Car running lean

OneQuikSix

Member
Joined
Jun 7, 2001
I posted this on Turbotweak.com but thought I'd share here too and let anyone else take a stab at my issues.

Please see the attached log. The car seems to run way lean no matter how much fuel I throw at it. The car is equipped with a Walbro 340 fuel pump less than 1000 miles old, hotwire kit, added ground leading from the fuel pump harness directly to the negative battery terminal, and a volt booster. Additionally, I am logging fuel pressure and it seems to be rising nicely with boost. It appears the fuel system is up to snuff.

I turned down the boost to the minimum my external gate will go and maxed out the fuel in settings 1 and 5 in an attempt to flood the engine. No matter what I do, the WBO2 and factory O2 sensors show lean. I even added some fuel to parameter 7 with no changes to the AFR. The closed loop feature in parameter 6 works like a charm though as the car drives great and idles at roughly 13.5 and cruises at 14.2 on the wideband.

I did change the turbo long ago from the TE-63 when I ordered this chip to a BB6262sp but I wouldn't think it flows that much more air at 8 psi than the old turbo. Plus, I made a few shakedown passes at the end of last season and everything appeared to be working fine then.

Until I figure out what is going on, I turned the alky off and lowered the timing in parameters 3 and 4 just to be safe. The attached file reflects those changes.

Thanks for your help.
 

Attachments

  • Aug 15 2013 c.dat
    348.4 KB · Views: 110
I may have found my problem. Check out this log from last season. This is a great side-by-side comparison because I had the boost turned down to the minimum for this shakedown pass. Even though I've added tons of fuel in the chip, and the injector duty cycle increased accordingly, the WBO2/factory O2 shows leaner than before at the same boost and fuel pressure levels. It looks like my fuel pump is not supplying adequate volume even though the pressure is rising. I'm going to double-check pressure with my analog gauge as soon as it stops raining. What do ya'll think?
 

Attachments

  • race 1.dat
    198.5 KB · Views: 47
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