Idle stability control in A1C

A1C calibration can be modified and configured to operate all EFI-SD4x ECUs in 4 cylinder, 6 cylinder and 8 cylinder configurations.
Sevensecondsuv
Posts: 111
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Location: North Central IL
Vehicle Information: 1994 F-350 CCLB 7.5/ZF/4wd
1995 F-250 RCLB 4.9/T18/4wd
2000 Excursion 6.8/4R100/4wd
2001 Ranger RCSB 2.3/M5OD/2wd - turbocharged
2007 Town Car 4.6/4R75E
2011 Ranger SCSB 2.3/M5OD/2wd
wbo2_aem_uego

Idle stability control in A1C

Unread post by Sevensecondsuv »

I'm trying to figure out the idle issues with my tune. This started as one Decipha was working on for me, so it uses his "mechanical idle" patch rather than Ford's standard IAC parameters. I'm trying to figure out how exactly the ISC fuel control works and what each parameter does.

The "warm idle" write up touches on ISC, but is not complete enough for my dense brain to fill in the gaps and make sense out of it.

If anyone could post a basic overview of how ISC fuel control functions that would be very helpful. I'm specifically wondering:
1) how it interacts with closed loop fueling since ISC fuel would seem to just cause a fuel trim error if the VE table is accurate
2) what the ISC flags mean in the datalog - I see it jumping between 0, 1, and 2
3) how to dial in the idle cells of the VE table without ISC throwing things off
4) how to approach changing the ISC parameters in the tune

I realize that's a tall order because the the speed density strats are the extreme minority around here, but any help would be appreciated. I need to get this tune finished and the truck back driving.
efloth
Posts: 274
Joined: 2021 Feb 15, 22:12
Location: Sacramento CA
Vehicle Information: 1991 F150 4.9L J1X 80lb Injectors E85
1995 F150 5.8L MOB1

Re: Idle stability control in A1C

Unread post by efloth »

Does your idle still surge with the IAC unplugged? Are you sure it's not defective? I had issues getting mine dialed in until I finally replaced the IAC and things were much better.
Sevensecondsuv
Posts: 111
Joined: 2021 Nov 08, 22:24
Location: North Central IL
Vehicle Information: 1994 F-350 CCLB 7.5/ZF/4wd
1995 F-250 RCLB 4.9/T18/4wd
2000 Excursion 6.8/4R100/4wd
2001 Ranger RCSB 2.3/M5OD/2wd - turbocharged
2007 Town Car 4.6/4R75E
2011 Ranger SCSB 2.3/M5OD/2wd
wbo2_aem_uego

Re: Idle stability control in A1C

Unread post by Sevensecondsuv »

No, the surge is gone once it settles. It runs the same with our without the IAC plugged, which tells me I could probably close the throttle stop a little more. Now it just does weird things like goes offscale lean as it approaches idle from decel and then takes a few seconds of running like garbage before ISC steps in to fix it. Also, coming out of idle it will sometimes go so rich it almost stalls. I think this is because the 1000-rpm / high-load cells in the VE table are massively rich, but I'm hesitant to start changing things until I understand what I'm doing.

Here's a screen shot of the VE table. Obviously it needs some work in the idle region.
IMG_20221211_135004959.jpg
efloth
Posts: 274
Joined: 2021 Feb 15, 22:12
Location: Sacramento CA
Vehicle Information: 1991 F150 4.9L J1X 80lb Injectors E85
1995 F150 5.8L MOB1

Re: Idle stability control in A1C

Unread post by efloth »

What values do you have for engine displacement? It's something like sachrg and basemd I think. I used the values from J1X in A1C and had it running pretty good. You will have to dial in the ve table again if you try this though.
Sevensecondsuv
Posts: 111
Joined: 2021 Nov 08, 22:24
Location: North Central IL
Vehicle Information: 1994 F-350 CCLB 7.5/ZF/4wd
1995 F-250 RCLB 4.9/T18/4wd
2000 Excursion 6.8/4R100/4wd
2001 Ranger RCSB 2.3/M5OD/2wd - turbocharged
2007 Town Car 4.6/4R75E
2011 Ranger SCSB 2.3/M5OD/2wd
wbo2_aem_uego

Re: Idle stability control in A1C

Unread post by Sevensecondsuv »

I'd have to look. It was 305 cubes (actual engine displacement) last I looked. However, Decipha did "scale" the tune in an attempt to get the injectors to play nice, so that might have changed. One of the frustrations of A1C is that it only uses a single slope parameter for the injectors so the Ford-supplied hi/lo slope values for the coyote injectors doesn't produce acceptable results at low rpm/load. I think this searching for a workable combo of single slope and offset is what was driving most of the idle issues - hard to get things dialed in if the injector model is off.

