idle tuning

For discussing MicroSquirt (TM) configuration and tuning of fuel parameters (including idle valves, etc.).
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Read the manual to see if your question is answered there before posting. If you have questions about MS1/Extra or MS2/Extra or other non-B&G code configuration or tuning, please post them at http://www.msextra.com The full forum rules are here: Forum Rules, be sure to read them all regularly.
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myjadezxt
MegaSquirt Newbie
Posts: 3
Joined: Fri Dec 03, 2004 5:16 am
Location: Chicago
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idle tuning

Post by myjadezxt »

I am still having trouble tuning my lower-than-1200-rpms area. My idle is around 6-700 and I would love it to be at 900. How can I change the idle speed? Also, my accel enrichments are at .1, .2, .4, and .8 and it STILL chugs when I rev the enigne... (but it's better) What's going on there?
BottleFed70
Helpful Squirter
Posts: 91
Joined: Fri Jun 24, 2005 2:22 pm

Post by BottleFed70 »

Assuming your mixture and timing are good, the proper way to increase idle speed would be to allow more air to enter the engine.

Either by adjusting your Fast Idle/Idle Air Controller, or by adjusting the throttle plate itself.

If you are controlling timing with your MS, try upping the ignition advance at idle and see if that helps...
1970 Ford Mustang
MSII, v3.0 PCB, v2.36 firmware, Megatune 2.25
mops
Experienced Squirter
Posts: 217
Joined: Sun Sep 25, 2005 4:13 pm
Location: Auckland, NZ
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Post by mops »

dont want to steal the thread, but getting idle tuned is vaguely described in the manual.

I just got my MS2 installed in my beemer.

aswell, i'm just trying to get it to idle right now, and so far I'm not winning.

It starts every time (thats the good part, now the bad part)

I cant get stable idle. stock idle ~800rpm, the best I can get is slowly varying between 700 and 900 rpm. It's pulling only between 40 and 50 kpa of vacuum, and idleing like that it warms up very quickly... I mean very quickly... within few minutes coolant is up to 90 deg C. There's alwell water comming out of exhaust... I havent tried altering ignition yet, I need to get timing light and make sure i have correct base timing first.

I think it's running lean, but my ve table in that region is 50~60, which I think is pretty high as it is. My problem is that I'm a noob and i dont knoww how to tell whether it's rich or lean or bad timing....

I have PWM idle valve, so I can precisely adjust idle air to the engine, but I dont know whether it is better to allow lots of air and pump small amount of fuel or the other way around

Basically all I know about tuning idle is that the lowest MAP is the best. but i'm not sure how to achieve it. I tried altering air and fuel to the engine and it doesn't seem to have significant effect to map... my map sits between 40~50 (at warm engine it's about 43~44kpa)

any syggestions ?
BMW, 1985, E30, 325i, 2-door, 5spd , 127k miles, short shift, MSII, V3/code 2.684/60-2 wheel/MT 2.25, LC-1 wbO2, ignitor module mod driving msd coil/, 3 pin Bosch PWC IAC mod
ChaosAD
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Posts: 10
Joined: Tue Dec 21, 2004 9:48 pm

Post by ChaosAD »

I had the same problem with an unstable idle. Wideband said it had an afr of about 4:1 (very rich) and diddnt have much vacum. then I richened it up to almost double the ve and now it idles fine, has much stronger vacum and has an afr of 14.7:1
keithmac
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Joined: Sun Jun 19, 2005 11:52 am
Location: UK, York

Post by keithmac »

I`ve had real problems with my cammed VW16v, finally getting there with KeithG`s take on the MS1 Extra-firmware. I run a pwm idle valve and you can see it reacting in mt to the engine to maintain a steady idle, plus I need a lot more air when cold than when hot.

I`d love to have a separate spark table for idle, so the timing could be fixed up to 1500 rpm at 6dbtdc and mappable below 1000 with the throttle ADC as a trigger, problem for me is the MAP is very similar on and off throttle so the ignition will advance up to 1500 where it needs to be flat really.
Squirted VW GTI 16vG60 mk2
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