Going rich then lean when shifting

Covers all sn94/95 mustang v8 ecu's.
dleach1407
Posts: 468
Joined: 2021 Mar 21, 15:17
Location: Colorado Springs, CO
Vehicle Information: 95 Mustang GT, CBAZA Quarterhorse
331, 190 11R heads, Edelbrock Victor 50 manifold, F303, T5, 76mm Turbo, 91 octane, Returnless dual pump 03 cobra tank, Behind bars rails, 80# siemens injectors
wbo2_030MtxL

57 F100, RZASA, 04 Crown Vic ecu and harness, 302, GT40 heads, 4r70w, 80# deka5 shorties, Holley carb style throttle body, Speedmaster high rise intake manifold

Re: Going rich then lean when shifting

Unread post by dleach1407 »

Thank you for the explanation. Most of the functions i listed are either blank, or the comment is just the function number. FN1321, 1322al/dl are good examples of that. With my manifold volume at 3.25, its pretty dialed in. The tip in stays in the high 14s to low 15s but I still get the lean spike for a split second right before snapping back to normal AFRs after shifting. This is where i am stuck because moving manifold volume either makes it too rich or too lean on tip in. Changing manifold volume isnt resolving the issue so Im not sure where to go. I feel this is the 95% youre talking about. I believe at this point, I need to mess with the accel time constant to lengthen the time the transient fuel time for just a little longer than it does now. I believe that will get rid of the lean spike. Im assuming I would increase decel if its going rich on tip out and reduce it if is going lean on tip out and I would probably adjust it after getting accel time constant dialed in. Am i on the right track?
dleach1407
Posts: 468
Joined: 2021 Mar 21, 15:17
Location: Colorado Springs, CO
Vehicle Information: 95 Mustang GT, CBAZA Quarterhorse
331, 190 11R heads, Edelbrock Victor 50 manifold, F303, T5, 76mm Turbo, 91 octane, Returnless dual pump 03 cobra tank, Behind bars rails, 80# siemens injectors
wbo2_030MtxL

57 F100, RZASA, 04 Crown Vic ecu and harness, 302, GT40 heads, 4r70w, 80# deka5 shorties, Holley carb style throttle body, Speedmaster high rise intake manifold

Re: Going rich then lean when shifting

Unread post by dleach1407 »

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m-barans
Posts: 88
Joined: 2021 Feb 16, 23:09
Location: Lafayette, Oregon US
Vehicle Information: 2003 Mercury Marauder 300A with new stock bore IRON 4.6 block, Manley crank, Manley H-tuff h-beam rods, CP pistons with stainless rings, ARP head studs, GT500 lash adjusters and rollers, D series cylinder heads, VMP GEN3R 2.65 L TVS blower, 80 lb/hr FRPP Siemens Deka injectors, HPX slot 100mm MAF, coyote mustang fuel pump with Holley 60 psi filter/regulator return at pump, Stainless works long tube headers and complete exhaust, Moates quarter horse and TunerPro RT with support from Decipha, RZASA strategy.

2001 Ford Lightning SVT F-150 stock engine w/ inlet ported M112, GT500 rollers, ARP head studs, metco quick change upper pulley with stock sized upper, K&N intake system, bassani SS exhaust system from the stock manifold flanges back. 4x4 trans oil pan. SSBC big brakes 14” up front. Work/Street truck. My “next to build” with trick flow heads (before extinction) with h-beams & cobra jet crank (sitting in tool box) and proper pistons. Next up after the marauder is dialed in.

Re: Going rich then lean when shifting

Unread post by m-barans »

Ok, I’m not sure I can be helpful here but reading this I’m just thinking maybe we are fighting a mechanical system and/or a parameter in the tune

A: Possible injector lag (mechanical) I have no idea how this can be discovered outside of replacements

B: Possible MAF reversion (mechanical) record MAF data log

C: Possible Fuel pressure fluctuation (mechanical) monitor/ record fuel pressure either mechanically or via input if available

D: Transient Condition Functions (electronic control) Obviously that’s why we are here and I’m just cutting my teeth with basic tuning so I lack something to add here.

I hope maybe this might help
dleach1407
Posts: 468
Joined: 2021 Mar 21, 15:17
Location: Colorado Springs, CO
Vehicle Information: 95 Mustang GT, CBAZA Quarterhorse
331, 190 11R heads, Edelbrock Victor 50 manifold, F303, T5, 76mm Turbo, 91 octane, Returnless dual pump 03 cobra tank, Behind bars rails, 80# siemens injectors
wbo2_030MtxL

57 F100, RZASA, 04 Crown Vic ecu and harness, 302, GT40 heads, 4r70w, 80# deka5 shorties, Holley carb style throttle body, Speedmaster high rise intake manifold

Re: Going rich then lean when shifting

Unread post by dleach1407 »

I do not have injector lag issues. My injectors are genuine siemens injectors purchased from a trusted siemens dealer. They probably have less than 10k miles on them. I believe I use the same vendor Decipha uses. The lag that Decipha describes earlier in this thread does not seem describe the issue i am experiencing.

My maf is pretty far from the throttle body down in the fender well. I do not believe maf reversion is the issue.

I have an AEM fuel pressure gauge and monitor fuel pressure. I also have a fuel pressure dampener on my rails which counteracts any weird spikes. My fuel pressure is definitely stable. The whole fuel system was revamped last year but Ive been having the issue much longer.

The lean condition and seriousness of the lean condition changed when I updated my transient settings with settings from the most recent .bin. Changing manifold volume has made significant changes and almost resolved the issue. its 95% there. These are all improvements after messing with transient fuel that I havent been able to make any real progress on in 3 years. Im pretty sure I just need to extend the transient fuel constants to fix it. Im off for the next 4 days and going to mess with it to see if I can get it dialed in.
dleach1407
Posts: 468
Joined: 2021 Mar 21, 15:17
Location: Colorado Springs, CO
Vehicle Information: 95 Mustang GT, CBAZA Quarterhorse
331, 190 11R heads, Edelbrock Victor 50 manifold, F303, T5, 76mm Turbo, 91 octane, Returnless dual pump 03 cobra tank, Behind bars rails, 80# siemens injectors
wbo2_030MtxL

57 F100, RZASA, 04 Crown Vic ecu and harness, 302, GT40 heads, 4r70w, 80# deka5 shorties, Holley carb style throttle body, Speedmaster high rise intake manifold

Re: Going rich then lean when shifting

Unread post by dleach1407 »

So no matter what i set manifold volume to. I still get the lean spike after shift and it's worse the higher the rpm is before i shift when cold. If i shift at low rpm it barely happens. If i shift at 3krpm, it leans out to 1.16, at 4k, 1.20. thoughts of other things i can try? It's like the tip isn't happening for long enough because it doesn't go lean right away. Accel time constant is already close to max in a few cells, can i bump up the xmul so i can decrease the Accel/decel time constant tables to get more adjustability?
dleach1407
Posts: 468
Joined: 2021 Mar 21, 15:17
Location: Colorado Springs, CO
Vehicle Information: 95 Mustang GT, CBAZA Quarterhorse
331, 190 11R heads, Edelbrock Victor 50 manifold, F303, T5, 76mm Turbo, 91 octane, Returnless dual pump 03 cobra tank, Behind bars rails, 80# siemens injectors
wbo2_030MtxL

57 F100, RZASA, 04 Crown Vic ecu and harness, 302, GT40 heads, 4r70w, 80# deka5 shorties, Holley carb style throttle body, Speedmaster high rise intake manifold

Re: Going rich then lean when shifting

Unread post by dleach1407 »

Anyone?
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