Question for you though: how exactly do I enable emulate so I can make changes "live"? Also, how to I enable the trace feature in TP so I can see where in the VE table it's running?
efloth
Posts: 274
Joined: 2021 Feb 15, 22:12
Location: Sacramento CA
Vehicle Information: 1991 F150 4.9L J1X 80lb Injectors E85
1995 F150 5.8L MOB1

Re: Idle stability control in A1C

Unread post by efloth »

Oh yes, that could be your core issue. I'm running the deka 80s that Michael suggested since they have a mostly linear slope.

In preferences make the data acquisition tab look like this:
image001 (1).png
Turning on tracing requires that you select the data types for each desired parameter in the xdf. It takes a bit of time but it's easy work. There's a nice guide out there if you Google for it. Michael does not select them since he doesn't use data to tracing normally.
Sevensecondsuv
Posts: 111
Joined: 2021 Nov 08, 22:24
Location: North Central IL
Vehicle Information: 1994 F-350 CCLB 7.5/ZF/4wd
1995 F-250 RCLB 4.9/T18/4wd
2000 Excursion 6.8/4R100/4wd
2001 Ranger RCSB 2.3/M5OD/2wd - turbocharged
2007 Town Car 4.6/4R75E
2011 Ranger SCSB 2.3/M5OD/2wd
wbo2_aem_uego

Re: Idle stability control in A1C

Unread post by Sevensecondsuv »

Yeah, at this point if I'm going to spend more money it's going to be on a PIMPx / megasquirt, not a different set of injectors. With Moates going away, it appears these old EECs are at a bit of a dead end - not sure I want to invest in them further at this point, either $ or time/learning.

I spent a good three hours yesterday reading through Michael's writeups and going through the BIN, just trying understand/learn. The problem with my setup, as I see it, is that it doesn't run right and there's far too many variables that could be part of the problem/solution. Also, Michael's writeups are written with mass air strategies in mind, so I'm not sure how much of them even apply to speed density. Without a design-level users manual containing the theory of operation of the Ford system, I'm never going to do better than shots in the dark.

This is where I see megasquirt as a better option for me. Fueling and idle control is a matter of only a handful of variables vs dozens in the Ford EECs. There's also far better written support available for the strategy. Also, there's lots of stories out there that basically consist of "I installed megasquirt and had the car idling better in 10 minutes than I managed in 6 months of fiddling with the Ford EEC". I won't know until I try, but it sure sounds better than the complicated web that is the Ford system.
efloth
Posts: 274
Joined: 2021 Feb 15, 22:12
Location: Sacramento CA
Vehicle Information: 1991 F150 4.9L J1X 80lb Injectors E85
1995 F150 5.8L MOB1

Re: Idle stability control in A1C

Unread post by efloth »

I feel your sentiment. The learning curve is steep but I was eventually able to achieve better than stock drivability on my mild inline 6. You're obviously dealing with a different set of variables but my core issues were transient fuel and accel enrichment. I ended up setting those multipliers next to zero. I think we can figure this out before you spend more money. Send a screenshot of all the transient and accel enrichment parameters.

It's a shame that moates was shut down. I have a quarter horse and jaybird so I can use SCT chips moving forward.
Sevensecondsuv
Posts: 111
Joined: 2021 Nov 08, 22:24
Location: North Central IL
Vehicle Information: 1994 F-350 CCLB 7.5/ZF/4wd
1995 F-250 RCLB 4.9/T18/4wd
2000 Excursion 6.8/4R100/4wd
2001 Ranger RCSB 2.3/M5OD/2wd - turbocharged
2007 Town Car 4.6/4R75E
2011 Ranger SCSB 2.3/M5OD/2wd
wbo2_aem_uego

Re: Idle stability control in A1C

Unread post by Sevensecondsuv »

I started messing with the VE table. It appears that's the source of all, or at least most, of my woes. I pulled almost 40% out of the 750-1250 rpm / 60%+ cells and that got rid of the stumbling rich fall-on-its-face routine if you bogged it letting the clutch out. I then started running logs and using the histogram to tweak the VE table. It appears that works good for the "meat" of the table, but not the fringes - gotta spend enough time in a cell to get a good averaged correction factor. The other thing I found was if I made the 25/30/35% load cells as lean as the histogram called for, I got nasty trailer hitching when trying to feather in and out of the throttle. So next step is richen those up to make it drive smoother. Fingers crossed that after a few more sessions experimenting with the VE table, I'll have rid it of 95% of the weird behavior. After that I can worry about ISC parameters, transient fuel, etc. As a final step I'd like to set up open loop enrichment for WOT.
efloth
Posts: 274
Joined: 2021 Feb 15, 22:12
Location: Sacramento CA
Vehicle Information: 1991 F150 4.9L J1X 80lb Injectors E85
1995 F150 5.8L MOB1

Re: Idle stability control in A1C

Unread post by efloth »

I'm glad you're making some progress. I spent way too much time working on my VE table trying to fix issues that ended up being too much transient fuel. Remember you are working with a base tune that was set up for 19 lb injectors. You can correct it with the VE table, but I think you're better off reducing transients to zero and see if that produces the same improvement. It's at least worth the 5 minutes to rule that out.
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