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Odrapnew
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A/C idle vs part throttle, IAC duty cycle

Post by Odrapnew » Sat Jul 27, 2024 1:16 pm

I've been playing around with my air conditioning idle control and running into an issue.

First off, idle is fairly solid without AC

When I turn on AC, IAC jumps up as expected, but not enough so rpm is low. IPSIBR starts at 0 and starts to increase, bringing IAC duty cycle with it. Makes sense.

So, I increasd ACPPM to increase air when AC is on and DACPPM to reduce when AC disengages. This helps with idle, but now my issue is part throttle.

The AC compressor will kick on/off as the low side pressure in the system increases and decreases. This also affects IAC duty because of ACPPM mentioned above. When I'm cruising at part throttle, this causes the car to accelerate/decelerate.

IAC DC jumps by about 20% when AC kicks on, so it accelerates and then drops by 20% when compressor disenggages and slows down. Makes part throttle cruising annoying.

Any thoughts on this?
Do I just keep ACPPM lower for drivability and let the ecu learn idle air?
Or am I missing something?
'89 Notch, 304(5.0), Novi2K@13psi (currently not installed) TFS heads, TFS Stage 1 cam, Cobra intake, 60lb'ers and Pro-M 80mm, longtubes_x-pipe_flowmasters and more crap that doesnt increase power. 437rwhp@5500(and still climbing)/438rwtq@~4000rpm Tweecer R/T w_BE and EA

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Re: A/C idle vs part throttle, IAC duty cycle

Post by cgrey8 » Mon Jul 29, 2024 7:36 am

It's been a while since I did this to my tune, but whatever numbers I came up with are still working well today. The main thing I remember about setting my tune up for AC were the values I had to use for AC Adder/Subtractor were SUBSTANTIALLY higher (like 10x higher) than the stock numbers in order to get AC engagement to not alter RPM at idle. And at the time, I wondered if the amount I was having to modify them was an indication that something else wasn't right, mechanically or in the tune. But I never found that something else so the values remain with no ill side-effects that I've noticed. Since my truck never had Cruise Control, I'm not sure that I would notice if I was increasing/decreasing speed based on compressor or just driving conditions. I'm so used to just modulating my throttle that I can't say whether I would notice this issue if it existed. So for all I know, my setup suffers this too. But if it does, it's not noticeable to me at all.
...Always Somethin'

89 Ranger Supercab, 331 w/GT40p heads, ported Explorer lower, Crane Powermax 2020 cam, FMS Explorer (GT40p) headers, aftermarket T5 'Z-Spec', GUFB, Moates QuarterHorse tuned using BE&EA

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MrsJones
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Re: A/C idle vs part throttle, IAC duty cycle

Post by MrsJones » Mon Jul 29, 2024 11:52 am

I'm gonna comment on this simply because I want to keep up with this subject as I'm about to reinstall the AC system back in my car.

I expect I will have to make similar changes to my tune in this regard.

With respect to the part about "speeding up and slowing down", if this is happening while using the cruise control, I would expect the cruise control should be controlling the speed changes.

Larry
1993 Mustang Coupe, Boss block low compression 331 cu/in, Victor Jr. heads, TFS Stage 2 cam, GT40 tubular intake, 30# injectors, 65 mm Pro-M MAF w/balance of induction stock, BBK shortys and 2 1/2 exhaust. A9L GUFB w/Moates QH, BE and EA.

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Re: A/C idle vs part throttle, IAC duty cycle

Post by Odrapnew » Mon Jul 29, 2024 12:24 pm

@cgrey8 - I currently have my adder/subtractors at about 8x stock, so at least were on similar page for those values.

In order for me to get 'perfect' IAC adder for AC at idle, I need to increase that value another 50%. Then when AC kicks on at idle, IAC opens enough to get pretty close to target rpm.

The problem is that with that value, if I'm driving with light throttle (say 30mph in 3rd gear), when the compressor turns off, the car slows down. When it kicks back on, car noticeably accelerates so it gives an annoying surge while trying to hold constant speed.

Now, if I lower the adder/subtractor a bit, I can get a more constant part throttle cruise, but idle is low...at least initially after clearing KAMS. Eventually the ECU learns the idle and it's good, but the learned value is very high. This is probably a bit better since it learns idle and cruising is more consistent, it's just that initial learning that needs to happen, rpm can be quite low until IAC adjusts.

@MrsJones - I haven't checked using cruise control. My reference to cruising is just 'cruising' along at light throttle.
'89 Notch, 304(5.0), Novi2K@13psi (currently not installed) TFS heads, TFS Stage 1 cam, Cobra intake, 60lb'ers and Pro-M 80mm, longtubes_x-pipe_flowmasters and more crap that doesnt increase power. 437rwhp@5500(and still climbing)/438rwtq@~4000rpm Tweecer R/T w_BE and EA

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Re: A/C idle vs part throttle, IAC duty cycle

Post by JuiceSC » Tue Jul 30, 2024 11:54 am

You did go through the idle learning process, and turned A/C on/off, lights on/off, blower fan hi, turn steering wheel, etc, right?

