stock and idle issues

Decipha's custom GUFX strategy covers all 89-93 foxbody ecu's including the 88 mass-air california ecus.
gcc522
Posts: 15
Joined: 2024 Sep 01, 14:43
Location: Los Angeles, California, USA
Vehicle Information: 1987 / Ford / Mustang /GT
A9L
1990 MAF conversion
Cobra 1.7: roller rockers
1.5" shorty headers
2.5" cat-back
M-2300-K brakes
Contex/IPS grand Sport front and rear suspension

Re: stock and idle issues

Post by gcc522 »

No reds on the dash, just the FUEL_APT_LAST going yellow to -1 occasionally. And the WB-1ER_AEMEUG is yellow all the time, showing 0.65.

I get that when I hover my cursor over a parameter in Tunerpro, it will flash up documentation about that parameter. Is there some place on the web site where all this documentation is stored? If so, I must be missing it somehow. I'd like to look through as much of them as I can.

thanks
decipha
Posts: 6297
Joined: 2021 Feb 15, 12:23
Location: Metairie, LA
Vehicle Information: Work Truck
'25 F-150 5L

Re: stock and idle issues

Post by decipha »

yeah on the homepage, payloads

apt going to -1 occasionally is a major problem

you need to fix that before you can even think about doing anything idle related
gcc522
Posts: 15
Joined: 2024 Sep 01, 14:43
Location: Los Angeles, California, USA
Vehicle Information: 1987 / Ford / Mustang /GT
A9L
1990 MAF conversion
Cobra 1.7: roller rockers
1.5" shorty headers
2.5" cat-back
M-2300-K brakes
Contex/IPS grand Sport front and rear suspension

Re: stock and idle issues

Post by gcc522 »

According to the reference, the FUEL_APT_LAST is the "last value" stored..., and =-1 indicates closed throttle. That does happen quite a bit when I'm driving around town.

I guess I don't understand what that number is really indicating. Can you elaborate?
decipha
Posts: 6297
Joined: 2021 Feb 15, 12:23
Location: Metairie, LA
Vehicle Information: Work Truck
'25 F-150 5L

Re: stock and idle issues

Post by decipha »

-1 is closed throttle, if its doing it occasionally then thats an issue

if its not -1 everytime at closed throttle then the ecu doesnt know your at closed throttle
PaulC-turbo5.0
Posts: 118
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: stock and idle issues

Post by PaulC-turbo5.0 »

been following along on this and figured ill chime in to try to help

-1 is closed throttle, 0 is part throttle, and 1 is wide open throttle. any time you have your foot off the pedal the dash should read -1. anytime you are cruising with your foot on the pedal it should read 0. anytime you mash the pedal it should read 1. If it is occasionally flashing to -1 while cruising with your foot on the pedal it indicates an issue. If its only flashing to -1 when you release the pedal then its operating correctly. anytime you are idling it should read -1 and stay there.

if its following whats posted above and there has just been confusion with the wording my guess is your hanging idle issues could be dashpot needing adjustments. when I first switched over to Decipha's stuff and tunerpro I had similar issues and they were dashpot related.
gcc522
Posts: 15
Joined: 2024 Sep 01, 14:43
Location: Los Angeles, California, USA
Vehicle Information: 1987 / Ford / Mustang /GT
A9L
1990 MAF conversion
Cobra 1.7: roller rockers
1.5" shorty headers
2.5" cat-back
M-2300-K brakes
Contex/IPS grand Sport front and rear suspension

Re: stock and idle issues

Post by gcc522 »

Thanks Michael, Paul, for your inputs. I had to deal with some other issues so I could not work on my car for a while.

I made more adjustments on the idle stop screw to try to get ISCDTY down to between 0.15 and 0.35. I don't think it goes below 0.28, even as I bottomed out the screw to where the spring bound up. I did this by stopping and starting the engine each time, and settled on an opening where the ISCDTY JUST floats above 0.28 at idle. It seems to be idling steadily at around 700 rpm now.

