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Idle issues
Posted: Thu Apr 27, 2006 10:28 am
by scirocco_per
Rough idle(800-1300rpm), might stall unless give it a little gas in neutral.
I have build a engine 1900cc, eaton M45 superchager, ic and megasquirt (fuel and spark) and my problem is my idle is 1500rpm if I lower it is jumping 800-1300rpm.
I have try to seek vacuum leeks and look in the fuel tabels for diffrents in the idle area but nothing.
http://www.scirocco53.net
MS-I/MSnS-E V3
Posted: Thu May 18, 2006 4:00 pm
by Jim
Check your "EGO Sensor Authority" settings .
The EGO Sensor will cause ocillations if it is operating at low speeds and is
capable of making large changes to the AFR .
It should be set to operate only above ~1500 rpm ,
and the "authority" should be 5% to 3% .
Also , check your injector pulse width at idle ,
if it is less than 1.5 ms it may cause idle instability .
Let me know what you find .
...................Jim
Posted: Fri May 19, 2006 11:56 pm
by bertelli_1
Does the car have an idle screw? This may need to be adjusted. Also make sure you are tuning for the lowest MAP reading at idle, not a lean mixture. If the car has an idle control valve which you are not using it could be letting air through and giving you false readings - clamp it off. Why not post a datalog of your problem? It would make it easier for people to understand the problem.
Posted: Sat May 20, 2006 6:19 am
by scirocco_per
I remove the supercharger kit and the engine and idle works fine, and rebuildt the pipes for the superchager and mount a 2-wire VDO pwm valve.
http://www.msefi.com/viewtopic.php?t=19053
Posted: Sun May 21, 2006 12:36 pm
by mops
hunt any vacum leaps you might have.
less ignition timing will product lower idle.
Posted: Mon May 22, 2006 11:04 am
by scirocco_per
Posted: Mon May 22, 2006 11:45 am
by keithmac
It maybe due to the charger loading up the engine, requiring a richer mixture and a change in ignition timing?
I run 10 degrees advance at idle.
Posted: Mon May 22, 2006 12:03 pm
by scirocco_per
No my charger have a boost valve, it is open when the engine is idle and on low load.
Giv me more clue!
Thanks
/Per
Posted: Mon May 22, 2006 12:42 pm
by mops
dude, i looked at your logs and 19-23 degrees timing at idle is way too much. you have to reduce that - ty 15, 12, 10, 8, 6 degrees untill you reach desired idling rpm.