Tuner pro has both of those at .05 lb/min stock, its in RPMs in Caledit at 24 rpms.
I would say try .1 which should roughly be a 50 rpm bump in idle for A/C. I doubt you'd want them any higher than .2 lb/min. I can honestly say I never touched those setting, but my memory isn't the greatest, and I never recharged my A/C after my last engine pull out. lol

Odrapnew , I think you still have some work to do tuning idle and light throttle conditions. But it's just a guess without seeing logs.
ISCDC will be around 75% once at part throttle and should not have any effect on A/C while cruising.

Mrs Jones, your A/C should work just fine at the stock settings. Your idle fuel is dialed in. :biggrin:
91 GT, A9P, systemax II, 75mm tb, AFP, 75mm Pro M, 42#, Vortech S trim, GT40 crate 5.0, BBK catted X, flows, Tremec 3550, Pro 5.0, 3.27 gears. Tweecer RT, TunerPro.

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Re: A/C idle vs part throttle, IAC duty cycle

Post by Odrapnew » Tue Jul 30, 2024 1:19 pm

JuiceSC wrote: Tue Jul 30, 2024 11:54 am You did go through the idle learning process, and turned A/C on/off, lights on/off, blower fan hi, turn steering wheel, etc, right?

Tuner pro has both of those at .05 lb/min stock, its in RPMs in Caledit at 24 rpms.
I would say try .1 which should roughly be a 50 rpm bump in idle for A/C. I doubt you'd want them any higher than .2 lb/min. I can honestly say I never touched those setting, but my memory isn't the greatest, and I never recharged my A/C after my last engine pull out. lol

Odrapnew , I think you still have some work to do tuning idle and light throttle conditions. But it's just a guess without seeing logs.
ISCDC will be around 75% once at part throttle and should not have any effect on A/C while cruising.

Mrs Jones, your A/C should work just fine at the stock settings. Your idle fuel is dialed in. :biggrin:
I'm working on the idle tuning now. I've been using the writeup on Decipha's site to get non-AC idle dialed in and it seems pretty good. Car drives good and I can pretty much idle while in gear (TFS Stg. 1 cam, i.e. fairly mild).

Now I'm working to get the idle/driving with AC dialed in.

I'm using Binary Editor for tuning. I don't have my laptop with me today.
In BE, my understanding is ACPPM is the flow adder for when AC kicks on. DACPPM is the flow reducer when AC turns off.
Changing that value impacts how much the IAC opens to compensate for the added load by the AC.
I think the Tuner Pro 0.05lb/min aligns with the stock tune.
I currently have that value at 0.4 lb/min, yes, 8x stock, but I did that because when I would turn the AC on, the short term IAC value would increase significantly to keep rpm on target. Eventually ISCKAM3 (Neutral Idle w/ AC) would learn, but I still end up with the cruising speed IAC surge.

I'll try dropping ACPPM back down to stock and see what happens. I'm concerned that when AC kicks on, the IAC won't open enough and engine will die at idle.
'89 Notch, 304(5.0), Novi2K@13psi (currently not installed) TFS heads, TFS Stage 1 cam, Cobra intake, 60lb'ers and Pro-M 80mm, longtubes_x-pipe_flowmasters and more crap that doesnt increase power. 437rwhp@5500(and still climbing)/438rwtq@~4000rpm Tweecer R/T w_BE and EA

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Re: A/C idle vs part throttle, IAC duty cycle

Post by MrsJones » Wed Aug 21, 2024 9:47 am

I'm still messing with my initial startup stuff but have been away from it for while. I have been reinstalling all the parts to provide air conditioning to the car...... once AGAIN! Having finished that task, I'm looking at idle conditions WITH AC. I'm experiencing some rise in ECT while sitting still at idle. Curious as to what the A9L was adding, RPM wise, this morning I started the engine with KAM's cleared and let it warm up to ~160. Then turned on the AC and noticed the DSRPM rose only 16 RPM. I did this a couple of times and the log verified what I saw. Checking the DNAC, in the tune, it should have raised the RPM by 24.

I haven't dealt with this long enough to understand if I should just command more RPM in the DNAC or attack the add and subtract scalars, DACPPM and ACPPM. The log indicates that actual RPM dropped from 848 DSRPM to ~804, even tho DNAC commanded an additional 24. That was what happened during the first time I turned the AC on which was only for about 3 sec, long enough see the change in the RPM and DSRPM. I also noted that KAMRF returned to 1.000 where it had been in the 1.025 range at idle. The second time was for about 6 seconds. During that time frame, the RPM's acted the same but I did notice that about half way through this cycle, KAMFR, which once again went to 1.000, was starting to learn (I suppose) and raised itself to 1.004. Is this part of the learning process for AC idle control?

Any thoughts......
1993 Mustang Coupe, Boss block low compression 331 cu/in, Victor Jr. heads, TFS Stage 2 cam, GT40 tubular intake, 30# injectors, 65 mm Pro-M MAF w/balance of induction stock, BBK shortys and 2 1/2 exhaust. A9L GUFB w/Moates QH, BE and EA.

