DFSO problems

Covers all sn94/95 mustang v8 ecu's.
Trogdor
Posts: 13
Joined: 2021 Feb 21, 15:51
Location: Anna, TX
Vehicle Information: 1993 Mustang 5.0 LX
- B cam
- 76mm C&L with tube for 24 lb injectors
- Old type Ford Motorsport 24 lb injectors
- In fender CAI
- Catted X-pipe
- 2 chamber flows
- 3.73:1 gears
- T5
- T4M0 computer (originally an auto car converted to 5 speed with A9P computer)
- All else is stock

DFSO problems

Unread post by Trogdor »

Hello,

I've been chasing a stalling issue after using the latest CBAZA file. When I push the clutch in sometimes the engine would just die. I started logging to see if it was something obvious and I noticed that the LAMBSE would climb to 2.000 when I let off the gas and the car also felt like it was slowing down much faster. If I push in the clutch while the LAMBSE are at 2.000 the engine would die, if I push in the clutch while the LAMBSE are some normal value, the engine would return to idle. I compare the DFSO values to the ones on the previous CBAZA file and I noticed that there are two parameters that are different

- DFSO Lambse Commanded (LAMBDA) - DFSLAM (Decel Fuel Error), was 1.000 now it's 2.000
- DFSO Lambse Commanded - DFSLAM, was 0.000 now is 1.000

I also noticed that the car is really slow to recover from the DFSO and it almost feels like a have a dead pedal for a couple of seconds, sometimes the engine even pops. This is very pronounced when letting off to enter a turn and trying to apply gas for the exit. There is a distinct delay of when the power comes back on. This issue is not present if the LAMBSE values are somewhat normal (closer to 1.000).

Would returning the values to the previous tune eliminate this behavior?

I understand that DFSO is used to save fuel, and my car could use all the help it can get. I can barely muster 230 miles a tank driving like a normal human being. What would you recommend I try to keep DFSO active and improve the drivability?

Lastly, do I need to make sure DFSO is turned off when I'm logging to exclude false lean data? I know this is done in the GM world. - EDIT, I just looked at the OL/CL flag and I see that it's set at OL so I believe from the right ups that it should not affect the MAF logging.
decipha
Posts: 5031
Joined: 2021 Feb 15, 12:23
Location: Metairie, LA
Vehicle Information: Work Truck
'19 F-150 3.3L

Re: DFSO problems

Unread post by decipha »

yes it will thats why its set to full lean as the wideband will go full lean too

just kick up the dfso min rpm or mph to your liking no problem
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