desmaf and isdc?

Decipha's custom GUFX strategy covers all 89-93 foxbody ecu's including the 88 mass-air california ecus.
canuck1
Posts: 67
Joined: 2021 Mar 31, 17:29
Location: Victoria, BC CANADA
Vehicle Information: QH, TunerPro RT 5, GUFX_220418.xdf, A9L2_220405, DECIPHA_220505.ADX, 395w, AFR 195CC Renegade heads, Comp XE274HR cam, Siemens-Deka V 80lb/hr (shorties), Mass-Flo-EFI style 4bbl throttle body with GM maf on top. Custom long tube headers, sidepipes, 5 spd manual.

desmaf and isdc?

Unread post by canuck1 »

I've not been keeping up to date and have only just learned about new method for dialing in idle air in A9L2:
The new file has dashpot and the isc multiplier simplified even further to make dialing in the idle air iscdc extremely simple. How simple? Stupid simple!!!

iscdc = isc multiplier table value

dashpot = +iscdc adder
ipsibr (desmaf_pid_n) = +iscdc adder

The logged dashpot value will be the iscdc added to the base iscdc (the base iscdc is the value in the isc multplier table).
The logged ipsibr correction is the ISCDC correction for adjusting the isc multiplier table. I.E. (ISCDC = ISC Multiplier table + ipsisbr)
An ipsibr value of 0.10 means its adding .10 to the iscdc.

DASHPOT gain value of 0.001 comes out to (TPREL * 0.001) so tprel is the iscdc adder for dashpot.
EX: 750 tprel (wot) * 0.001 == 0.75
at wot, the dashpot value will be 0.75 therefore dashpot is adding 0.75 duty cycle to the isc.

E"XTREMELY SIMPLE. This will make dialing in the base iscdc in the isc multiplier table about as easy as possible. You simply look at the iscdc at a given cell and plug that value in and done.
I have a new dashboard item (DESMAF_PID_N) but there are zeros showing there.

What isc multiplier table do I need to enter values into? Is it FN1861 ISDC Base Targe Neutral/Park (ISC Multiplier) or one of the other variations that are listed?

Any other more explicit tips about how I enter the isdc value at (given run time/temp)?

What role does Desmaf play?

Sean
decipha
Posts: 4956
Joined: 2021 Feb 15, 12:23
Location: Metairie, LA
Vehicle Information: Work Truck
'19 F-150 3.3L

Re: desmaf and isdc?

Unread post by decipha »

0 means no correction

base target or either base target drive if an auto

nope

desmaf is the iscdc
canuck1
Posts: 67
Joined: 2021 Mar 31, 17:29
Location: Victoria, BC CANADA
Vehicle Information: QH, TunerPro RT 5, GUFX_220418.xdf, A9L2_220405, DECIPHA_220505.ADX, 395w, AFR 195CC Renegade heads, Comp XE274HR cam, Siemens-Deka V 80lb/hr (shorties), Mass-Flo-EFI style 4bbl throttle body with GM maf on top. Custom long tube headers, sidepipes, 5 spd manual.

Re: desmaf and isdc?

Unread post by canuck1 »

OK, so I drew up tables in Excel of my ATMR/temp isdc values and it looks like they correspond very closely to whats in the FN1862 ISC multipler base target table. I gues thats why Desmaf is 0, is that correct?

I still would like to lower and stabilize my idle rpm. DSDRPM is 800, but its typically +/- 70 rpm. I'd like to see if I can set it at 750 and maintain within +/- 25 rpm. Will I end up chasing my tail for little gain if I mess with it now? Where should I start if I decide to try?

Sean
decipha
Posts: 4956
Joined: 2021 Feb 15, 12:23
Location: Metairie, LA
Vehicle Information: Work Truck
'19 F-150 3.3L

Re: desmaf and isdc?

Unread post by decipha »

desmaf_pid_n is not desmaf thata two different things

desmaf_pid_n ia the total idle airmass correction same as ipsibr but includes kam and should be near 0

just drop nubase down. if the engine doesnt like it then kick it back up no biggie
canuck1
Posts: 67
Joined: 2021 Mar 31, 17:29
Location: Victoria, BC CANADA
Vehicle Information: QH, TunerPro RT 5, GUFX_220418.xdf, A9L2_220405, DECIPHA_220505.ADX, 395w, AFR 195CC Renegade heads, Comp XE274HR cam, Siemens-Deka V 80lb/hr (shorties), Mass-Flo-EFI style 4bbl throttle body with GM maf on top. Custom long tube headers, sidepipes, 5 spd manual.

Re: desmaf and isdc?

Unread post by canuck1 »

OK, thanks once again. It must be near the minimum at 800, since it won't stabilize at a lower rpm. I'd be OK at 800 if it wasn't over/under shooting that value. I have a good idle air log now, looks very close to right. Is there something I can do to keep idle rpm closer to the actual nubase setting? Maybe raise it further or perhaps alter my spark advance??

Sean
decipha
Posts: 4956
Joined: 2021 Feb 15, 12:23
Location: Metairie, LA
Vehicle Information: Work Truck
'19 F-150 3.3L

Re: desmaf and isdc?

Unread post by decipha »

nope nothing

idle is a primarily a mechanical aspect of an engine combo so if its not stable then the engine dont want it
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