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Re: A/C idle vs part throttle, IAC duty cycle

Post by Odrapnew » Wed Aug 21, 2024 1:01 pm

Sounds like you need to do some tweaking to ACPPM and DACPPM.

Log IPSIBR, ISCKAM2 (neutral no AC) and ISCKAM3 (neutral with AC).
Let the car idle without AC until IPSIBR is 0 and ISCKAM2 stops updating.
Then, turn on AC and let it idle until IPSIBR is 0 and ISCKAM3 stops updating.

Early on, what I found is when I would turn on the AC, my rpm would drop, ISPIBR would increase (pulling ISC DC up with it) and eventually ISCKAM3 would update as it learned.

Once IPSIBR was 0 and ISCKAM3 settled, I increased ACPPM by the ISCKAM3 value. I also increased DACPPM by the same value.

After clearing KAMs and trying the updated calibration, when I turned AC on, my ISC value jumped up, and IPSIBR and ISCKAM3 stayed fairly close to 0. My DSRPM value increases by the AC RPM adder I have set (which I think is 50rpm). Not sure why your DSRPM did not increase the same as the adder, but there might be something else contributing (I'm not sure what though).

I'm still dealing with a bit of a surging issue at light throttle.
At idle, if I turn AC on/off, it idles just as expected.

If I'm under light cruising speed, say 20mph in 2nd gear, when the AC compressor kicks on/off I get a surge/slowdown. It speeds up when compressor kicks on and slows down when it turns off. My IAC DC jumps up when the compressor kicks on and down when it turns off, which is normal, but it seems like when I'm driving it adds/subtracts too much air causing the surge. It's almost like the IAC transfer curve is not correct, but it's stock.
'89 Notch, 304(5.0), Novi2K@13psi (currently not installed) TFS heads, TFS Stage 1 cam, Cobra intake, 60lb'ers and Pro-M 80mm, longtubes_x-pipe_flowmasters and more crap that doesnt increase power. 437rwhp@5500(and still climbing)/438rwtq@~4000rpm Tweecer R/T w_BE and EA

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Re: A/C idle vs part throttle, IAC duty cycle

Post by JuiceSC » Wed Aug 21, 2024 1:39 pm

Mrs Jones, all that sounds right. Why dsdrpm only rose by 16 vs 24, I couldnt tell ya, its "eec magic" lol. I would simply double the ac adder to 48 to compensate for the lower idle torque of a cammed engine. And call it done.
IATs will rise at idle, again, I think you are fine as-is.
91 GT, A9P, systemax II, 75mm tb, AFP, 75mm Pro M, 42#, Vortech S trim, GT40 crate 5.0, BBK catted X, flows, Tremec 3550, Pro 5.0, 3.27 gears. Tweecer RT, TunerPro.

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Re: A/C idle vs part throttle, IAC duty cycle

Post by MrsJones » Wed Aug 21, 2024 3:39 pm

JuiceSC,

I'll give your suggestion a shot. I was thinking along the same line.

Thanks,

Larry
1993 Mustang Coupe, Boss block low compression 331 cu/in, Victor Jr. heads, TFS Stage 2 cam, GT40 tubular intake, 30# injectors, 65 mm Pro-M MAF w/balance of induction stock, BBK shortys and 2 1/2 exhaust. A9L GUFB w/Moates QH, BE and EA.

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Re: A/C idle vs part throttle, IAC duty cycle

Post by Odrapnew » Wed Aug 21, 2024 8:18 pm

Raising the rpm adder doesn't resolve the real issue.

You said when you turned the AC on, DSRPM increased by 16rpm (instead of 24rpm) but actual rpm dropped by about 50rpm.

If you bump the AC adder to 48rpm, DSRPM may now increase by 32rpm, but your actual rpm will still be below DSRPM because IAC is not adding enough air. If you idle long enough with AC on, actual rpm will increase to closely match DSRPM as short term (IPSIBR) and long term(ISCKAM3) air trims update.

Log IPSIBR, ISCKAM2 and ISCKAM3 to see what they are doing.
'89 Notch, 304(5.0), Novi2K@13psi (currently not installed) TFS heads, TFS Stage 1 cam, Cobra intake, 60lb'ers and Pro-M 80mm, longtubes_x-pipe_flowmasters and more crap that doesnt increase power. 437rwhp@5500(and still climbing)/438rwtq@~4000rpm Tweecer R/T w_BE and EA

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Re: A/C idle vs part throttle, IAC duty cycle

Post by MrsJones » Thu Aug 22, 2024 4:51 pm

I made the effort to log some AC time at idle today. Comments and suggestions are welcomed.

