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Lean spike/ stumble at highway speed

 
Old Jan 9, 2019, 04:00 PM
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Lean spike/ stumble at highway speed

OHello all,
I got a few things installed over a month ago. Gtx3076r, Id1050x, DW65 fuel pump. After having a few issues I went to a tuner who was able to fix all of them.
Long story short, I have an issue that I canít seem to fix. When Iím cruising at highway speeds (60-80mph) I get a stumble/studder and a lean spike. It only happens at partial throttle. (Like when trying to maintain speed. At WOT and idle itís near perfect. The tuner said it was a mechanical issue, I think itís in the tune. Please give me your input.
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Old Jan 10, 2019, 02:59 PM
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I had something similar at partial throttle where it would lean out and stumble between 3-4k rpm. I'm flex fuel tuned. My tuner found a tweak he needed to make in the tune when I had run really good quality of E85 (~e81). At e70 and below I had no issues.
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Old Jan 11, 2019, 07:12 AM
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Originally Posted by AJV View Post
I had something similar at partial throttle where it would lean out and stumble between 3-4k rpm. I'm flex fuel tuned. My tuner found a tweak he needed to make in the tune when I had run really good quality of E85 (~e81). At e70 and below I had no issues.
do you know what the tweek was?

Thank you
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Old Jan 11, 2019, 12:01 PM
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Originally Posted by wizechef View Post


do you know what the tweek was?

Thank you
It was a bit of a fuel adjustment. Can't say exactly what was changed.
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Old Jan 11, 2019, 03:31 PM
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Originally Posted by AJV View Post
It was a bit of a fuel adjustment. Can't say exactly what was changed.
thank you.
Do you remember how he found the issue?
This Monday, Iím literally having the tuner sit in the car with his lab top plugged in while I simulate the issue. Hopefully he finds it then, cause he says everything looks good.
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Old Jan 12, 2019, 11:57 AM
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Do you have OEM fuel rail or aftermarket?

Also look into making sure MAF/MAP tables are tuned correctly and if so, then look into the injector linearization PW adder table, you have to tune that properly as you start using larger and larger injectors.

https://www.evolutionm.net/forums/ec...ion-table.html
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Old Jan 23, 2019, 06:08 PM
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Originally Posted by razorlab View Post
Do you have OEM fuel rail or aftermarket?

Also look into making sure MAF/MAP tables are tuned correctly and if so, then look into the injector linearization PW adder table, you have to tune that properly as you start using larger and larger injectors.

https://www.evolutionm.net/forums/ec...ion-table.html
itís a stock fuel rail. Iím almost positive itís the tune. I will try a different tuner cause this one is saying itís Machanical. I checked the plugs, they were all clean. and did a compression test that ranged from 142-151. I also did a boost leak test. Found a few leaks that were fixed and the issue was still there.

If itís not the tune it might be the fuel pump? Iím lost at this point
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