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Hesitation between 2000 - 3000 RPM

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I have a problem of hesitation between 2000 - 3000 RPM after TGV delete.

Here is a log with the problem: https://datazap.me/u/welaish/stumble2k-3k

My question is why it happened after TGV deletes, I have updated all the tables to the non-Cruise one. but still I cannot fix it and AFR is spot on and no vacuum leaks.

Do I need to change the injector timing? or what would be the problem?

I haven't personally seen this issue as the JDM vehicles I primarily deal with don't use the TGV system. What you're reporting however is a common complaint that seems to come down to the AVCS mapping. I'd focus your efforts on these tables and see if you can eliminate the issue by optimising the overlap in the 2000-3000 rpm part throttle area.

Thanks Andre. I will try to improve that see. did you spot anything on the Logs for the AVCS?

I reduced the intake timing advance in this area from ~15-20 to 10 degrees and its better but its still there.

Do I reduce it to 5 or 0? and what do i do with the exhaust timing.

did you cover the AVCS part in any of you courses? thanks in advance.

ur log is only upto 2500 rpm

GRB STi (except JDM) have stumble issues from 2800 RPM to 3000 its a very known issue

usually when upgrading to stage2 you feel it more than in stock

but when you change the injectors to anything bigger you will def feel it

there are a lot of ways to fix

i recommend changing the FPR to pre 08 STI and changing the vacuum source for the FPR

here's how to do it


also you will need to edit one of the maf compensation tables, i forgot what it was called (i think load maf compensation)

cobb did a lot of testing on this


good luck

Thanks RasheedNash.

Negative. this is not the Stumble, I have FPR and different Vacuum Reference and Fuel rails as well. it happened after the TGV deletes only.

The Stumble symptoms are not there, with the stumble you will find the AF Correction are deviating to positive correction when you drive on that RPM. which is not happening in my case.

Post ur avcs maps

Try to lower the exhaust angles in that area

I never had this issue when only doing the tgv deletes

Here you go: attached.

this is after I lowered the Intake Cam to 10 Degrees.

Attached Files

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