What you will find in the pic is a portion of the log where I turned the AC on and allowed ECT to climb to 200 deg then turned it off. I turned off some of the pens to make the items of interest stand out better. When I started the engine, it was at 152 deg and allowed it to get through the OL portion and the funny little rise at 172 deg where it return to commanded idle of 848 RPM before turning the AC on. I have some cooling issues at the moment I'm working out and should be under control this coming weekend. Just follow the ISCDTY line for the on and off indications. ISCKAM2 is flatlined across the top at 0.079. IPSIBR is up there with it, peaking at 0.1804. ISKAM3 worked itself up to 0.0478 and flatlined. Engine RPM stayed pretty close to DSDRPM. DSDRPM climbed to 992 during all this and I assume some of this was due to ECT. When I turned the AC on, ISCDTY was at 36 and peaked at 59.6 @ 992 RPM, @ 200 ECT. When I turned the AC off KAMRF had peaked at 1.039. I may add here that I cleared KAMRF prior to starting.

I tried adding additional RPM to DNAC, changing it from 24 to 48. This time, DSDRPM responded accordingly as did N (engine RPM).

BTW, my cooling issues are only at idle with AC on. I believe the fan clutch is not up to the task. When driving, the normal is 188-190 deg with ~40 deg differential from abiante outside. All this aside, the point of interest was, what happens when I run the AC at idle.

Also, I'm including the .BIN and the log for those who would like to review them.
AC_OnResults.jpg
AC_OnResults.jpg (74.05 KiB) Viewed 11338 times
Changes_1c 2024_Aug_22_11-10-41.7z
(470.45 KiB) Downloaded 65 times
Changes_1c.7z
(22.66 KiB) Downloaded 76 times
Thanks to all,

Larry
1993 Mustang Coupe, Boss block low compression 331 cu/in, Victor Jr. heads, TFS Stage 2 cam, GT40 tubular intake, 30# injectors, 65 mm Pro-M MAF w/balance of induction stock, BBK shortys and 2 1/2 exhaust. A9L GUFB w/Moates QH, BE and EA.

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Re: A/C idle vs part throttle, IAC duty cycle

Post by Odrapnew » Thu Aug 22, 2024 6:47 pm

OK, I went through similar issues.
What you should do is get idle air squared away with AC OFF.
Read up on decipha Idle Air writeup http://www.efidynotuning.com/

The main goal is to get ISPIBR, ISCKAM2 and ISCKAM3 to be close to 0 all the time. They will fluctuate a little, but shouldn't be much.

ISCKAM2 of 0.079 means that your idle air is close, but not quite dialed in. The ECU learned that it needs to add 0.079lb/min of air to hit target rpm (AC off) vs. what's in the tune. A few things could be off, but one thing you can do is subtract that value from ITHBMA as a start. Basically telling the ECU that your throttle body is flowing less air so it will add more air via the IAC duty cycle.

When you turn on the AC, since your rpm (N) is below DSDRPM, IPSIBR increases.
IPSIBR peaking at 0.1804 plus ISKAM3 at 0.0478 means the ECU is adding 0.2282lb/min of air vs. what your tune is tell it when the AC is ON. ACPPM and DACPPM are air flow adder/reducer for when AC kicks on/off, which is what you would update.

Correcting AC OFF first will help get A/C ON closer, so the 0.2282 value will likely decrease.

The RPM increasing over time could be the rpm adder vs. temp (FN825A) and/or it could be rpm adder vs. time (FN880).
Those 2 were driving me nuts as I couldn't figure out why DSDRPM kept increasing.
'89 Notch, 304(5.0), Novi2K@13psi (currently not installed) TFS heads, TFS Stage 1 cam, Cobra intake, 60lb'ers and Pro-M 80mm, longtubes_x-pipe_flowmasters and more crap that doesnt increase power. 437rwhp@5500(and still climbing)/438rwtq@~4000rpm Tweecer R/T w_BE and EA

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Re: A/C idle vs part throttle, IAC duty cycle

Post by MrsJones » Fri Aug 23, 2024 7:57 am

Odrapnew,

Thank you for your comments and pointers. I will try some of this today.

One comment really puzzled me.
Correcting AC OFF first will help get A/C ON closer, so the 0.2282 value will likely decrease.
Where did you come up with this number? I'm lost!

EDIT: Never mind... I just didn't read it close enough. Since I'm here, am I to assume that ISCKAM3 is an air adder like IPSIBR? I have been thinking that ISCKAM3 was a fuel adder. My bad!

Thanks for your input,

Larry (the dummy)
1993 Mustang Coupe, Boss block low compression 331 cu/in, Victor Jr. heads, TFS Stage 2 cam, GT40 tubular intake, 30# injectors, 65 mm Pro-M MAF w/balance of induction stock, BBK shortys and 2 1/2 exhaust. A9L GUFB w/Moates QH, BE and EA.

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Re: A/C idle vs part throttle, IAC duty cycle

Post by MrsJones » Sat Aug 24, 2024 9:46 am

The pic below shows some results after making a single change to ITHBMA where I subtracted 0.05 from the previous setting. This will reflect the differences this change made to my combo, which really surprised me. This pic can be compared to the previous pic above. Sorry about the locations of each pen, in relationship to the other pic, as this is the way BE decided to display them. I should also mention that I cleared Kams prior to starting the engine.

