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View Full Version : smoothing out the return to idle


BabyBlue240
02-06-2008, 01:51 AM
No matter if I turn on closed-loop PWM idle or just do the warmup option with the duty table, it's never quite smooth coming back to idle after I've been on the gas. Right when you left off the gas (and push in the clutch), the RPMs drop down to about 500-600 and then recovers back up to either the target idle speed or the preset duty of the idle valve. Once in a blue moon, it'll completely stall out right then. is there some duty cycle that the idle valve defaults to before actually entering "idle"? what's the reasoning behind this problem?

I was driving my friend's Civic and I noticed that when you push in the clutch and let the motor come back down to idle, it immediatley drops to about 1100 or 1200 and then slowly comes down the rest of the way to about 800 over a period of maybe 2 or 3 seconds. I'd like for the system to work like that. Any way of doing this? I'm running MS2 Extra Beta 2.0, but idle stuff is very similar to Msns-e for all you guys.

fryea
02-06-2008, 04:52 AM
i found my return to idle is nicer if i add an extra rpm bin below my idle in the spark table with higher than average spark values. That way if it ever dips down there the extra advance pushes it back into good idle territory, although when i got the rest of my fuel and spark tables figured out i no longer needed this.

500dollar744ti
02-06-2008, 08:19 AM
are you using the 2 wire or 3 wire valve? my idle settings are dead on like LH was, there are some good base settings on here to start from if you need them.

BabyBlue240
02-06-2008, 07:39 PM
i found my return to idle is nicer if i add an extra rpm bin below my idle in the spark table with higher than average spark values. That way if it ever dips down there the extra advance pushes it back into good idle territory, although when i got the rest of my fuel and spark tables figured out i no longer needed this.

Yeah, I did the same thing. I think that's the only reason the motor doesn't die every time.

are you using the 2 wire or 3 wire valve? my idle settings are dead on like LH was, there are some good base settings on here to start from if you need them.

2 wire Bosch. So no one knows what's going on when it's defaulting to 500 or 600 RPM? The TPS threshold is all that triggers the valve on and off, right? because in that case, I don't see how I'm having this problem while not in closed loop. The throttle should come off and the valve should go straight to the preset duty cycle from the table. Therefore, it'd just come right down to the idle speed, right? not below it and then come back up. Now in closed loop, that could just be that I don't have all the parameters right yet. But in warmup mode, it should work fine.