i installed a walbro intank pump in my car a while back and ever since then I have been having tuning issues. Besides the occasional stumble between shifts the car leans out a lot on the big end. The a/f stays between 11-12 all the way through the power band until about 5500 and then it works its way up to 14 by 6400. Anybody ever experience this or know what is wrong?

BTW, the car is a '00 SS with MMS S2x heads/cam. The car is making about 430 despite this problem.

 

Top off your tank and try running again...I mean full! The walbros are finicky about half full or quarter full tanks. I run mine completely full just to be sure...yeah it sucks but it will have to hold me over until I can get a real fuel system.
Anyone have a fix for this problem? Ive heard of many cars having this problem...especially Fbods and Turbo buicks.

 

Ive never had a problem with this <img src="images/icons/confused.gif" border="0"> even with my 200 shot of N2O. I dunno <img src="images/icons/confused.gif" border="0">

 

I had that prob as well. It took 2 things to fix it...10gauge wire from front of car to the tank and a good fuel pressure regulator. What size injectors do you have and does your car hold fuelpressure thru a run?

 

currently running stock injectors. The problem started with the installation of the pump. Before it would hold the same a/f all the way through the range