Hello everyone,

 

New to the forum here, have a 2000 Dodge 24 valve. I’m a mechanic by trade, bought the the truck off one of our customers. He had this issue towards the end of his ownership, truck would surge during idle and the odd time would throw APPS code but he could still drive it. 
 

The trucks had a couple different APPS sensors, OEM and aftermarket. When I bought the truck last summer I did a ton of upgrades/maintenance, starter, alternator, 2 new batteries, FASS and sump, fuel pressure gauge and a bunch of other things non related to the problem. I did all the APPS testing between sensor and ECM and everything checked out. 
 

After doing the timbo APPS my issues seemed to go away (the alternator change was around this time too). We have a truck bed camper and went on a couple long trips with no issues. I don’t drive it much in the winter but again when I did, no issues. The start of this year also had no issues, and then things slowly started to creep back. I’d be sitting at a stop light and truck would kick up a bit, started becoming more frequent, and now it’s dead pedalling again, I’ll take off for work in the morning, I’ll be trying to come to a stop and RPMS will stay high, then 2 minutes later CEL comes on and no throttle. Takes me a while to get into the system with my scanner, I’ll clear it and I can drive but will either rev real high right away and trip the light or it’ll throw it a minute down the road again. But then if I work through it enough times, and the truck warms up enough I can get going with no issues. I can go somewhere, shut the truck off, go in somewhere and drive all the way home, again no issues. But if the trucks cold or sitting for days it’ll give me issues.

 

I checked for AC noise and am getting 0.127V, is this possibly an alternator gone bad? Like I said I replaced it last year with the timbo and was good for awhile but now a year later dealing with the same problems. Just want to make sure I’m not missing something here. Seems weird to me that it goes away when the truck warms up. Any insight would be greatly appreciated! 

Sounds like  you have been thorough in taking care of things since you acquired the truck. 

 

Have you checked the conditions of all battery connections and frame / body wiring grounds? 

 

There is a wiring modification for the VP44 trucks that is called W-T ground reference wiring mod (by William Timothy Burke).  The wiring modification addresses long wiring routes and poor ground connections for the PCM and the ECM.  This wiring mod can reduce electrical interference in circuits joining computerized components.  Here is a link to the W-T ground reference wiring mod:

 

https://mopar1973man.com/cummins/articles.html/24-valve-2nd-generation_50/51_engine/electrical/ground-reference-vp44ecmpcmpdc-plus-tc-lockunlock-r567/?do=getLastComment&d=4&id=567

 

Also, check the mechanical low idle screw condition under the hood.  You will have to remove the plastic throttle cover (if it is still there) to gain access.  Another member posted similar symptoms as yours and it turned out to be the idle adjustment screw was loose allowing for irregular throttle positions at idle.

 

- John

9 hours ago, Tractorman said:

Sounds like  you have been thorough in taking care of things since you acquired the truck. 

 

Have you checked the conditions of all battery connections and frame / body wiring grounds? 

 

There is a wiring modification for the VP44 trucks that is called W-T ground reference wiring mod (by William Timothy Burke).  The wiring modification addresses long wiring routes and poor ground connections for the PCM and the ECM.  This wiring mod can reduce electrical interference in circuits joining computerized components.  Here is a link to the W-T ground reference wiring mod:

 

https://mopar1973man.com/cummins/articles.html/24-valve-2nd-generation_50/51_engine/electrical/ground-reference-vp44ecmpcmpdc-plus-tc-lockunlock-r567/?do=getLastComment&d=4&id=567

 

Also, check the mechanical low idle screw condition under the hood.  You will have to remove the plastic throttle cover (if it is still there) to gain access.  Another member posted similar symptoms as yours and it turned out to be the idle adjustment screw was loose allowing for irregular throttle positions at idle.

 

- John

Thanks for the reply John!

 

I have gone over a lot of the grounds, battery terminals are good, did those when I dropped two interstates in when I first bought it. 
 

I’ve seen that WT mod before but out of laziness never did it, I guess maybe it is time? Was just looking at moparmans write up on it as well. Maybe that’s something I’ll get done. 
 

Has anyone on here had luck upgrading alternators to something like the XDP or mechman? 
 

Also good call on the idle screw, i will make sure it hasn’t moved. 

Yeah sadly all these trucks at some point will require some attention to the master grounds for the VP44 and ECM and then separating the alternator charge lead from the path of the negative or ground for the ECM.

 

18 hours ago, Mopar1973Man said:

Yeah sadly all these trucks at some point will require some attention to the master grounds for the VP44 and ECM and then separating the alternator charge lead from the path of the negative or ground for the ECM.

 

Yeah no kidding, will be tackling the ground mod this weekend. 
 

Only question I’ve got is the AC noise I’m getting at .127 is pretty high, will the ground mod clear that up? Or do I have an alternator issue as well? 

