Surging at idle this morning

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Feb 13, 2015 | 11:22 AM

busflyer

Thread Starter

Mountain Pass

Joined: May 2007

Posts: 108

Likes: 1

From: KY

Surging at idle this morning

First time event for me. SG II showed a coolant temp of 22*. Had it plugged in but I'm pretty sure I've got a bad extension cord so no heat this morning unfortunately. Truck started up just fine and I backed it out of the wifes way, pulled back up the drive and let it run for a couple of seconds and it started jumping up in idle like I was revving it with my foot. 1000RPM up to about 1250 and back, half a second pause and repeat. Did it about 6 times and then I tapped the accelerator to see if I could get it to calm down. That stopped the un-commanded revving but it settled in at a really high idle of about 1150 RPM before it slowly climbed down to a "normal" cold start idle of about 900 revs.I didn't have the presence of mind to jump through the SG II display and check the other parameters. FICM Main was a strong 48.5 volts but thats all I had pulled up other than oil and coolant temp and batt voltage. Do i have an accelerator potentiometer going hinky or is it something else. Any ideas are appreciated.
Thanks,
Eric

Feb 13, 2015 | 11:35 AM

npccpartsman

Hotshot

Joined: Dec 2003

Posts: 15,368

Likes: 121

From: Stuttgart, Ar

Pull the EGR valve and clean it then pull the IPR valve and check the screen for trash.

Feb 13, 2015 | 04:24 PM

RideDiesel88

Senior User

Joined: Jun 2012

Posts: 475

Likes: 0

Check icp volts

Feb 13, 2015 | 09:58 PM

04badford

Lead Driver

Joined: Sep 2012

Posts: 7,821

Likes: 93

From: Manteca,Ca

take the grey clip off and look in between the three wires, if white looking then it's shorting out causing your Issue, you can also do a wiggle test with the engine running.