Surging and Stalling while in Closed Loop & MAF Tuning at Idle

[nitrousgp]

I've recently started to work on my truck tuning and am running into an issue where I seem to be chasing my tail, so I'm sure I'm missing something. I've attached a short scan during initial start-up when the truck stalls immediately after the idle drops to the base idle set point.

Truck info:
- 5.3L
- VSR 80mm
- LS9 MAP sensor
- Truck Norris cam
- Fuel Injector Connection 850cc injectors

For some background, the truck was originally tuned a while ago by a certain tuning company that many have said is hardly worth the money (I wish I had known), but mostly because I really just didn't have the time to play with the tune. Something I always wondered was if the injector data in the tune was accurate. I questioned the tuning company because the injector data from Fuel Injector Connection doesn't seem to jive with what's in the tune, but the truck ran alright for the most part. That being said, maybe the injector data is incorrect and that's why I seem to be battling myself. I've attached the injector as well.

I'm trying to tune the MAF, but it seems when I make an adjustment (leaner or richer) at idle, the truck wants the opposite in the next scan. For instance, if I lean out the MAF 5% because my MAF error % scan is showing it being rich, it seems the next scan the truck is very lean and needs to be richened back up in the same cells. The truck runs very close to 1.0 lambda while cruising, it seems the main issue is while coming to a stop and/or just idling that it surges and wants to stall. In my attached scan the truck is in start-up and then stalls immediately once it transfers to the base idle set point.

Would anyone mind looking over my tune and scan and see if I am missing something or why I could be chasing my tail while tuning the MAF?

Thanks.

[Alvin]

I've recently started to work on my truck tuning and am running into an issue where I seem to be chasing my tail, so I'm sure I'm missing something. I've attached a short scan during initial start-up when the truck stalls immediately after the idle drops to the base idle set point.

Truck info:
- 5.3L
- VSR 80mm
- LS9 MAP sensor
- Truck Norris cam
- Fuel Injector Connection 850cc injectors

For some background, the truck was originally tuned a while ago by a certain tuning company that many have said is hardly worth the money (I wish I had known), but mostly because I really just didn't have the time to play with the tune. Something I always wondered was if the injector data in the tune was accurate. I questioned the tuning company because the injector data from Fuel Injector Connection doesn't seem to jive with what's in the tune, but the truck ran alright for the most part. That being said, maybe the injector data is incorrect and that's why I seem to be battling myself. I've attached the injector as well.

I'm trying to tune the MAF, but it seems when I make an adjustment (leaner or richer) at idle, the truck wants the opposite in the next scan. For instance, if I lean out the MAF 5% because my MAF error % scan is showing it being rich, it seems the next scan the truck is very lean and needs to be richened back up in the same cells. The truck runs very close to 1.0 lambda while cruising, it seems the main issue is while coming to a stop and/or just idling that it surges and wants to stall. In my attached scan the truck is in start-up and then stalls immediately once it transfers to the base idle set point.

Would anyone mind looking over my tune and scan and see if I am missing something or why I could be chasing my tail while tuning the MAF?

Thanks.

I didn't do this but.. in defense of your tuner on the injector data.. I intentionally don' use some seller's data because I have better sources else where. That may have been your tuners intention there.

It doesn't look like the VVE has been tuned. In fact the VVT modifiers are still there and that came doesn't use VVE.

I would start by dumping in the correct data, at least temporarily disablng the MAF and tune this in speed density. It can likely use a bit more final idle airflow minimum table.


The log you posted didn't look excessively rich or lean.