Start with the ground mod then retest for AC voltage.  When testing for AC voltage the engine should be warmed up and all unnecessary lights and accessories are off.

Pull the alternator and have it tested for AC ripple. Have your batteries removed and tested too. Weak batteries can bring a bad alternator way high in AC noise because extra load and trying to charge batteries with bad cells.

Edited August 1, 2024Aug 1 by Mopar1973Man

In his first post he said that he installed new batteries last summer.

 

- John

On 8/1/2024 at 10:28 AM, Mopar1973Man said:

Pull the alternator and have it tested for AC ripple. Have your batteries removed and tested too. Weak batteries can bring a bad alternator way high in AC noise because extra load and trying to charge batteries with bad cells.

 

 

On 8/1/2024 at 10:31 AM, Tractorman said:

In his first post he said that he installed new batteries last summer.

 

- John

I’m just about to order the breaker and was looking at a Blue Sea 150A, but was thinking if I do need an alternator is it worth upgrading? Are guys having luck with these upgraded alternators? Just don’t want to get a 150 breaker if i end up getting a 170A alternator. 
 

I also read something about using a quadzilla for the high idle?

I use a Blue Sea 150A fuse with the extra fuses you get in the glove box with the other spare fuses. I've never had to replace one.

 The reason I chose a fuse over a breaker was:

• the truck's stock alternator fuse is 140A and how often have you had to replace it, never?   
• An electrical breaker is mechanical and can fail. 
• If the alternator has an internal short, then resetting a breaker or installing a new fuse is no going to help. 

31 minutes ago, IBMobile said:

I use a Blue Sea 150A fuse with the extra fuses you get in the glove box with the other spare fuses. I've never had to replace one.

 The reason I chose a fuse over a breaker was:

• the truck's stock alternator fuse is 140A and how often have you had to replace it, never?   
• An electrical breaker is mechanical and can fail. 
• If the alternator has an internal short, then resetting a breaker or installing a new fuse is no going to help. 

And you just use a stock alternator? 

 

This the fuse you’re running? And just ring terminals bolted on both ends? 
 

 

Edited August 3, 2024Aug 3 by DunnerCummins24

I'm running the stock alternator.

I use a Blue Sea Systems 5005 ANL fuse block with an ANL type fuse, but the AMI/MIDI type fuse will work also.  I've done 4 trucks using this fuse setup. 

On 8/3/2024 at 12:50 PM, IBMobile said:

I'm running the stock alternator.

I use a Blue Sea Systems 5005 ANL fuse block with an ANL type fuse, but the AMI/MIDI type fuse will work also.  I've done 4 trucks using this fuse setup. 

Okay sounds good, tackling the mod right now, as for the new ground going from gear case to drivers battery is it okay if I use 4GA cable compared to the 6GA that’s used? I have brand new 4GA lying around. 
 

Also is everyone leaving this connector just open? And leaving the other ground that goes around the air box? 
 

 

4AGW is bigger than 6AGW so no problem there.  

Here is how I treated the passenger (right side) battery ground.

https://mopar1973man.com/cummins/articles.html/24-valve-2nd-generation_50/51_engine/electrical/pcm-ground-splice-repair-r675/?tab=comments#comment-115

1 hour ago, IBMobile said:

4AGW is bigger than 6AGW so no problem there.  

Here is how I treated the passenger (right side) battery ground.

https://mopar1973man.com/cummins/articles.html/24-valve-2nd-generation_50/51_engine/electrical/pcm-ground-splice-repair-r675/?tab=comments#comment-115

Alright awesome! 
 

Any issue leaving it for now and doing it later? 

Have you connected all the ground wires that are attached to the end of this cable and grounded them to the timing case and added the ground from the case to the driver side battery?  If yes, then leave it unplugged.  If no, then plug it in to the right battery until you've done this step of the ground modification.

   

1 hour ago, IBMobile said:

Have you connected all the ground wires that are attached to the end of this cable and grounded them to the timing case and added the ground from the case to the driver side battery?  If yes, then leave it unplugged.  If no, then plug it in to the right battery until you've done this step of the ground modification.

   

Yeah so I did the drivers side 4 wires to the case, then did case to drivers negative. 
 

Then did alternator to passenger side positive terminal with 150A fuse inline. 

It made sense in my head that it would be okay to leave it unplugged, so I went ahead and fired it up, and I’m gonna be honest with my previous readings of .127Vac I did not think this was going to make much of a difference, but I rechecked and .046Vac!!

 

Still higher than some peoples readings but took it for a drive and ZERO issues, truck ran the best it’s ever run since I’ve owned it. 

Also I’m not liking my fuse setup so I ordered a fuse holder and switched to AMG fuses but I’ll run this for now. 
 

 

 

Congratulations!

 

- John

I cut the lead off and used it all again. I've got the connector between the battery and gear case for an added connection and plug allows for disconnect. 

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!