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

Going rich then lean when shifting

Unread post by dleach1407 »

The issue is much more prominent when cold but I am still chasing the issue I have been having for years. We have talked about this multiple times and have not been able to figure it out. If I remember correctly. PaulC-Turbo5.0 is also having this same issue with his 94/95 tune.

As a refresher, here is what the car does.

When the car is not warm, when I shift, as the RPMs come down, it goes to about 12.1 AFR, then when I shift, it goes up to 18 or higher. The higher the rpm before I shift, the worse the swing is. If i bring it up to say 5k before I shift, the AFR will drop all the way to 22, the car misfires for a second, then the AFR starts to drop down to normal. After the car is fully up to temp, it does not drop the AFR way down to 22 but I still see AFR of 16-17 when i shift.

Some things I have noticed. During initial startup my car idles at 12 AFR and slowly rises as the car warms up. Once warm, it bounces between 14.3 and 15.5 AFR. Ive played with the enrichment which doesnt seem to change the AFR much at idle when cold. I did change the fuel system out and my fuel trims are a little off even though I set the fuel pressure to 39 with the vacuum disconnected from the regulator. I should have that dialed in over the next day or 2. I drove around today and got them much closer. My idle range maf correction was at 91.9 so it was way off. Im going to lock the car in open loop tomorrow and get idle AFR right at 14.5 after its nice and warm so I have the fuel perfect at idle up to 1000rpm. I would really like to figure out a way to disable the adaptives at idle to 1k if possible. My HEGO is in the down pipe a couple inches from the turbo outlet but it still cools off while idling and I can see the LTFT sway because of long idle times. If I am in a drive thru, (chic fil a takes forever here) its not uncommon for the LTFT to change 8 to 10% which is a huge swing in my opinion.

In the past you had me check a couple things. You asked me to change the time before it goes into closed loop which did not help but unfortunately since we lost the old board DB, I cant go back and find everything I checked.

Is there a Tip in/Tip out setting for fuel that change the way it acts when i get off the gas and press the gas after a shift, kind of like an accelerator pump in a carb? When the car is in open loop after start up, are LTFTs applied or does it ignore them until the car goes into closed loop?
PaulC-turbo5.0
Posts: 104
Joined: 2021 Feb 15, 21:56
Location: Lancaster New York
Vehicle Information: 1989 fox GT convertible
5.0 stock block, E7 heads, stock cam
Explorer GT40 intake flipped to driver side inlet
Single 67mm On3 BB turbo
Flipped JBA headers, custom SS 2.5" hotside built by me
custom 3" coldside thru On3 intercooler
tuning with Moates QH + TPRT
Dechipa's GUFX and supporting files, couldnt have tuned it myself without him!

Re: Going rich then lean when shifting

Unread post by PaulC-turbo5.0 »

I do still have this issue but it has improved by kicking up aem to 2 and then I have also multiplied the lower part of the accel enrichment table in the lower temp areas. It will still go leaner then I want but it doesn’t break up now at least. With my car I’ve noticed it’ll also do it with added load not while shifting. If I round a corner in second when I come out of it and apply throttle it will give off the same symptoms. Also I’m using gufx cuz I have a fox body
decipha
Posts: 4950
Joined: 2021 Feb 15, 12:23
Location: Metairie, LA
Vehicle Information: Work Truck
'19 F-150 3.3L

Re: Going rich then lean when shifting

Unread post by decipha »

OP it sounds like you need to go cut your manifold volume down

paul it sounds like u need to kick up your transient accel multiplier
PaulC-turbo5.0
Posts: 104
Joined: 2021 Feb 15, 21:56
Location: Lancaster New York
Vehicle Information: 1989 fox GT convertible
5.0 stock block, E7 heads, stock cam
Explorer GT40 intake flipped to driver side inlet
Single 67mm On3 BB turbo
Flipped JBA headers, custom SS 2.5" hotside built by me
custom 3" coldside thru On3 intercooler
tuning with Moates QH + TPRT
Dechipa's GUFX and supporting files, couldnt have tuned it myself without him!

Re: Going rich then lean when shifting

Unread post by PaulC-turbo5.0 »

Driving the car this morning and I decided to put the accel table back to original and kicked up both transient multipliers to 2 and it seemed to be better.
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 »

decipha wrote: 2021 May 01, 10:06 OP it sounds like you need to go cut your manifold volume down
That would make sense. I have a victor 5.0/Victor EFI manifold and its significantly shorter than a stock manifold. The volume is probably considerably less. Will this also help with the cold HEGO issue I experience during longer idle sessions?
decipha
Posts: 4950
Joined: 2021 Feb 15, 12:23
Location: Metairie, LA
Vehicle Information: Work Truck
'19 F-150 3.3L

Re: Going rich then lean when shifting

Unread post by decipha »

lmao manifold volume has nothing to do with the size of the intake manifold lol. Its a global modifier to transient fuel.

No cold hego means its in closed loop too soon. Some engines takes 4 minutes or more before they can go in to closed loop correctly.
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 »

The car can be running for hours. If I idle for a long time, the trims start to change. I believe this mostly has to do with the fact its so far away from the exhaust manifold. Its kind of close to the pass side manifold but the drivers side has a crossover and its pretty far away. The O2 is new and a NTK which from what I read is OEM.
decipha
Posts: 4950
Joined: 2021 Feb 15, 12:23
Location: Metairie, LA
Vehicle Information: Work Truck
'19 F-150 3.3L

Re: Going rich then lean when shifting

Unread post by decipha »

yep thats normal and you should kick her in to open loop after idling for an excessive time to remedy that.
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 »

Is there a write up that includes manifold volume/transient fuel and what I would adjust? Havent looked it up in the tune yet as im working on my truck today but I want to look at it later tonight. It looks like you answered what to adjust to kick it into open loop when idling in my ltft thread. Thanks!
decipha
Posts: 4950
Joined: 2021 Feb 15, 12:23
Location: Metairie, LA
Vehicle Information: Work Truck
'19 F-150 3.3L

Re: Going rich then lean when shifting

Unread post by decipha »

no i sure dont

you can go divide it in half and go from there with her
Post Reply