A9L2 and Crank, Underspeed, Run Fueling (PW)

Vehicle specific forum for tuning the Foxbody Chassis Mustangs utilizing decipha's GUFX Strategy

A9L2 and Crank, Underspeed, Run Fueling (PW)

Unread postby snowdave » Thu Nov 26, 2020 3:45 pm

It's been a while since I have played with the tune on my car, but after some maintenance, I have a noticeable stall right after starting that is shown by 2.25x pulse width. See chart below. I am sure this is something dumb and Decipha's awesome site provides all the answers I need, but my pandemic brain is having a hard time processing this. I also have a short hesitation when I stab the throttle from idle. How does the transition between crank, underspeed & run work? I thought about logging the crkflg and crktmr, but I only confused myself more looking at the ADX file.

Image
snowdave
General Poster
 
Posts: 20
Joined: Mon Aug 27, 2018 8:18 am
Name: Dave
Vehicle Information: 1992 Ford Mustang LX, GUFB, TunerPro RT, Quarterhorse
GT40Ps
TFS Stage 1 Cam
TFS Intake
30lb Injectors
5-speed
3.73 Gears
70mm Edelbrock TB/EGR
Pro-M 80mm MAF
H-pipe / Flowmasters

Re: A9L2 and Crank, Underspeed, Run Fueling (PW)

Unread postby snowdave » Thu Nov 26, 2020 5:05 pm

I am still very interested in the process that transitions between fueling modes, but I suspect my other new issue of random stalls while driving could also be related. I just did a quick drive and the startup graph looks the same as above, but I got data from a stall while driving and it looks similar. It's as if something is happening that is telling the engine to dump a ton of fuel in (if my COVID brain is interpreting this right).

Image
snowdave
General Poster
 
Posts: 20
Joined: Mon Aug 27, 2018 8:18 am
Name: Dave
Vehicle Information: 1992 Ford Mustang LX, GUFB, TunerPro RT, Quarterhorse
GT40Ps
TFS Stage 1 Cam
TFS Intake
30lb Injectors
5-speed
3.73 Gears
70mm Edelbrock TB/EGR
Pro-M 80mm MAF
H-pipe / Flowmasters

Re: A9L2 and Crank, Underspeed, Run Fueling (PW)

Unread postby snowdave » Sat Nov 28, 2020 3:29 pm

Looking through some of the BIN parameters, I noticed:

Cranking Mode Exit Min PIPs : 8
Cranking Mode Exit RPM - NRUN : 650
Cranking Mode Re-enter RPM - NSTALL : 450
Underspeed RPM - UNRPM : 350
Underspeed RPM Hysteresis - UNRPMH : 100

I suspect this means a combination of PIPs and RPM is controlling the fueling mode. I am still looking at how I may be able to tweak the payload to get more detail about the crank/underspeed process. Does it also mean that A9L2 has only two modes as underspeed is slower than cranking?
snowdave
General Poster
 
Posts: 20
Joined: Mon Aug 27, 2018 8:18 am
Name: Dave
Vehicle Information: 1992 Ford Mustang LX, GUFB, TunerPro RT, Quarterhorse
GT40Ps
TFS Stage 1 Cam
TFS Intake
30lb Injectors
5-speed
3.73 Gears
70mm Edelbrock TB/EGR
Pro-M 80mm MAF
H-pipe / Flowmasters

Re: A9L2 and Crank, Underspeed, Run Fueling (PW)

Unread postby snowdave » Sun Nov 29, 2020 9:46 am

Thinking the cold start stall and driving stall may be separate after all. Looking closely at the driving stall and I see MAFV shoots from 1-->2.5V while just coasting along and this is what calls for a ton more fuel to be dumped in, thereby killing the engine. At no other time, including cold start, do I see this odd MAFV discrepancy compared to RPM. I will do some poking around to see if the sensor is dirty or the wiring harness has some type of issue.
snowdave
General Poster
 
Posts: 20
Joined: Mon Aug 27, 2018 8:18 am
Name: Dave
Vehicle Information: 1992 Ford Mustang LX, GUFB, TunerPro RT, Quarterhorse
GT40Ps
TFS Stage 1 Cam
TFS Intake
30lb Injectors
5-speed
3.73 Gears
70mm Edelbrock TB/EGR
Pro-M 80mm MAF
H-pipe / Flowmasters


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