I have parked the cursor where IPSIBR and ISCKAM3 seem to intersect so you can see the actual numbers in the tree. Once again, ISCDTY reflects when the AC was turned on and off. The huge difference in IPSIBR and ISCKAM2 really surprised me. However, it seems like ISCKAM3 picked up the slack as that number almost doubled, very near the amount I changed ITHBMA. I suppose this is where the adder/subtractor scalers come into play. Advice here would certainly be appreciated.

Another thing I wish to draw attention to is the way ISCKAM2 and ISCKAM3 both just dropped of the chart (went to 0.00) after a short period with IPSIBR reporting -0.1147 at the same point. This was ~20 sec after I turned the AC off.

AC_OnResults2.jpg
AC_OnResults2.jpg (77.9 KiB) Viewed 11260 times

Not sure what else to add here so if there are any questions, please feel free to ask. Also, as usual, all comments/suggestions are very welcomed.

Thanks for your time,

Larry
1993 Mustang Coupe, Boss block low compression 331 cu/in, Victor Jr. heads, TFS Stage 2 cam, GT40 tubular intake, 30# injectors, 65 mm Pro-M MAF w/balance of induction stock, BBK shortys and 2 1/2 exhaust. A9L GUFB w/Moates QH, BE and EA.

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Re: A/C idle vs part throttle, IAC duty cycle

Post by Odrapnew » Sat Aug 24, 2024 1:37 pm

@MrsJones Sorry for not responding to your previous post. I saw it but forgot about it.

Anyway, the 0.2282 that I mentioned is the sum of IPSIBR (0.1804) and ISKAM3 (0.0478).
That was the total air the ECU was adding to hit the target rpm. I'm not sure why ISCKAM3 stopped learning in your previous log. I've run into that before as well and haven't figured out why it does that sometimes.

With your latest datalog/tune, when you subtracted 0.05lb/min from ITHBMA you're telling the ECU that the throttle body is flowing less air. In turn, the ECU will calculate that it needs to add more air through the IAC. You're moving in the right direction.

Looking at ISCKAM2 in your latest image, its at 0.016 just before you turned on the AC and it looks like IPSIBR was about 0. That's pretty dialed in. You could subtract 0.016 from ITHBMA and that should bring ISCKAM2 to almost 0.

With your latest log with AC ON, notice how IPSIBR was high and then worked its way down to zero and how ISCKAM3 worked it's way to 0.112. That's the ECU learning what air is needed. If you understand how fuel adaptive learning works, it's very similar.

If you increase ACPPM and DACPPM both by 0.112, that should get both IPSIBR and ISCKAM3 to be very close to 0 with AC on.

As for why ISCKAM2 and 3 dropped to 0, I have no explanation for that one.

BTW, what are your current values for ACPPM and DACPPM? Those are the air adder/subtractor for when the AC turns on/off
'89 Notch, 304(5.0), Novi2K@13psi (currently not installed) TFS heads, TFS Stage 1 cam, Cobra intake, 60lb'ers and Pro-M 80mm, longtubes_x-pipe_flowmasters and more crap that doesnt increase power. 437rwhp@5500(and still climbing)/438rwtq@~4000rpm Tweecer R/T w_BE and EA

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Re: A/C idle vs part throttle, IAC duty cycle

Post by MrsJones » Sun Aug 25, 2024 4:27 pm

Ordrapnew,

Thanks for your help!

The DACPPM and ACPPM are both set at 0.0498 lb/min which appears to be a stock calibration. I will try your suggestion and see how it works out.

BTW, in another log I noticed, while on cruise control, the additional load from the AC has a smoothing effect, meaning that TP is not doing as much "on and off" work (adjustment to maintain speed). I can't tell that the engine is changing enough, even with simple foot operation, when it cycles. That probably doesn't make much sense so I'll stop right there.

This AC addition is trying my patience as far as keeping the engine cool. I'm trying to make the mechanical fan do the job, like factory original, but having an issue with heat at idle. That's why you haven't seen any data reflecting activity in the upper ECT range. Hot idle but cools down with movement. Don't want to go electric but will if there is no alternative. Done it before, on this car, in 2005, with a SN95 GT fan, and controlled it with this same ECU. I'd just rather not again.

Thanks again for your assistance,

Larry
1993 Mustang Coupe, Boss block low compression 331 cu/in, Victor Jr. heads, TFS Stage 2 cam, GT40 tubular intake, 30# injectors, 65 mm Pro-M MAF w/balance of induction stock, BBK shortys and 2 1/2 exhaust. A9L GUFB w/Moates QH, BE and EA.

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Re: A/C idle vs part throttle, IAC duty cycle

Post by Odrapnew » Wed Aug 28, 2024 1:27 pm

Glad it's starting to work out for you.

I've dealt with drivability/idle issues for as long as I can remember and just this year I've really started to dial it in and made huge progress.

Regarding cooling, I've had electric fans on my car for almost as long as I've owned it (since 2003) and have always had them on a manual switch. This year I finally made the jump to ECU controlled fans and it's another big jump in drivability. Not so much making it easier to drive, just one thing I don't need to remember to turn on. If I'm in 90F+ temps, lots of traffic with AC blasting, my temps get up to 220F+, but if I turn off the AC for a few minutes the temp drops fairly quick.

