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We are privately owned, with access to a professional Diesel Mechanic, who can provide additional support for Dodge Ram Cummins Diesel vehicles. Many detailed information is FREE and available to read. However, in order to interact directly with our Diesel Mechanic, Michael, by phone, via zoom, or as the web-based option, Subscription Plans are offered that will enable these and other features.  Go to the Subscription Page and Select a desired plan. At any time you wish to cancel the Subscription, click Subscription Page, select the 'Cancel' button, and it will be canceled. For your convenience, all subscriptions are on auto-renewal.

2001 24v Cummins High Idle Issue

Posted

Guys I am at a loss. I HOPE someone can help me, this is frustrating.

 

Bought my first 24v Cummins, it’s an 01, 3500 dually, and 5 speed nv4500. 

 

She fires up beautifully, idles normally. Then it gots warm and it idles up, stays around 1500rpm or so.

 

The tachometer isn’t working, I tried replacing the camshaft position sensor and it didn’t fix the tachometer, maybe communication issue? 
 

Does the CPS have anything to do with idle? OBD2 computer says idling at 1500rpm.

 

The APPS sensor was replaced, and voltage set. Stays below 0.50 volts, around .44-.48.

 

According to the sensors live data reading, the voltage is all over the place for the other sensors too, the apps sensor is fluctuating bad, between 0 and 5v, and same with other sensors that are sensitive to voltage.

 

I just redid the four battery terminals, grounds were in horrible shape, but the other ends going to the block and chassis are healthy.


When I put a voltage meter on the APPS, I get very small fluctuations from .44 to .48, but the live data is freaking out.

 

Things I’ve done:


1. Calibrate APPS with Multimeter on the orange/black wire coming, while setting voltage.

 

2. Checked alternator, it is consistent and I couldn’t find any alternating current in the system. (Unless I need an oscilloscope to see this?)

 

3. Checked all connections, the ECT sensor, the ground straps, everything.

 

4. Replaced IAT sensor

 

5. Replaced CPS..

 

Edited by DanTheMan

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  • Mopar1973Man
    Mopar1973Man

    I'd never do a P-pump swap. Horrid idea being 100% of all my member that did this swap ended up buying a newer truck or just parking it. Unreliable, too smokey and a cop magnet, or the fuel milage dro

  • Mopar1973Man
    Mopar1973Man

    Auto Computer Specialist will rebuild wiring for you.

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Check the PCM ground to the passenger battery. The PCM is not grounded by it's case.

Have you done the blow-by test with the oil cap yet. if it bounces around while setting over the hole you have bigger issues. 

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@Mopar1973Man Thank you sir for the information. You rock. Nice truck, I followed you on TikTok.

 

@Great work! I’ll check the ground, thank you. And also, yes the blowby is zero. Although it could be (if it has blowby) blowing out of the hole where the lift pump used to be that someone sealed off with cardboard… Once I get it sealed off, I’ll check again. 

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Welcome To Mopar1973Man.Com LLC

We are privately owned, with access to a professional Diesel Mechanic, who can provide additional support for Dodge Ram Cummins Diesel vehicles. Many detailed information is FREE and available to read. However, in order to interact directly with our Diesel Mechanic, Michael, by phone, via zoom, or as the web-based option, Subscription Plans are offered that will enable these and other features.  Go to the Subscription Page and Select a desired plan. At any time you wish to cancel the Subscription, click Subscription Page, select the 'Cancel' button, and it will be canceled. For your convenience, all subscriptions are on auto-renewal.