#1771, "Smoothed out the idle a bit wth the MS..."
Had a little time today to play around with the RS and the megasquirt, since the idle has always been a bit choppy, esp when running closed loop off of the wideband..I use the AEM UEGO wideband sensor for closed loop, and i had it mounted in the testpipe...always seem to lag in response to the MS, so today i moved the wideband sensor to approx the stock location, and idle response from the wideband was much faster. It idled smoother with less back and forth movements of the idle injector pulsewidth. Also, i've noticed that when running spark control with the MS, and you want to run 14.0 and/or around stoich(14.7:1), the leaner mix at idle wants less timing for it to idle smoother. I am at 7 degrees BTD now around 900-1000 rpm at idle, and its good. I used to run around 15 degrees at idle, but it surges a lot with that much timing with around stoich A/F mix. I've also noticed that my AEM cam gears may not be set to 0, but possibly 3 degrees advanced on the exhaust, and 3 degrees advanced on the intake..head is decked around .008", so i was about half to 3/4 tooth off. Once those are set to stock, i feel it will idle perfect.
13.5 @108 MPH-2.2 60ft(stupid FWD!) S16G @ 18 PSI/FMIC/Running on MegaSquirt II (Now with sequential fuel injection) My webpage: http://eclipsed4evr.home.comcast.net -1998 Mitsubishi Eclipse RS-T- "Toy" -1992 Plymouth Laser Turbo AWD(SOLD) -2000 Honda CR-V(daily)
#1772, "RE: Smoothed out the idle a bit wth the MS..." In response to Reply # 0
Matt,
Surely you mean that your idling with 7 degrees of advance, not 7 degrees BTDC. I have also noticed that the leaner mixtures want less timing. I don't have to worry about emissions, so I tune my engine richer with more timing and my engine seems to like that the best... at idle and cruise. On the engines I've tuned that have to pass emissions, a good compromise has been ~14.5:1 AFR and 17-19 degrees of TOTAL ignition timing... and the cars pass with flying colors.
It's interesting that moving the lambda sensor closer to the head helped the response time and thefore injector pulsewidth stability. I never could understand why some of you guys had such bad luck getting the idle pulsewidth stable, but this makes sense. How far from the turbo is your lambda sensor now? I also shoot for ~24 inches.
#1775, "RE: Smoothed out the idle a bit wth the MS..." In response to Reply # 1 Jan-30-06 06:28 AM by XtremeRS
Originally posted by dougie2 Matt, Surely you mean that your idling with 7 degrees of advance, not 7 degrees BTDC. I have also noticed that the leaner mixtures want less timing. I don't have to worry about emissions, so I tune my engine richer with more timing and my engine seems to like that the best... at idle and cruise. On the engines I've tuned that have to pass emissions, a good compromise has been ~14.5:1 AFR and 17-19 degrees of TOTAL ignition timing... and the cars pass with flying colors. It's interesting that moving the lambda sensor closer to the head helped the response time and thefore injector pulsewidth stability. I never could understand why some of you guys had such bad luck getting the idle pulsewidth stable, but this makes sense. How far from the turbo is your lambda sensor now? I also shoot for ~24 inches.
Well 7 degrees advance is technically 7 degrees BTDC, referring to crank degrees..at least thats how i've always looked at it...Also too, i noticed it idled really nice with a richer mix and more timing at idle, but it tends to foul out the plugs easier and blackens them much faster as well..not to mention getting more carbon buildup on the wideband sensor..Leaner idle wiht less timing creates a little higher EGT, around 900 F, which helps with minimizing carbon buildup too.
Right now i'd guess the distance from the turbo outlet to the sensor is approx 20-24". My o2 sensor settings are 24 samples per ignition event, 1% steps. I used to run 16 samples, but the A/F was more jumpy at idle, when the sensor was farther away. Moving it closer let me run more samples, with a less jitter of the A/F. I just seem to still get a slight lean missfire at any A/F over 14.5 or so, just a littl stumble or burble out the exhaust..I think if i can get my cams zeroed out like stock, it would run perfect at idle..Its still a street car, so im a little "idle anal" lol
13.5 @108 MPH-2.2 60ft(stupid FWD!) S16G @ 18 PSI/FMIC/Running on MegaSquirt II (Now with sequential fuel injection) My webpage: http://eclipsed4evr.home.comcast.net -1998 Mitsubishi Eclipse RS-T- "Toy" -1992 Plymouth Laser Turbo AWD(SOLD) -2000 Honda CR-V(daily)
#1776, "RE: Smoothed out the idle a bit wth the MS..." In response to Reply # 2
Matt are you still allowing the factory ECU to run the IAC? Or have you gone with another method to work with? This spring i have to get my spark running, I have been a bit hesitant with the idle surge. I noticed idle is a bit easier for me with the 024s13c code. the 022i6 code would not idle nearly as lean as the 024 will.
#1777, "RE: Smoothed out the idle a bit wth the MS..." In response to Reply # 2 Jan-30-06 07:07 AM by dougie2
Originally posted by XtremeRS
Originally posted by dougie2 Matt, Surely you mean that your idling with 7 degrees of advance, not 7 degrees BTDC.
Well 7 degrees advance is technically 7 degrees BTDC, referring to crank degrees..at least thats how i've always looked at it.
7 degrees of advance would be 19 degrees BTDC... remember the 12 degrees base that your you're stuck with if you're using the 420A crank sensor.
