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ECU ignoring Commanded Rail Pressure from tune

DallasDub94

DallasDub94

Go Kart Newbie
Black_gti_blaze said:
its so strange, yesterday at freeway speeds the car was pulling great! in 5th-6th gear easing into full throttle trims only get to 1.08 or so and car hits requested AFR and car pulls great!

Its these low speed and low rpms situations where the car doesn't want to react fast enough, studders and doesn't pull as hard with trims going to 1.25 :(
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My problem is almost always when doing single 3rd or 4th gear pulls from low rpm (~2k) for logs. Wide open on the highway going through multiple gears rarely causes a problem.
 
OhioMK6

OhioMK6

Ready to race!
Stock-GTI said:
My problem is almost always when doing single 3rd or 4th gear pulls from low rpm (~2k) for logs. Wide open on the highway going through multiple gears rarely causes a problem.
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Same exact situation for my issue as well. Basically the exact type of pull that a tuner requests for datalogs :laugh:
 
93serprise

93serprise

Ready to race!
OhioMK6 said:
Same exact situation for my issue as well. Basically the exact type of pull that a tuner requests for datalogs :laugh:
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Yep, same exact scenario for me as well. Still waiting on my Vagcom to be delivered and then I am logging stuff on my Unitronic tune. Haven't received my 3rd tune revision yet from Stratified.
 
OhioMK6

OhioMK6

Ready to race!
93serprise said:
Yep, same exact scenario for me as well. Still waiting on my Vagcom to be delivered and then I am logging stuff on my Unitronic tune. Haven't received my 3rd tune revision yet from Stratified.
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Excited to see the Unitronic logs! If your fuel pressure is perfect on the Unitronic, tune there's clearly a COBB software issue that needs to be addressed.
 
J

Jiffyjetta

Ready to race!
MmmmmBoost said:
The black grill infront of the maf ? It doesn't really straighten anything, more or less just to block big things going into it.
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Yes it does actually straighten the air. Nearly every single maf on every car has a air straightener.
When air travels through the air box, filter, and tube, it becomes turbulent. Every computer is tuned for a specific maf, with a specific amount of turbulence.
Some cars are more sensitive than others. For example, Subarus are notorious for running very poorly with any mods to the intake or maf without a tune.
I personally lost power when I installed an intake on my TSI. I checked fuel trims and I was at 15-20 long term. I installed an air straightener and fuel trims went to 3-5 and power was restored.
 
M

MmmmmBoost

Ready to race!
Jiffyjetta said:
Yes it does actually straighten the air. Nearly every single maf on every car has a air straightener.
When air travels through the air box, filter, and tube, it becomes turbulent. Every computer is tuned for a specific maf, with a specific amount of turbulence.
Some cars are more sensitive than others. For example, Subarus are notorious for running very poorly with any mods to the intake or maf without a tune.
I personally lost power when I installed an intake on my TSI. I checked fuel trims and I was at 15-20 long term. I installed an air straightener and fuel trims went to 3-5 and power was restored.
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May be adequate for the stock intake but I know a bunch of guys that kept having maf issues with the stock maf housing and aftermarket intakes and a proper straightener fixed it for them. Guess I'll find out soon enough.
 
J

Jiffyjetta

Ready to race!
MmmmmBoost said:
May be adequate for the stock intake but I know a bunch of guys that kept having maf issues with the stock maf housing and aftermarket intakes and a proper straightener fixed it for them. Guess I'll find out soon enough.
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Sorry I misunderstood your previous statement. I thought you were saying that the maf straightener does not serve a purpose in general. I do agree that a better quality maf straightener could help improve.
 
M

MmmmmBoost

Ready to race!
Jiffyjetta said:
Sorry I misunderstood your previous statement. I thought you were saying that the maf straightener does not serve a purpose in general. I do agree that a better quality maf straightener could help improve.
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All good, I figured the grate they put infront of the maf was to help a bit but it's so open in size that I doubt it does much. Hopefully the new one will do something.
 
Black_gti_blaze

Black_gti_blaze

New member
MmmmmBoost said:
All good, I figured the grate they put infront of the maf was to help a bit but it's so open in size that I doubt it does much. Hopefully the new one will do something.
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Which air straightener did you get? I’m willing to try this too but the ones I saw are expensive as shit with shipping!
 
J

Jiffyjetta

Ready to race!
If your looking to keep it cheap, try going to your local junk yard and looking at gm cars with mafs. They usually have pretty large mafs and the air straighteners are removable with a screw driver. Buick, Pontiac and Chevy's from the mid 90s to 2000s should all have them. Some of the mafs are built into the throttle body so the straightener is in the there right before the throttle plate.
 
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