ek9 running dangerously lean.


T

tango'dcivic

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Aug 15, 2008
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hi lads, have yet another problem. Got car dyno'd recently and I was told it is running lean between 5500 6500 revs. He couldn't tell me why it was running lean so looking to find a reasons. I've put aem fuel rail and regulator on it but still not sure wat its like. What bout fuel pump, it'd be under more pressure around vtec so maybe fuel pump faulty? Or dirty fuel filter?
 
does it have a vtec controller on it? has someone lowered teh vtec without remapping teh fuel?
 
olly ek9 said:
does it have a vtec controller on it? has someone lowered teh vtec without remapping teh fuel?
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Ye i have the vafc2 but he tried putting more fuel in during the required rev but the ecu kept over riding the vafc and was of no benifit. Eventually the engine check light came on.
 
tango'dcivic said:
Ye i have the vafc2 but he tried putting more fuel in during the required rev but the ecu kept over riding the vafc and was of no benifit. Eventually the engine check light came on.
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The V-AFC cant adjust at full throttle. The AFC interrupts the MAP signal fooling the ecu into giving more or less fuel.
On Full throttle the VTEC system just gives max injector duration (max amount of fuel available).
Remove the pressure regulator and set VTEC back to OEM setting IMO.
On my old modded DC2 it started to run very lean when i removed the cat so be aware.
Good luck Dunx
 
Have you got intake, header and exhaust or similar ? this would cause it to run lean. Get management andhave it tuned on a dyno, problem solved! :nice:
 
EK9turbo said:
Have you got intake, header and exhaust or similar ? this would cause it to run lean. Get management andhave it tuned on a dyno, problem solved! :nice:
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I have mugen induction kit and 5zigen manifold and exhaust. I'm looking for apexi power fc.
Do ya no anyone selling one cheap?
 
type-r-dunk said:
The V-AFC cant adjust at full throttle. The AFC interrupts the MAP signal fooling the ecu into giving more or less fuel.
On Full throttle the VTEC system just gives max injector duration (max amount of fuel available).
Remove the pressure regulator and set VTEC back to OEM setting IMO.
On my old modded DC2 it started to run very lean when i removed the cat so be aware.
Good luck Dunx
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He disconnected the vafc because it wasnt doin anything. On the run after disconnecting it and was still running lean with vtec as standard and standard regulator. I'm confused
 
lambda sensor only affects normal driving not WOT

what did you set the fuel pressure at when you fitted the aem rail and regulator?
 
tango'dcivic said:
He disconnected the vafc because it wasnt doin anything. On the run after disconnecting it and was still running lean with vtec as standard and standard regulator. I'm confused
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As a temporary solution and to prevent damage - Reconnect the VAFC.

Use the AEM FPR to bump the fuel pressure then use the VAFC to trim/remove fuel where it is rich.

VAFC is bad at adding fuel, but it can take away. This is due to the sensor voltage on the MAP. If it sees too much (fuel signal) it will throw the code, if it sees too little, same deal with the code.

This is just another reason why the VAFC is not ideal for anything other than the mildest of modifications.
 
pimpinblackcivic said:
lambda sensor only affects normal driving not WOT

what did you set the fuel pressure at when you fitted the aem rail and regulator?
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I have it set to 1.25 bar without vacuum. I can't tell if its still running as lean as it was tho. I going to buy a power fc, hopefully it'll solve problem.
 
RagingAngel said:
As a temporary solution and to prevent damage - Reconnect the VAFC.

Use the AEM FPR to bump the fuel pressure then use the VAFC to trim/remove fuel where it is rich.

VAFC is bad at adding fuel, but it can take away. This is due to the sensor voltage on the MAP. If it sees too much (fuel signal) it will throw the code, if it sees too little, same deal with the code.

This is just another reason why the VAFC is not ideal for anything other than the mildest of modifications.
Click to expand...

That actually makes sense coz the engine light was comin on as he added more fuel. I am buying a power fc and selling vafc. Will this be a better solution?
 
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