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Strange A/F reading

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Old 07-23-2011, 02:00 PM
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Default Strange A/F reading

Hey guys,

i'm running a Greddy turbokit at 6 psi at the moment, got a 3"headerback with HFC, emanage ultimate and i'm using an AEM UEGO wideband.

Since i got her tuned i had an A/F that dropped to 12.4 when going into boost and that drops to 11.5 when i keep her in boost.. ( sometimes it fluctuates between 12.4 and 11.1 depending on gear/rpm..

But since today, ( i have not changed anything ) the A/F drops to 12.x when going into boost, and then it raises up to 13.5 when im holding the throttle under WOT. ofcourse i let off the gas immediatly at that point to prevent damage.

I tried several gears, and several RPM's to see what the A/F does and it's the same sequence.. first 12.5, and then it raises to 13.X...

What COULD be the problem causing my A/F to suddenly behave like this out of the blue?



Thanks for reading/helping out!
Old 07-24-2011, 02:37 AM
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I do/did had only 2-3 bars left on the fuel gauge... Could that had anything to do with it?
Old 07-24-2011, 04:18 AM
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Just filled her up, same problem ..
Old 07-24-2011, 12:14 PM
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What was the A/F raatio at when it was tuned? Has the temperature changed drastically on those days that it was acting different. Atleast its richening up and not leaning out.
Old 07-24-2011, 01:05 PM
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It is leaning out he said that it now goes to 13.XX where as before it was 11.XX

Has the temperature changed a lot since it was tuned? I know that it is pretty hot all over the U.S. right now.
Old 07-24-2011, 01:29 PM
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Nah, the temps might dropped a bit, not more than 10 degrees celcius.... Im clueless about this one
Old 07-26-2011, 02:34 AM
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I checked for a loose wideband bung, it's stil okay, i've reset the ECU, checked vacuum hoses but it's all looking great...

I don't think it's possible that the Emanage Ultimate changes its fuel maps after a while? The Oem ecu might relearn some partial throttle settings but going WOT would always be the same i guess....

Temperature has slightly dropped with about 10-20 Fahrenheit so that should not be an issue right?
Old 07-26-2011, 03:28 AM
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It is possible you have a fuel restriction or your pump is going bad. You also need to check the vacuum line going to your fuel pressure regulator. You will lean out quite a bit if this comes off. Personally I would ditch the Emanage for something better though.
Old 07-26-2011, 04:37 AM
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Originally Posted by sohc_mshue
It is possible you have a fuel restriction or your pump is going bad. You also need to check the vacuum line going to your fuel pressure regulator. You will lean out quite a bit if this comes off. Personally I would ditch the Emanage for something better though.
Well, i got a walbro 255LPH, it has run about 10K miles... Could it go downhill so fast?
Old 07-26-2011, 10:47 AM
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I do THINK that the walbro "sounds" different than when i installed it. It makes a pretty loud buzzing sound when the car is idling.

I think i better replace it with a HRC fuel pump, which i heared good things about and it should be alot quieter then a walbro and there isnt a broken one thats reported so far..

A bad performing current walbro could be my issue right here but im not sure...

Thanks for the help so far!


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