2000 Cummins Surge/Dead Pedal

[DunnerCummins24]

Hey guys! 
 

Thanks again for all the help, truck ran the best it’s ever ran for 3 weeks after the ground mod. 
 

Then Friday morning took off for work and coming to a stop at the first stop sign the idle was staying high, kicked up a couple times and kind of just drove through it and really tried to keep it moving and once temp started coming up it ran fine. Ran fine on the way home.

 

Then this morning was leaving to go help with picking up hay, fired the truck up and went inside and heard the idle kick up so ran out and was around 1200 so watched it and kicked back down after 30 seconds or so and then it went up to like 2k so I shut the truck off, fired it back up and just took off. Ran fine all day, picked up 3 loads of high, truck was on and off, drove 2 hours total after to pick something up. Ran great all day. 
 

I did check AC volts Friday when I got to the shop and it was fine with the truck warmed up, haven’t checked in the morning. 
 

Was thinking maybe when I had the excessive AC noise maybe it did something to ECM, VP or alternator? But why would it be good for 3 weeks and then come back and only happen when cold? 
 

Was thinking of installing a high idle to try and get it up to temp quicker but don’t want to bandaid an issue if something else is going on. Thanks again! 

[Tractorman]

Well, that's a bummer!  Any codes?

 

You could hook up a scanner and monitor the throttle position on the display.  Drive the truck and when the symptoms occur at idle, see if the per cent of throttle changes on the display, or if it remains steady as it should. 

 

I think that you may still be getting an electrical interference of some kind.  I don't know much about the ECM operation, but I think the ECM has the capability to monitor and weed out false signals.  However, if too many false signals are being sensed in a specific amount of time, the ECM may consider the signals to be valid.  The APPS provides one of those signals.  It may be worth a try to leave the ignition switch in the "Run" position and slowly depress the throttle to the floor one time and release.  Turn the ignition switch off and then start the engine.  This is not a fix, but if there is electrical interference with the APPS, then the symptoms may disappear for awhile.  This may help to diagnose what is really going on.

 

- John

[DunnerCummins24]

On 8/24/2024 at 9:46 PM, Tractorman said:

Well, that's a bummer!  Any codes?

 

You could hook up a scanner and monitor the throttle position on the display.  Drive the truck and when the symptoms occur at idle, see if the per cent of throttle changes on the display, or if it remains steady as it should. 

 

I think that you may still be getting an electrical interference of some kind.  I don't know much about the ECM operation, but I think the ECM has the capability to monitor and weed out false signals.  However, if too many false signals are being sensed in a specific amount of time, the ECM may consider the signals to be valid.  The APPS provides one of those signals.  It may be worth a try to leave the ignition switch in the "Run" position and slowly depress the throttle to the floor one time and release.  Turn the ignition switch off and then start the engine.  This is not a fix, but if there is electrical interference with the APPS, then the symptoms may disappear for awhile.  This may help to diagnose what is really going on.

 

- John

Hey John,

 

Thanks for the reply, was away for a bit and then was driving my TDI Jetta, have been driving the truck, the pedal reset seemed to work for a couple days. Then it started acting up again, now that it’s happening on almost every single drive I’m going to check the throttle position on the scanner while it’s doing it. But it seems to be getting worse. 
 

It’ll be revving high when I’m trying to come to a stop, doing it at idle or even while cruising it’ll surge up and then come back down. Saturday I fired the truck up and it went straight to 2k RPMs, shut it off and turned it back on and it was fine, kicked up a bit leaving but like before once up to temp it’s USUALLY okay, it has done it the odd time once warm but it’s rare. 
 

It’ll throw a code still but won’t dead pedal, it throws a P0222 Idle validation signal code. A weird thing I noticed if I plug my mini scanner in it takes forever to get all the monitors to run, but the CEL just disappears when you plug it into the OBD. No issues with snap on scanner. 
 

Is it possible I have an injector issue or oil issue causing it to idle up like it has been? 

[Tractorman]

2 hours ago, DunnerCummins24 said:

It’ll throw a code still but won’t dead pedal, it throws a P0222 Idle validation signal code.

 

P0222 (M) Idle Validation Signals Both Low Problem detected with idle validation circuits within APPS.

 

I would definitely find out why you are getting this code.  If the ECM does not get a signal for idle validation, then the engine rpms will not go to idle.  Which APPS are you using now - OEM or TImbo?  Either way, you could try adjusting the mechanical stop where the APPS is located in the engine compartment.  Back it off an extra distance to ensure the throttle will activate the idle validation switch that is built into the APPS.

 

2 hours ago, DunnerCummins24 said:

Is it possible I have an injector issue or oil issue causing it to idle up like it has been?

 

I seriously doubt that.  An injector misfiring would likely cause a miss or a timing knock.  Engine oil feeding a cylinder wouldn't allow the engine to shut off immediately when you switched off the ignition.

 

I think the P0222 in telling you something.  Double check all of the pin conditions in the connector to the APPS. 

 

- John

[DunnerCummins24]

22 hours ago, Tractorman said:

 

P0222 (M) Idle Validation Signals Both Low Problem detected with idle validation circuits within APPS.

 

I would definitely find out why you are getting this code.  If the ECM does not get a signal for idle validation, then the engine rpms will not go to idle.  Which APPS are you using now - OEM or TImbo?  Either way, you could try adjusting the mechanical stop where the APPS is located in the engine compartment.  Back it off an extra distance to ensure the throttle will activate the idle validation switch that is built into the APPS.

Thanks for the info John! 
 

I have the timbo APPS, do you think it would be worth back probing the green wire and adjusting the set screw? I know the previous owner had an issue with the set screw backing itself out but this is an entirely different assembly than what he had when that happened. 
 

[Tractorman]

On 9/16/2024 at 5:30 PM, DunnerCummins24 said:

Then it started acting up again, now that it’s happening on almost every single drive I’m going to check the throttle position on the scanner while it’s doing it

 

I would do this step, first.  It would be good to know whether or not a false signal is being generated at idle.

 

Since the DTC states, "Idle Validation Signals Both Low Problem detected with idle validation circuits within APPS", I would double check the wiring condition and connections from the ECM to the APPS - and, maybe try another APPS, if you have one available.

 

Also, I believe that you said you did the W-T wiring modification.  If so, re-check your work regarding Splice #165 - the ground for the APPS, ECM, and other sensors.

 

- John

 

 

 

Edited September 18 by Tractorman