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? :crycry:



Thanks for reading/helping out!

I do/did had only 2-3 bars left on the fuel gauge... Could that had anything to do with it?

Just filled her up, same problem :(..

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.

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.

Nah, the temps might dropped a bit, not more than 10 degrees celcius.... Im clueless about this one :(

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... :confused:

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.... :suspect:

Temperature has slightly dropped with about 10-20 Fahrenheit so that should not be an issue right?

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?

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!