I don't see what car you have, but like you said, maybe the mechanical clutch is going bad and just needs to be replaced.
'89 Notch, 304(5.0), Novi2K@13psi (currently not installed) TFS heads, TFS Stage 1 cam, Cobra intake, 60lb'ers and Pro-M 80mm, longtubes_x-pipe_flowmasters and more crap that doesnt increase power. 437rwhp@5500(and still climbing)/438rwtq@~4000rpm Tweecer R/T w_BE and EA

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Re: A/C idle vs part throttle, IAC duty cycle

Post by MrsJones » Sat Aug 31, 2024 10:52 am

Since the AC install, I'm having an issue with KAMRF adding fuel at idle to the tune of 4% at times. I haven't spent any time trying to correct this issue due to the overheating AND the fact my WB took a crap... AGAIN! These problems are a fix in progress!

I replaced the fan clutch with a Hayden #2733 but there was no benefit gained. However, I've never heard a fan clutch cycle like this thing does so the switch was a good thing. Highly recommend! Installed a new SVE 3 row radiator but that was, once again, NOT beneficial. The 19 year old Ford Motorsport rad was doing just fine. Yesterday, I changed the thermostat from a 195 to 180. Some gain in temp control here but still can't sit and idle long with AC running. This brings me to the water pump! All indications (receipts) tell me that the correct pump is installed but 14 years ago. It's next on the agenda.....

In 2005, I had a SN95 fan on this car and had no problem letting it sit with the AC on. Matter of fact, on jack stands, in the garage in Florida, the AC would cycle with 38 degree air coming out the ducts without overheating. I'm considering redoing this setup if a new pump doesn't correct the heating issue.
If I'm in 90F+ temps, lots of traffic with AC blasting, my temps get up to 220F+, but if I turn off the AC for a few minutes the temp drops fairly quick.
This is the same problem I'm having but NOT being able to bring the temps back down with the current configuration. Even revving the engine, without AC, will only drop the temp a few deg. Moving is the only cure! In test mode, a couple of days ago, I logged an ECT climb to 240 just to see if the cooling sys would cool it back down after turning off the AC. 206 was as low as I could get it. This may be an acceptable temp for most but not for me. Anything in the 190's I'm happy.

What ECU are you using? What pin to control the fan off/on with? My notes direct me to pin 41 on my A9L, the same A9L as in Florida. I'm really trying to make it work without doing this but will if nothing else produces the results I'm looking for.

Check my sig for car details.

Thanks,

Larry
1993 Mustang Coupe, Boss block low compression 331 cu/in, Victor Jr. heads, TFS Stage 2 cam, GT40 tubular intake, 30# injectors, 65 mm Pro-M MAF w/balance of induction stock, BBK shortys and 2 1/2 exhaust. A9L GUFB w/Moates QH, BE and EA.

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Re: A/C idle vs part throttle, IAC duty cycle

Post by Odrapnew » Sat Aug 31, 2024 11:36 am

My understanding is that overheating at idle and ok at highway is usually a fan issue. Since you stated the SN95 fan kept it cool, that backs up that statement.

You have a shroud around the fan, correct?

I have a Summit aluminum radiator with old school Ramcharger dual fans. It does fine most of time, but idling with AC on in 90+ degree weather is about it's limit. I've never gotten above 225, but fans run on high constantly.

I have my fans connected to pin 41. Mine is an A9S, but that just a few different calibration settings vs A9L, all pins are the same.

Since these are dual speed fans, I have the high speed connected to pin 41 and controlled via coolant temp (on at 214, off at 208) and I have the low speed connected to AC so whenever AC is selected on the dash, fans are on low.

I also have a 3 position switch. High, Auto, and Off. 90% of time is Autoz, Off is mainly if I'm driving highway with AC on and don't need the fans on.

I did the ECU/AC fan control this spring. Before that it was all manual control and a few times I forgot to turn them on and go quite hot, but never overheated.

If I were you, I'd look into the Contour fans. I've heard they are a 'beast' for cooling. I have the ramchargers because they were the slimmest fans of the time. I have less than 1/4" gap between fans and my 10rib crank pulley.
'89 Notch, 304(5.0), Novi2K@13psi (currently not installed) TFS heads, TFS Stage 1 cam, Cobra intake, 60lb'ers and Pro-M 80mm, longtubes_x-pipe_flowmasters and more crap that doesnt increase power. 437rwhp@5500(and still climbing)/438rwtq@~4000rpm Tweecer R/T w_BE and EA

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Re: A/C idle vs part throttle, IAC duty cycle

Post by Odrapnew » Tue Sep 03, 2024 12:33 pm

An update my side of this thread, I made some headway.

In short, the IAC transfer function was not accurate (my own fault)

Last year I was chasing issues and one was actually related to idling.
I bought a new IAC and did some 'musical components' by swapping the actual valve from the new one to my OE solenoid.
What I noticed was the spring in the OE valve was softer than the new valve. I thought the old valve was sticking open.
Well, the new valve required higher duty cycle in the mid range(40-60%) to hit desired flow.
So cold starts and with AC, I had to command higher duty cycle to hit the right flow.
Low and high duty cycles seemed to be good, just the middle was bad.

