Throttle pulling back at 5700 rpm

[bryontro]

I'm very new to logging so apologies in advance. Ran my first log today on a whipple tune stage 2 auto. I noticed things are flatter up top than normal. So using VCM Scanner/RTD I did a 4th gear WOT pull. Sure as crap, about 5700 rpm the ecu pulls throttle away and settles at 50% while I am pinned to the floor mat. Boost pressure drops to around 6 psi. Knock retard is -3.8 degrees on the log at the point throttle backs off and steady. Timing advance is 17 degrees. If I read correctly that means the ECU is adding timing. Using 93 shell this is a pump gas car. I sent the log to whipple to see what they say. The ECU doesn't like something, I'm just not smart enough yet to find the reason in the data yet. Feedback is welcome. Thanks.

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[engineermike]

Throttle closure is always fun to diagnose. Probably a dozen things can cause it. Lspi load limit, insufficient fuel capacity, tc/at, and many more can cause it. Whipple has tried some goofy things like cold ect throttle limit that didn’t work the way it was supposed to. You can log driver torque demand, engine brake torque, driver demand limit, torque source, airlimit source, engine max torque source, etc. and sometimes they will point you in the right direction.

 

[Brandon91]

Are you turning traction control off? My car will drop timing from 22 to 13 degrees with TC on and close the throttle to 72 from 85.

 

[Cory S]

Did you have AdvanceTrac off?

 

[bryontro]

Yes, advance track was off. Whipple reviewed the tune and confirmed, throttle is backing off for some reason not related to fuel, knock, timing, etc. It appears to be a tune related issue. I still have the tomahawk and the original tune from my install last winter. I may try that and see what happens while they work through it. They are looking into it.

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