idle surge problem on newly built motor...

[gritsak]

i just finished up putting back together my car a couple weeks ago and am having an idle surge problem...heres the story...

car starts up fine and idles pretty steady for the first couple minutes. right about when its time for the fan to kick on the idle starts bouncing from around 1k up to 2k rpms up, down, up down...and my fjo is reading the a/f bouncing from around 15:1 up to 20:1.

the only way it stops and goes to normal (well still is idling a little high, but at least its steady) is when you ground the ignition timing plug....i tried to adjust the biss screw, but with both the ignition timing plug and the diagnostic plug terminal 10 grounded it starts to surge again. but if you take off the diagnosis plug ground (and leave the ignition timing plug grounded) it goes back to idling steady again.

ive tried messing with everything and cant figure it out..any input would be appreciated...heres a quick rundown of my mods just in case

2.3 built stroker, vpc, afc, 720cc injectors, 255 pump, agp 60-1 kit, ect...

 

[sonicnofadz]

You might want to test your Idle Speed Controller (ISC). If yours is like mine (completely destroyed) this will cause your idle to be really wacky. I've found that it is not needed, and I just unplug mine, and adjust the BISS screw to the desired idle speed. My idle NEVER surges and my car purs like a kitten =)

 

[Liquid Illusion]

Does it idle normally once the motor reaches operating temperature. Your fuel setup is identical to mine and my idle is a mirror of yours until it warms up.

 

[gritsak]

Originally posted by Liquid Illusion
Does it idle normally once the motor reaches operating temperature. Your fuel setup is identical to mine and my idle is a mirror of yours until it warms up.

its once it reaches operation temp that it starts to surge bad...i had the same turbo/fuel setup before with the stock motor and it didnt have any issues...

its just weird cause as soon as i ground the ignition timing adjustment plug it idles steady

 

[4twenty]

Sounds like your ISC motor. There is a vfaq on how to test it.
J

 

[L2RTSiAWD]

Moved to Problem Diagnosis.

 

[gritsak]

aight ill try the isc motor this weekend if i have time..hopefully thats it