Quote:
Originally Posted by solowma
Next and the most pressing issue. When we let off the throttle at any position or rpm, the AFR goes extremely rich and then backs off and goes stoich. How do I stop this or make it more bareable?
The issue is, we believe with all this WOT then off it has fauled the plugs and that is understandable. They are being changed on the weekend and we will try again. The truck will run great the first WOT run and then studder and hesitate on any of the runs after that. Plugs probably are the problem but if you drive a little more to clear out the fuel and then step on it again and same thing happens. Any help will be greatly appreciated.
Long post I know. I can provide JET program and data longs if needed.
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Are you still using the MAF sensor and if so, where do you have the MAF sensor located? If you have it far from the throttle body, what can be happening when you let off the throttle while under boost is all the pressure that builds up at the closed throttle bounces back out of the induction system past the MAF sensor which will register as airflow. I had this problem when I put a turbo on a 3800 years ago. The MAF sensor was mounted between the air filter and turbo inlet and it did the same thing yours is doing when I let off the throttle from a hard run. The fix was to mount the MAF sensor just before the throttle body (in the induction system between the throttle body and intercooler). Doing this fixed all fueling issues and also increased throttle response and the quality of drivability. Your Denali's stock MAF sensor should be good to about 400+ crank HP w/ boost; but keep tabs on its output frequency at full boost. If it is getting close to 11,500 hz or more, you are probably "outflowing" it and should get a bigger MAF.