Idle issues

scirocco_per · Post by **scirocco_per** » Thu Apr 27, 2006 11:28 am

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

Jim · Post by **Jim** » Thu May 18, 2006 5:00 pm

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

bertelli_1 · Post by **bertelli_1** » Sat May 20, 2006 12:56 am

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.

scirocco_per · Post by **scirocco_per** » Sat May 20, 2006 7:19 am

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

mops · Post by **mops** » Sun May 21, 2006 1:36 pm

hunt any vacum leaps you might have.

less ignition timing will product lower idle.

scirocco_per · Post by **scirocco_per** » Mon May 22, 2006 12:04 pm

Here is the datalog,
http://www.scirocco53.net/download/data ... 222017.xls
http://www.scirocco53.net/download/data ... 222021.xls
I have seek vacum leaks but nothing

MS-I/MSnS-E V3 029q2 code and PWM valve

keithmac · Post by **keithmac** » Mon May 22, 2006 12:45 pm

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.

scirocco_per · Post by **scirocco_per** » Mon May 22, 2006 1:03 pm

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

mops · Post by **mops** » Mon May 22, 2006 1:42 pm

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.