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Old 05-03-2015, 03:06 PM   #1
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Default MS3 idle droop help

Hey guys,

When I got my MS3x last year and installed my turbo kit, I would get an occasional stall when the a/c would engage. They didn't occur too frequently and the car would otherwise idle and drive beautifully, so I essentially left it alone. I was daily driving the car at the time.

Fast forward two motor builds, and a haphazard "pro" tune performed by a local shop, now having issues idling without a/c being on.

I am having problems returning to idle after a blip, staying in CL idle when blower motor+headlights are engaged and the subsequent stalling that occurs once the car falls off of the ramp up out of CL idle. The car will also stall when sitting at a light and the fan (FM stage 2 Spal) engages.

Hope that made sense. I have attached an .msq and log of engaging and disengaging lights+blower motor. So far I have adjusted idle ve settings, adjusted throttle screw to ~100rpm under target with idle valve at 0%, recalibrated TPS to no avail.

Any ideas? I apologize if this is a stupid question, I spent the past few weeks researching this but can't seem to get anywhere. Really frustrated as I miss dailying the car but having to balance three pedals with two feet/stopping the car with the handbrake in order to keep revs up to avoid stalling is getting really old.

Specs:
94, MS3x, GT2560r, FM/begi supporting parts, ID1000s, Supertech 8.6 84mm/Manley/ACL/ARP/BE pump
Attached Files
File Type: msl fan stall 0503.msl (342.2 KB, 38 views)
File Type: msq CurrentTune.msq (224.6 KB, 39 views)

Last edited by cmalouf; 05-03-2015 at 03:28 PM.
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Old 05-03-2015, 06:00 PM   #2
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It seems like it is stalling before megasquirt understands you turned a/c on, which I find strange. The closed-loop target never increases the 300 you've specified.

I would increase the idle delay Idle-up delay to 350-450, and then see if you can see the closed-loop target in your log change if the car still stalls. If it does and the car still stalls, start increasing the a/c Idle-up duty.

EDIT: My guess for the rest of the blips would be to fine-tune your closed-loop initial value table.

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MS3 idle droop help-weghmx7.png  
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Old 05-03-2015, 06:05 PM   #3
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Thanks for the reply!

I should have specified that my car does not have working a/c at the moment (shop that installed my motor undid the a/c compressor lines for some reason, not sure why as I swapped the first motor into the car by just moving the compressor out of the way).

The log was actually just using the blower motor (no a/c) and headlights, nothing else. When the dips are shown in the logs is where I simultaneously turned on the headlights and the blower motor for a few seconds.

Are there similar settings I should be looking for in the idle settings menu, as these controls rely solely on the CL PID control (no i/o idleup etc. assistance).
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Old 05-03-2015, 06:22 PM   #4
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Quote:
Originally Posted by cmalouf View Post
Thanks for the reply!

I should have specified that my car does not have working a/c at the moment (shop that installed my motor undid the a/c compressor lines for some reason, not sure why as I swapped the first motor into the car by just moving the compressor out of the way).

The log was actually just using the blower motor (no a/c) and headlights, nothing else. When the dips are shown in the logs is where I simultaneously turned on the headlights and the blower motor for a few seconds.

Are there similar settings I should be looking for in the idle settings menu, as these controls rely solely on the CL PID control (no i/o idleup etc. assistance).
Sorry, skimmed that and made assumptions. Haven't slept much lately. The stalling I wouldn't have much advice for then. It seems to make a nose-dive to stalling that the increasing idle-valve numbers don't even cause it to waver. Hopefully someone else has a better suggestion.
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Old 05-05-2015, 12:38 PM   #5
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Took a log of the fan stalling the car.

Is it the extreme voltage drop from this fan that's causing my issue? Has anybody ever run a PWM fan controller with a 'soft start' feature with these fans? A company called Derale makes a unit around $150 that does this, but includes a lot of temperature-sensitive programming that would be redundant when using the MS3. Seems like a bit of a bandaid but if it fixes the problem then great.
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File Type: msl fan too.msl (217.8 KB, 76 views)
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Old 05-05-2015, 05:58 PM   #6
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your battery voltage plummets, and then your VE% plummets. I'd say youre going lean as hell but your wbo2 is cutting out and reporting false data once the voltage drops so low (its reporting 13.5AFR when the car is off).

I think your deadtime at 1.070 is too low for ID1000cc injectors. you should be running 1.215 if your voltage curve has 13.5v at 100% correction.


but really that voltage drop it's whats killing you. the a/c causing a lot of drain, but even with my shitty 1.6L alternator that barely worked, it was nothing like that. But it would slowly drain voltage over time if I'd sit idle with the a/c running.
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