I'm glad to hear that you've got it idling smoother. Try aligning everything using a degree wheel... I'm sure that will fix some of your issues. It sounds like you're not too sure how well the cams are aligned right now... and considering that you've taken material off the head, you really need to use a degree wheel to get things to align up perfect. Doug
#1778, "RE: Smoothed out the idle a bit wth the MS..." In response to Reply # 3 Jan-30-06 12:29 PM by XtremeRS
Originally posted by Star Turbo Talon Matt are you still allowing the factory ECU to run the IAC? Or have you gone with another method to work with? This spring i have to get my spark running, I have been a bit hesitant with the idle surge. I noticed idle is a bit easier for me with the 024s13c code. the 022i6 code would not idle nearly as lean as the 024 will. Terry
No, at this time, i have no IAC, and no idle air control. I took out the IAC, tapped a threaded hole in the TB, and sealed up the passage with a bolt and larger washer, just large enough to fit inside the TB IAC outer hole(youd have to look at it to see what i mean i suppose). With just unplugging the IAC, after boosting, the pintle would get pushed in, and the idle would be way up. Its a temporary solution for now, and works fine in warmer weather, just hold the gas pedal down a little to fire it up and hold it there for a minute or so..then its fine. It really does suck though this winter as i'm running the engine every week as the car sits for the winter..still need to fine tune the cold starts when its this cold, but i dont drive it this time of year, so no big deal.. A simple idle solution would be to use an air valve that can be easily controlled by the MS which lets in air for warmup and after a certain temp, shut it off. Its not fancy, but it would suffice just fine i would think. I'm still using the 022i6 code too...its running fine with it, so why bother..its a PITA to switch codes all the time.. Most of the idle A/F issues seemed to be much worse when running low impeadance injectors, and larger flow rates. Now i am running the Accel 44lb high impeadance ones, which work very well. I can prob get away with 18 psi on these injectors, but it may be pushing the PW to high..
13.5 @108 MPH-2.2 60ft(stupid FWD!) S16G @ 18 PSI/FMIC/Running on MegaSquirt II (Now with sequential fuel injection) My webpage: http://eclipsed4evr.home.comcast.net -1998 Mitsubishi Eclipse RS-T- "Toy" -1992 Plymouth Laser Turbo AWD(SOLD) -2000 Honda CR-V(daily)
#1779, "RE: Smoothed out the idle a bit wth the MS..." In response to Reply # 4
Originally posted by dougie2
Originally posted by XtremeRS
Originally posted by dougie2 Matt, Surely you mean that your idling with 7 degrees of advance, not 7 degrees BTDC.
Well 7 degrees advance is technically 7 degrees BTDC, referring to crank degrees..at least thats how i've always looked at it.
7 degrees of advance would be 19 degrees BTDC... remember the 12 degrees base that your you're stuck with if you're using the 420A crank sensor. I'm glad to hear that you've got it idling smoother. Try aligning everything using a degree wheel... I'm sure that will fix some of your issues. It sounds like you're not too sure how well the cams are aligned right now... and considering that you've taken material off the head, you really need to use a degree wheel to get things to align up perfect.
ahhh i see what you mean...brings up an interesting question though, does the 420a decoder include this 12 degrees when using/displaying the timing advance in megatune? Or persay, are we seeing/adjusting total timing? I am assuming that when we put in lets say "0" degrees, the total timing advance would be 12 degrees?
13.5 @108 MPH-2.2 60ft(stupid FWD!) S16G @ 18 PSI/FMIC/Running on MegaSquirt II (Now with sequential fuel injection) My webpage: http://eclipsed4evr.home.comcast.net -1998 Mitsubishi Eclipse RS-T- "Toy" -1992 Plymouth Laser Turbo AWD(SOLD) -2000 Honda CR-V(daily)
#1781, "RE: Smoothed out the idle a bit wth the MS..." In response to Reply # 6
Originally posted by XtremeRS ahhh i see what you mean...brings up an interesting question though, does the 420a decoder include this 12 degrees when using/displaying the timing advance in megatune? Or persay, are we seeing/adjusting total timing? I am assuming that when we put in lets say "0" degrees, the total timing advance would be 12 degrees?
No, the decoder does not remove 12 degrees... we still have that as a base. The values that you put into MegaTune are strictly timing advance values. For example: if MegaTune shows 0 degrees, the spark will still be timed 12 degree BTDC. Doug
#1783, "RE: Smoothed out the idle a bit wth the MS..." In response to Reply # 8
Originally posted by Avenger Side topic Doug. What degree wheel are you using line up your cams? Care to give a rough step by step?
I'd like to second that. My idle is horrible with the overlap from the standard crower 2's and also my head was shaved for flatness, so the timing has got to be off slightly. I've got adjustable cam gears as well, but I'm not completely comfortable messing around with those...yet.
This is a great topic btw, I always look forward to reading advanced discussion.
#1784, "RE: Smoothed out the idle a bit wth the MS..." In response to Reply # 9 Jan-31-06 09:01 AM by dougie2
I really don't have a lot of time to do a thorough write-up, but there are a lot of write-ups that already exist on the interest. Just do some simple google searches and you'll find exactly what you need to do.
As far as degree wheels, Summity Racing has an okay selection. The bigger, the better (more accurate). I use a MOPAR 7" wheel.
