lean at wot snap in gear

[mecnic99]

This is a 5.3 with a asa 525 cam. the issue is a constant lean condition under a wot snap from idle. I have added up to 30% more fuel in the v.e. table and it has had no effect. this a s.d.tune. if you take off easy and have the rpm's around 2500 then go wot it will perform great. spraying it with carb spray during the hesitation will make it run correctly. fuel pressure is 58psi during lean condition. any thoughts??

[turbo_bu]

Need to play with the transient (dynamic) fueling tables. \ Engine Calibration \ Fuel \ Dynamics

I would start with the Stomp Compensation table and increase it a little bit at the ECT's your at.

[joecar]

What are the PE enablers and delays set to...?

Post your tune file.

[dian]

Need to play with the transient (dynamic) fueling tables. \ Engine Calibration \ Fuel \ Dynamics

I would start with the Stomp Compensation table and increase it a little bit at the ECT's your at.

having the same issue i went from 0.8 to 2.0 in b3426. no big change. do i have to play with throtle folower before i mess up the impact factor table?

[mecnic99]

sorry for the delay but here is the tune file.

[joecar]

Can you also log GM.EQIVRATIO...

[joecar]

Are you running with MAF, or did you unplug it (your MAF pid show only 2 g/s throughout the log)...?


If you set to fail the MAF (I see C2901 set to 146 Hz), I see you have DTC P0103 set to Not-Reported, so it will never fail the MAF...

and C2903 is set to 6, so it will take 6 consecutive measurements of the MAF frequency exceeding 146 Hz to trigger P0103.


If you don't get a MAF DTC then you are running from the MAF, and the MAF pid shows it is pegged at 2 g/s.

[mecnic99]

no it is s/d and I won't be able to log it again until the weekend.
can't believe I didn't see this.

[joecar]

No worries, it happens...

set C2901 to 1, C2903 to 1, C6001 P0103 to 1-Trip or Non-Emissions..

[mecnic99]

I made the changes that Joecar mentioned and the problem is still there, I installed a different tune from a nearly identical setup and the lean condition is still there. At this point, I think the injectors are not able to keep up with the demand.

[joecar]

So you made sure a MAF DTC was showing up, you added air to the VE table to handle the throttle snap, and same thing happens...?


If you suspect injectors are maxing out, log GM.IBPW1/2 and CALC.INJDC1/2, let's see what the DC% is.

[mecnic99]

sorry for the late reply, the issue was a restricted fuel line. Repaired that and the tune came in near perfect.

Thanks for the help!