"Fuel_In_Sync" Error? - Engine Missing at High RPM

Decipha's custom GUFX strategy covers all 89-93 foxbody ecu's including the 88 mass-air california ecus.
GT-FordyP
Posts: 2
Joined: 2021 Dec 18, 11:36
Location: Denver, Co
Vehicle Information: 1990 Ford Mustang GT A9L. Explorer motor with old school Paxton Novi 1000 supercharger.

"Fuel_In_Sync" Error? - Engine Missing at High RPM

Unread post by GT-FordyP »

I'm having trouble diagnosing a datalog and my engine missing at roughly 4800rpm.
  • At high RPM (WOT and CL) the engine stops making power at 4800rpm and falls to around 4000rpm before building to 4800rpm and repeating the cycle.
  • At these specific times the datalog column of "FUEL_IN_SYNC" stops reading "sequential fire" and is blank for a few sample Counts
  • Datalog column FUELPW1 also increases by a factor of three occasionally when this issues happens
Any suggestions on what to look at? Is it tune related? I swapped out the distributor today (different TFI and pip) and had similar results. Car is also supercharged.
Attachments
April7Log new dist.xdl
Log from 4/7/22 - Sample#3580 is not "sequential fire"
(699.52 KiB) Downloaded 124 times
A9L2_210217_Dec27_DEKA_MAF5.bin
Current Tune on Car
(56 KiB) Downloaded 131 times
decipha
Posts: 4958
Joined: 2021 Feb 15, 12:23
Location: Metairie, LA
Vehicle Information: Work Truck
'19 F-150 3.3L

Re: "Fuel_In_Sync" Error? - Engine Missing at High RPM

Unread post by decipha »

yep your hitting the 2 step.

I inverted the clutch input to the 2 step.

btw your doing an excellent job dialing in the maf, keep it up.
Attachments
GTFordy_220409a_2step.bin
(56 KiB) Downloaded 123 times
GT-FordyP
Posts: 2
Joined: 2021 Dec 18, 11:36
Location: Denver, Co
Vehicle Information: 1990 Ford Mustang GT A9L. Explorer motor with old school Paxton Novi 1000 supercharger.

Re: "Fuel_In_Sync" Error? - Engine Missing at High RPM

Unread post by GT-FordyP »

UPDATE UPDATE UPDATE - Problem Fixed

Let this be a lesson to anyone who has been copy and pasting their tunes on each A9L2 update over the years. I think my base tune is from a 2016 version of A9L2 and I've been casually copying and pasting my tune until now when updates are released. It finally bit me when I did a deep dive on the latest A9L2 to look at what was different and If I had missed something or accidently setup anything wrong.

Turns out on a few of my latest tunes the "Perload Switch - PRLDSW" was incorrectly checked/selected. I'm not sure when I accidently checked it, but when the car hit boost and load = 100% bad things were starting to happen, now that load is being correctly calculated as load/peak load the car runs great.

edit: i also found that the two step RPM was set at 4875 and raised it to the latest values i saw in the current A9L2.
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