I swapped the OE valve to the OE solenoid and put that back on the car.
I noticed as soon as I started the car, ISPIBR was negative and continued to go more negative with cold start.
That meant my startup air table needed to be reduced. This also occurred with warm and hot engine because at start, those also command that mid-range duty cycle.

After car got up to temp, it was fairly close at stable idle.

When I turned on the AC for the first time, RPM jumped way up and so ISPIBR started to go negative again.
Eventually ISCKAM3 updated and stabilized. My DACPPM and ACPPM both about double what they needed to be with the old IAC.
I made that adjustment and now IPSIBR, ISCKAM2 and 3 are all fairly close to 0 at hot idle. Small tweaks left, but much better.
In addition, when I'm driving along, I can barely feel the AC compressor kick on/off unlike before it would surge.

So, all those words to say the IAC combo I had was not correct.
'89 Notch, 304(5.0), Novi2K@13psi (currently not installed) TFS heads, TFS Stage 1 cam, Cobra intake, 60lb'ers and Pro-M 80mm, longtubes_x-pipe_flowmasters and more crap that doesnt increase power. 437rwhp@5500(and still climbing)/438rwtq@~4000rpm Tweecer R/T w_BE and EA

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Re: A/C idle vs part throttle, IAC duty cycle

Post by Odrapnew » Tue Sep 10, 2024 1:47 pm

So, one final(?) update from me.
I've been playing with the IAC settings in my tune and all previous issues are resolved with the OE IAC reinstalled.
When AC is on and/or cycling, I cannot feel when it kicks on or off, perfectly smooth.

My IPSIBR and IACKAM2 and 3 are all right around 0 most of the time.

I've had to reduce my startup air flow multiplier table by a lot. I've got cold/warm starts pretty close to perfect.
I still need to work on reducing the hot start part of the table, but it's getting much better.
It's only from start to 30 seconds that needs adjustment. After the 30 seconds, it's pretty stable.
Sorry, I can't remember the FN number of that table off the top of my head.
'89 Notch, 304(5.0), Novi2K@13psi (currently not installed) TFS heads, TFS Stage 1 cam, Cobra intake, 60lb'ers and Pro-M 80mm, longtubes_x-pipe_flowmasters and more crap that doesnt increase power. 437rwhp@5500(and still climbing)/438rwtq@~4000rpm Tweecer R/T w_BE and EA

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Re: A/C idle vs part throttle, IAC duty cycle

Post by MrsJones » Sat Oct 12, 2024 10:50 am

I wanted to let those involved with this thread know that I've had, what seems to be, a never ending problem with the overheating issue. Consequently, I haven't been back to this for a while.

I replaced the entire cooling system (rad, fan clutch, water pump and thermostat) and the stat was the only thing that showed ANY CHANGE. That simply lowered the normal operating temp from 188 to 180, give or take a few deg. At a sitting still idle, the engine would still overheat with AC on. Grab a gear and go down the road, it would cool down. I finally accepted that air movement was the issue and set up an electric fan on my older Motorsports rad and reinstalled it. I chose a SN95 GT 9 blade fan and designed a relay network to control the two speeds and to bypass to high speed when the AC is on.

On initial test of the fan control system the fan did not run with AC on! I was also trying to make sure the rad was full of water as it warmed up and trying figure out WHY the fan didn't come on. Too late! Too much head pressure and the condenser exploded where the hose tubes enter the condenser, blowed them right out of the manifold. I am reconditioning another OEM condenser, right now, and will have to replace the damaged unit and recharge the system before proceeding.

My mistake/fault as the control system requires a 12 volt, ignition on, source, which I was sure (assumed) I had connected to. Memory isn't what it used to be! I corrected the problem and the fan control system does work as designed..... NOW! However, the temp switch, which controls the low or high speed fan, does not function at the temperatures as advertised. It works, but about 15 degrees higher than expected. So I'm also dealing with that and replacement is on order.

It will be a couple more weeks before I can get back into the tuning issues revolving around AC use.

I thought I would let those interested know that I haven't died or left the country, just sidetracked. I'm old, not dead!

Thanks,

Larry
1993 Mustang Coupe, Boss block low compression 331 cu/in, Victor Jr. heads, TFS Stage 2 cam, GT40 tubular intake, 30# injectors, 65 mm Pro-M MAF w/balance of induction stock, BBK shortys and 2 1/2 exhaust. A9L GUFB w/Moates QH, BE and EA.

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Re: A/C idle vs part throttle, IAC duty cycle

Post by Odrapnew » Sat Oct 12, 2024 12:46 pm

Dang, that sucks.

This spring I set my cooling fans to be controlled by the ECU (Pin 41 mod). That only controls the high speed fan for coolant temp.

I rigged a 2nd trigger to turn the fans on low anytime the AC is on. This isn't ideal because even driving down the highway, the low speed fans are on, but I set up a switch that I can turn them off if I plan to do long drive on the highway with AC on.