The DESMAF_PID_N does not want to settle between -0.1 and + 0.1. It starts out at 0.5x and slowly drops to -0.3x after a couple minutes of idling. How important is it to keep this between -0.1 and +0.1?

I realize this is step 0 of many steps to tuning my new engine, but I'm still learning. If I set a new value for ITHBMA, how do I "poke" it into the running parameters? In the PROM read/write utility, the "Program chip" button is greyed out when the engine is running.
decipha
Posts: 6297
Joined: 2021 Feb 15, 12:23
Location: Metairie, LA
Vehicle Information: Work Truck
'25 F-150 5L

Re: stock and idle issues

Post by decipha »

thata debyma clipping it

that desmaf correction is fine, after you have it all situated the isc multiplier table is where youll apply all idle air corrections

you need to enable emulation, change the value and hit the blue update icon that will only appear when your emulating

i think its listed in the getting started write up, if not LMK
gcc522
Posts: 15
Joined: 2024 Sep 01, 14:43
Location: Los Angeles, California, USA
Vehicle Information: 1987 / Ford / Mustang /GT
A9L
1990 MAF conversion
Cobra 1.7: roller rockers
1.5" shorty headers
2.5" cat-back
M-2300-K brakes
Contex/IPS grand Sport front and rear suspension

Re: stock and idle issues

Post by gcc522 »

Thanks Michael.

I don't know what this means:

"thata debyma clipping it"

Is it normal for my ISCDTY to never drop below 0.28?

Should I back off the throttle stop so it's not always stuck at 0.28 when idling?
decipha
Posts: 6297
Joined: 2021 Feb 15, 12:23
Location: Metairie, LA
Vehicle Information: Work Truck
'25 F-150 5L

Re: stock and idle issues

Post by decipha »

debyma is set to 0.12 lbs that clips the minimum isc airmass to 28% duty cycle from the fn800 iscdc lookup
gcc522
Posts: 15
Joined: 2024 Sep 01, 14:43
Location: Los Angeles, California, USA
Vehicle Information: 1987 / Ford / Mustang /GT
A9L
1990 MAF conversion
Cobra 1.7: roller rockers
1.5" shorty headers
2.5" cat-back
M-2300-K brakes
Contex/IPS grand Sport front and rear suspension

Re: stock and idle issues

Post by gcc522 »

After a pause, getting back to trying understand TPRT and A9L2.

My totally stock engine is still having the same issues running the A9L2 bin. To recap:

- have set idle stop screw to get 0.28 ISCDTY
- have set NUBASE to 700
- cold idle seems to behave after a little bit of stumbling right after cold start
- idle creeps up to 1100 rpm after the engine warms up and hunts
- transient response sometimes stumbles and backfires

Found this in A9L2 through TPRT:

SP** (WARNING) AHISL - Injector High Slope **SEE COMMENTS** 19.641 lbs/hr (= 1.0337 * 19 lb/hr)
SP** (WARNING) AHISL - Injector High Slope (lbs/sec) **SEE COMMENTS** .00545573 lbs/sec (consistent)
Are you referring to comments on this page:

http://efidynotuning.com/fuel.htm

SP** ALOSL - Injector Los Slope [lbs/hr] 26.099 lb/hr (= 1.3736 * 19 lb/hr)
SP** Injector Low Slope - ALOSL - [lbs/min] 0.0072496 lb/min. Label says "lb/min", but value says lb/sec. Which is correct?


With my new engine with bigger HCI, I plan to use the Ford Green Top 42 lb/hr injectors. The specs on this page:

http://efidynotuning.com/injdata.htm

Says:

K-Constant 30.00
High Slope 43.009 (= 42 * 1.0260)
Breakpoint 0.0000212
Low Slope 46.066 (= 42 * 1.0968)

Are these still accurate?

TIA
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