Anyone ever have their 12v idle go down? The idle was low on my 96 when I bought it, and I turned it up a little, to about 750 RPM. I have been driving it for a few months and now I have noticed that the idle has dropped back down to about 500 RPM. It doesn't stall yet, but sometimes seems like it's gonna, otherwise I never would have noticed.

I'm gonna turn the idle back up, but I wonder if there's anything else I need to be concerned about, or should check, if I haven't left the idle screw lock nut loose.

Thanks,
Chris

 

I have noticed on these pumps, that the top of the idle screw will wear where the lever rests on it. I think that's the most common cause of the idle dropoff on our trucks.

 

Hmmm, I'll have to look for that when I adjust it again.

Thanks,
Chris

 

Could be your timing is slipping as well, my idle dropped a couple of times and when i went to get my timing bumped to 15* the tech said it was at 7* instead of the factory 13*. Apparently the nut is not torqued properly at the factory and it is quite common for them to come loose. He said most rigs come in at 7 *or 9*.

 

I'm thinking that timing is not the issue. This is because I did a timing bump a while back, and we torqued it down to 165 ft lbs. If I find no wear on the screw, and it is tight, I will probably go back and check the timing though.

One other thing, I do have a little seepage from the injectors. I suppose it is coming from the return lines, but I have not dug deep into that yet. I have heard there is a kit that contains the necessary replacement parts for the return lines, but I have not found a part number yet.

Thanks,
Chris

 

I'm having the exact same problem. I just came on the forum to do a search for it and this thread happened to be the very first one. When I first bought the truck a few months ago, the idle was set at about 650 rpms (no A/C). When I first turn the truck on when it's cold, it idles at about 500 then goes up to 650 after about a minute. However, recently it idles at about 550 even when warm and it does feel a little like it's going to stall.

 

My feeling is your driving habits are what cause the the idle to change more often on some rigs that others.
Namely it boils down to the amount of idling the engine does, could be city traffic.
When idling the screw hits the stop while engine vibration hammers away at it, the screw in effect gets pounded shorter.

 

I agree with what Infidel says. He knows these trucks as well as anybody and it makes sense to me.

On a timing note, I called the nearest diesel injection service the other day to set up an appointment to get my 97 timed. This shop is known to be the best in Southwest Ga. and when I told the tech what I wanted, he asked what my truck was doing wrong. I told him "Nothing, just want to check the timing and make sure it is within spec." I had already told him I had a 12 v Cummins and he said "I would not worry about it. If it is running smooth, getting good fuel mileage (I get about 20 on the road) and not smoking unecessarily, there is no need to fool with it." That coming from a person who I was ready to throw my money to in order to check it. Kind of blew my mind.
Chris

 

Still haven't had a chance to mess with it, but thanks for the info.

Chris

 

Hmm.. I fixed the idle today. I didn't have a separate tach so I just used the one in the dash. The rpm needle is just a little above the first white mark under the 1000 mark. It was kinda a pain the butt to find the adjustment screw especially since the diagrams from dodgeram.org and my Haynes manual show it upright but it's actually slanted on the engine.

 

I am having the same problem finding the idle adjustment screw. Anyone have photo or a better description of where this screw is? Thanks...oh yea I have a 1996 2500 CTD 4x4 thanks.

 

Try clicking this http://dodgeram.org/tech/dsl/adjustm...d_Gen-Idle.htm

 

Thanks for the reply. I had continued looking through the "idle" threads found under the search function and found:

https://www.dieseltruckresource.com/...highlight=idle

Where I found the info I needed. This site is great, problem solved. Thanks again!

 

I wonder if replacing the exsisting bolt (10mm adjustment screw)with a hardened bolt would help??

Or maybe it will just send the wear over to the throttle lever that rests on the adjustment bolt???

Mine has a pretty good groove in it, and it seems once the groove is in there, it wears a little faster each time. Kevin