I want to redo it a little bit because that switch disconnects all fan control, so if i forget to turn the switch back on, the ECU will not trigger the fans. I want to set the switch to only turn off the AC, but still all coolant temp control if I forget to turn it back on. Simple enough to fix, just need to find time to figure out the wiring changes.

There is a way to have ECU control fans with AC, but it requires a transistor, which I don't think I want to tackle.
Last edited by Odrapnew on Mon Oct 14, 2024 9:48 am, edited 1 time in total.
'89 Notch, 304(5.0), Novi2K@13psi (currently not installed) TFS heads, TFS Stage 1 cam, Cobra intake, 60lb'ers and Pro-M 80mm, longtubes_x-pipe_flowmasters and more crap that doesnt increase power. 437rwhp@5500(and still climbing)/438rwtq@~4000rpm Tweecer R/T w_BE and EA

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MrsJones
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Re: A/C idle vs part throttle, IAC duty cycle

Post by MrsJones » Sun Oct 13, 2024 11:25 am

Odrapnew, "transistor"... first, as I have come to understand, Pin 55 is the location for a connection for the transistor. However, as I understand the situation, there needs to be support hardware on the ECU board to support the connection to Pin 55. I would have done this also but haven't taken the time to remove my ECU and check the board, or even tested Pin 55 for logic state (off or on). Anyway, there is a HUGE thread on this subject on this site at another location within. Search the subject and you'll find a lot more information, to confuse you even further.... he he!

I have also used Pin 41 in the past but didn't have AC to contend with at that time.

Good luck,

Larry
1993 Mustang Coupe, Boss block low compression 331 cu/in, Victor Jr. heads, TFS Stage 2 cam, GT40 tubular intake, 30# injectors, 65 mm Pro-M MAF w/balance of induction stock, BBK shortys and 2 1/2 exhaust. A9L GUFB w/Moates QH, BE and EA.

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Re: A/C idle vs part throttle, IAC duty cycle

Post by Odrapnew » Mon Oct 14, 2024 9:58 am

Woops, thanks for catching that, I corrected the post.

I have read a few threads on the Pin 55 conversion and I'm not confident I could correctly make that mod without screwing something up. I'm fine with how I have it set up for now, not perfect, but works a hell of a lot better than a manual switch to turn fans on/off.
'89 Notch, 304(5.0), Novi2K@13psi (currently not installed) TFS heads, TFS Stage 1 cam, Cobra intake, 60lb'ers and Pro-M 80mm, longtubes_x-pipe_flowmasters and more crap that doesnt increase power. 437rwhp@5500(and still climbing)/438rwtq@~4000rpm Tweecer R/T w_BE and EA

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Re: A/C idle vs part throttle, IAC duty cycle

Post by MrsJones » Sat Oct 26, 2024 11:13 am

I REALLY want to get back into the subject that this thread was started for but I having trouble with the "can't win for loosing" phrase! A few days ago, installed another condenser, started the recharge process by adding about half of a can of oil to the system first, not knowing how much I lost when the other condenser exploded. There was just enough pressure in the can to cause the compressor to cycle off and on several, more like 8 or 10, times before I could get a can of freon on the hose and in the system.

I have my high speed fan configured to come on when the compressor cycles on. As you can guess, while the compressor was cycling on and off, so was the fan. I finally got enough freon in the system to stabilize everything and proceeded to finish the charge successfully. Air coming out of the duct, on max air and medium hi fan, was showing 36 deg. All seemed perfect! I turned the engine off and removed hoses and cleaned up after myself.

With that chore done I decided to turn the car around in the driveway. As I tried to start the engine, it was quickly shown to me that the battery was near DEAD! When it finally started, I quickly realized that the alternator wasn't working. Apparently, the hits from the compressor and the high speed fan overheated the regulator and, after local testing yesterday, the rectifier bridge also. This is a Powermaster alternator and I don't know how old it is. Even being a Powermaster I'm not sure it could handle some 50-60 amp load hits like that without overheating something.

I purchased a used 3G from a local scraper and all is well for now. I plan to return the alt to Powermaster for repair so the current alt is temporary. Needless to say, I'm being very conservative with loads until it proves itself to me.

So, once again, I learned something! If I should have to recharge the AC again, I will unplug the fan circuit until the compressor is happy enough to run constantly, THEN turn the fan on. So far, everything seems to be operating as designed and the temp alt is carrying the load.

I'm doing some logging to check parameters and trying to get back in the swing of tuning. JuiceSC, I will be calling on you for some advice very soon as I have dug out the "SanityCheckFinal" tune and working with that currently. The scalers referenced in this thread will be applied soon and we'll be back in business.

Another day, another lesson.

Larry
1993 Mustang Coupe, Boss block low compression 331 cu/in, Victor Jr. heads, TFS Stage 2 cam, GT40 tubular intake, 30# injectors, 65 mm Pro-M MAF w/balance of induction stock, BBK shortys and 2 1/2 exhaust. A9L GUFB w/Moates QH, BE and EA.

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