Yet again, another idle surge

[livedsm4g63]

Well I just switched to speed density and Im fighting an idle surge so it is hindering me from getting airflowperrev to .25
For starters there is no boost leaks.
I tested a throttle body and stock injectors from a buddies car that runs smoothly at idle. All sensors were his as well.(no change)
I have a blocked off egr valve.
My isc reads around 30 at idle. Give or take due to the idle surge.
Im really starting to run out of ideas on what could be causing this idle surge. I feel when it starts to idle ok, it is leaning out which means that im not getting enough fuel.
Just thought i would post this up to see if anyone has any other ideas. I just got v3 and did my tps adjust and my idle switch is at the 1 position. So the ecu knows it should be idling.

 

[Absit]

Check your throttle cable tension for being too tight. Is your idle switch engaged when you're idling?

 

[livedsm4g63]

Yes it is engauged. It reads 1 in eculink while iding. Cable is just right.

 

[gtbread77]

Theres only 4 things it could be....
Dirty Throttle Body
Leaking (or missing) Base Idle Set Screw (BISS)
Malfunctioning EGR Valve
Malfunctioning ISC (Idle Speed Control)

 

[avenged5]

Follow this.

Terry's Talon Troubleshooting Tips #3 - Fast Idle (aka. Idle Surge)

 

[AlaskanDsm]

Theres only 4 things it could be....
Dirty Throttle Body
Leaking (or missing) Base Idle Set Screw (BISS)
Malfunctioning EGR Valve
Malfunctioning ISC (Idle Speed Control)

And if it's none of these, then it would most likely be the FIAV...

 

[livedsm4g63]

Well since i said i tested a throttle body off a friends car that doesnt idle surge that would be out of the question. I dont have an egr like i stated. My biss screw never leaked under a boost leak test. And my isc is moving in and out via eculink, and when i took it out to see for myself it moves as well.

 

[92AWDHX40]

Terry's Talon Troubleshooting Tips #3 - Fast Idle (aka. Idle Surge)

 

[avenged5]

Terry's Talon Troubleshooting Tips #3 - Fast Idle (aka. Idle Surge)

We posted this twice because its that good.

 

[cficare68]

One another possibility that is not on that list also could be your ECU. I have Idle Surge on mine as well. Come to find out that the ECU was the cause of it. I had sent my ECU to ECM Tuning to have my DSM link installed and they advised me that one of my caps had a leak and melted the sink wrap underneath it. In the process of doing so it destoryed three of the resistors, one of which being the resistor for the ICS.

 

[gofer]

What do the RPM's do when you screw the BISS all the way in?

It seems like you're ready to thrown in the towel on this one, as I would be close too. Pull and inspect your spark plugs, keeping track of the cylinder they were pulled from, and see if they all look the same.

 

[crazyquik22023]

Is your idle switch adjusted properly? I recently, still might, have this problem. I was completely missing my idle switch on my 1g TB and didn't even notice. Make sure its adjusted properly our your TPS and ISC both won't function right.

 

[livedsm4g63]

I have to adjust my idle switch because it only reads half of the time of being in idle. Once it sees its in idle it stays around 1000 with a lot less surge. Still does it a little though. Not to worries about it. My isc did fry that's why I switched to speed density because I sent it in for the repair and upgrade to v3.

 

[VictorC777]

Quick troubleshooting! If you unplug the idle switch and the RPMs shoot up and stops surging then you have a vacuum leak. I bought the FIAV block off plate and viola! idle surge fixed! It turned out to be either the FIAV (1st bypass) or the ISC (2nd bypass) which is 2 of the 3 ways air can bypass the throttle body butterfly valve. I just adjusted the BISSS (3rd bypass) manualy to about 1000 RPMs and done!