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R53 Mini - Stalling once warm


noss
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Hi all, I've just recently installed a G4+ in my R53 Mini and was chasing a bit of advice on getting it running properly.

It's a low km motor that I've swapped in and at the moment everything is stock except for intake, exhaust, sprintex supercharger and 550cc EV14 injectors. I've made the change to the master fuel based on my wideband sensor, currently running a 13ms master fuel setting. I've also gone through the calibration of the APS/TPS and MAP twice just to make sure I didn't forget to push it to the ECU.

When coming to a stop after driving for a while, the motor stalls. Reading through the help files, it sounds like it could be the anti stall or proportional gain tables. Noting that the proportional gain values drop from 1.5 at 60c ECT to 0.9 at 80c ECT, is this the right place to start? As it's not really explained in the help file, what do the values actually correspond to so I can make adjustments properly? 

Also curious as to how the MAP limit works. I'm seeing a boost cut at 15.3psi (207kpa/3.93v on the MAP), referring to the MAP limit table, it was set at 215. As 207kpa is about 96% of 215kpa, are there settings elsewhere that result in a change to that limit? Just wanting to make sure I'm understanding 100% how it's working before I start adjusting..

 

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For the idle it will be best to try to capture that in a log and post it here along with your map.  https://www.youtube.com/watch?v=_P1LRANeO4A

The MAP limit has a 10KPa control range from memory (when advanced mode is turned off).  That means it will start to apply a minimum amount of cut 10Kpa before the value in your MAP limit table.  If MAP continues to climb then the ECU will progressively increase the amount of cut until it reaches the MAP limit where it will apply 100% cut.  You can turn on advanced mode if you want to adjust that control range but generally once you know how it works it is best to stick with that strategy.

FYI, all other limiters work the same way, RPM limit for instance has a default control range of 200RPM, so this means your RPM limit will start to come in 200RPM earlier than the setpoint.

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On 4/11/2018 at 11:34 AM, Narvarr said:

From reading the help files, lowering your lockout RPM should help as well.

yeh, i gave that a go before i posted up. the base map had it set at 500rpm and i reduced it to 150rpm but it didn't make any difference.

Adam pointed out over email that the correct place to be looking was the top row of the e-throttle target table. He adjusted some of the figures and I've tweaked a little bit further. The car no longer stalls 9 out of 10 times, but when it doesn't stall the engine speed drops to about 500rpm before jumping back up, so a little more tweaking of the map required but it's certainly on the right track.

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Without seeing your map+logs I cant be sure its the same problem, but i've seen a "problem" on ethrottle cars before where the rate of rpm drop is too quick for the ethrottle to "catch" the rpm's as they drop.

This is because you would typically have 0 as the target position when the pedal requests 0, but at idle rpm, you would request 2-3% throttle (via either the throttle target table or idle position). When the car was stalling this transition was quite quick - eg below 1500 rpm the 0 row was 2%, and above 1500 it was 0. What happened is that the revs had to drop below 1500 before it would start to open the throttle, and it couldnt notice the problem + open the throttle enough to catch it before stalling. The fix/workaround I ended up using was to taper this in a bit by adding a few more RPM rows between 1000 and 2000 and setting these cells to 0.5% or 1%. This makes it start opening the throttle a bit earlier when revs are dropping. This can cause a little bit of rev hang so I only targetted it at below 2000rpm where this wouldnt be an issue.

I'd like to hear if anyone has fixed this a different way, maybe with some idle control settings? I couldnt see a way to get around the fact that idle control had basically the same problem in that it didnt have long enough to fix the problem when the rpm was dropping quickly usually because of the speed lockout. Has anyone tried disabling speed lockout in ethrottle idle control so its active whenever you put the clutch in below certain rpm?

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