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JZ motors in everything!
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Discussion Starter #1
I can't seem to tune this out, not matter how much I increase VE.

With the same load and boost on the dyno it runs rich in these areas. Something about the boost pressure quickly rising cause this. It's worse between shifts as you can see, but even starting at a low RPM street pull it's leaning out too much.

This is with o2 sensor correction off. I've tried with Accel fuel off and not seen a change. I can increase the VE way high and it leans out, then goes pig rich!

I've replaced the AEM 5 Bar map sensor with no change

750cc injectors with good fuel pressure

Suggestions?

 

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162 Posts
From that log it looks like you are going lean after changing gears, you need to tune your accel fueling. Log delta TPS and mass air flow to see where you need to tune.
 

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Question to suit.
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3,562 Posts
Acceleration enrichment.
 

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So does it do this when you hit it from 2000rpm and run through that single gear or is it only gear changes?
 

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JZ motors in everything!
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573 Posts
Discussion Starter #5 (Edited)
After doing more street tuning I've got this issue mostly sorted, but the fuel map sure looks weird!

Yes it was doing this even on a pull from low RPM

I ended up adding tons of "fuel" (VE) through ranges and it's mostly cured. But why the VE has to be so high through certain ranges is a little weird to me. (map needs smoothing yes)



Just seems weird that the VE would need to be way higher at 14 psi than 20...

And I tuned the fuel map on the dyno at these load ranges (steady state hold on a dynapack) and had it dialed. However, holding it at 14psi on the dyno at 4500 rpms for example didn't take full throttle.... maybe that's were the difference is. VE through these ranges was about 1.05-1.08 on the dyno
 

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Yeah. You have some serious issues with that ve map. Something may not be setup right. Don't steady state tune boost. There is no reason to. You need to tune boost sweeping at full throttle. Meaning run through the gear like you would on the street. You are never going to hold it at 14psi at 4500rpm.
 

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JZ motors in everything!
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573 Posts
Discussion Starter #8
How much lag can we estimate from the wideband reading? After studying the logs it looks like it might be about .1 seconds. My sensor is about 4 inches from the turbo outlet
 

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JZ motors in everything!
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573 Posts
Discussion Starter #9
Yeah. You have some serious issues with that ve map. Something may not be setup right. Don't steady state tune boost. There is no reason to. You need to tune boost sweeping at full throttle. Meaning run through the gear like you would on the street. You are never going to hold it at 14psi at 4500rpm.
I'm not sure what that could be. I'd be happy to send you the xcal if you want to take a look.... :(
 
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