Misfire at low loads

Decipha's custom GUFX strategy covers all 89-93 foxbody ecu's including the 88 mass-air california ecus.
lugbolt
Posts: 34
Joined: 2021 Feb 15, 19:03
Location: central arkansas
Vehicle Information: 1992 ford mustang gt A9P 10.5:1 pump gas 408"w AFR205 T56 Magnum 8.8/3.73

Re: Misfire at low loads

Unread post by lugbolt »

m-barans wrote: 2021 May 22, 17:04 Exhaust leaks could explain the bias in fueling for bank 1 vs bank 2. If you have a misfire(s) on one bank it can throw off that banks fuel trim (rich) as well. If I had to guess it’s probably an ignition system related misfire on that (richer) bank.
thank you for posting this. I never once gave a second thought to it but while trying to do a log on mine I noticed a bias on the right bank. Did a smoke test, sure enough leaks everywhere that I didn't work on. Odd. Usually it's me screwing stuff up. Unfortunately it also means that I will probably have to buy a set of headers. Always something.
bad86capri
Posts: 163
Joined: 2021 Feb 16, 10:09
Location: Knoxville, TN
Vehicle Information: 1986 Capri 306, Twisted Wedge heads, RPM II Intake, Anderson B3 cam, 80Lbs Siemens Injectors, MAC Longtube Headers, G-Force T5, Spec 6 Puck Clutch, Ford Racing Aluminum Driveshaft.

Re: Misfire at low loads

Unread post by bad86capri »

Brewster wrote: 2021 Jun 14, 22:54 Still haven't had a chance to finish this one, customer opted to come grab his car and replace his intake manifold himself. When he's done with that I'm sure he ll bring it back and I can continue onward and upward.

I've noticed any cammed fox's I've played with usually have a bit of a miss while cruising or low loads. I've always inspected the ignition systems and never find any issues there, not sure if there just running a little lean and don't like it, a characteristic with a cam or what it could be.

Hows your trims when yours starts messing around?
I didnt check the trims when i started. this definitely isnt a small miss. if im 5th gear it bucks so hard that it feels like its going to break rearend! i finally got everything to install the 90m lightning maf. so im going to start with a fresh tune. im hoping the issue is in my current tune. if not then back to troubleshooting. one more thing to note, during acceleration with around half throttle it goes really rich to around 11.0 then leans back out to whats commanded.
Brewster
Posts: 92
Joined: 2021 May 15, 15:59
Location: Edmonton, Alberta, Canada
Vehicle Information: 1992 Mustang LX
347 Cui
AFR 185

Re: Misfire at low loads

Unread post by Brewster »

Post a log and your file, helps us all learn together!
bad86capri
Posts: 163
Joined: 2021 Feb 16, 10:09
Location: Knoxville, TN
Vehicle Information: 1986 Capri 306, Twisted Wedge heads, RPM II Intake, Anderson B3 cam, 80Lbs Siemens Injectors, MAC Longtube Headers, G-Force T5, Spec 6 Puck Clutch, Ford Racing Aluminum Driveshaft.

Re: Misfire at low loads

Unread post by bad86capri »

Brewster wrote: 2021 Jun 22, 22:05 Post a log and your file, helps us all learn together!
Do you have binary editor?
bad86capri
Posts: 163
Joined: 2021 Feb 16, 10:09
Location: Knoxville, TN
Vehicle Information: 1986 Capri 306, Twisted Wedge heads, RPM II Intake, Anderson B3 cam, 80Lbs Siemens Injectors, MAC Longtube Headers, G-Force T5, Spec 6 Puck Clutch, Ford Racing Aluminum Driveshaft.

Re: Misfire at low loads

Unread post by bad86capri »

Ill post up when i get home from work.
Brewster
Posts: 92
Joined: 2021 May 15, 15:59
Location: Edmonton, Alberta, Canada
Vehicle Information: 1992 Mustang LX
347 Cui
AFR 185

Re: Misfire at low loads

Unread post by Brewster »

Yea I have BE as well. Haven't used it in a long time tbh lol
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