off base here but with me being able to bring the throttle up slowly and acquire the 89%, yet if I nail it then I get the 38% and stay there until I let off. Have you tried to roll into the throttle when shifting to 4th vs nailing it. (Racing, who thinks wait I have to roll into the throttle)

[jatolbert]

jatolbert ( I've never had either of those codes. The one thing that jumps out that we have in common is the NW 102 TB. There maybe something with the TB that's the problem. )


That could be but I would think that more people would be having this issue with as many NW 102's that are being utilized. I think it is something with the amount of airflow at a set RPM, Gear, Speed, and a portion of the ECM we cant change in the TAC settings. My ecm is the E38 and the TAC is VSS referenced. I might be totally off base here but with me being able to bring the throttle up slowly and acquire the 89%, yet if I nail it then I get the 38% and stay there until I let off. Have you tried to roll into the throttle when shifting to 4th vs nailing it. (Racing, who thinks wait I have to roll into the throttle)

I agree. I didn't necessarily mean a hardware problem, but a tuning issue when using the TB.

No, I have not really rolled into the throttle. Like you said, you have to make yourself do it while racing.

[jatolbert]

Oh, what are your ETC scalars and stuff in the idle>airflow section? Also, are your throttle maps still stock? Will you post your tune so I can compare and see if I can find potential issues?

I'm an E38 and I think I'm rpm referenced.

[Aaron407]

I'm not sure if powerhop TM is governed under the master TCS switches, but it might be worth turning off those settings in your tune as they're still shown as enabled. I can see your speed jump a lot at your shift (about 12 MPH over 0.1 seconds), then come back down, which makes me think it's torque management of some kind and possibly powerhop.

Maybe log the different torque management type PIDs, as well as delivered torque to see what's going on.

ETC Torque Management Type
Spark Torque Management Type
Fuel Cut Torque Management Type

[ke5gnz]

jatolbert (Will you post your tune so I can compare and see if I can find potential issues)

I will post a tune this afternoon