Rough idle at 750 rpm

[GSchneuer]

I have an engine with a mild rough idle at 750 rpm in nuetral and continuing up to about 1800 rpm where it smooths out very nicely.



Engine has 88,349 on the clock. Damper looks good and tight, other then that, I don't know where to start looking. So I need some pointers from you folks?.



Thanks,

Gary

 

[BIGNASTY]

... ... ... ... Quote



So I need some pointers

 

[Prairie Dog]

I would start out by replacing the FCA on the CP3 pump. It's notorious for this kind of thing. You can get one from Geno's for about $135.

 

[JLandry]

A long shot, but have you checked the oil level?



John L.

 

[p-Bar]

Try dumping some 2 stroke il in the fuel tank and see if it smooths out . if it does it's the FCA

 

[LNaugle]

valve adjustment?

 

[Mark31]

Hey Nastyfinger, that is in the same class as the orange snakes chasing the trucks out of the garage in the winter!! Mark

 

[BIGNASTY]

Hey Nastyfinger, that is in the same class as the orange snakes chasing the trucks out of the garage in the winter!! Mark

I dont have orange snakes I have ESPAR the only way to HEAT

 

[Maverick]

Check your fuel! The last time I saw this same problem was a 2006 45,000 mile truck in the shop checked all the common things could not fix until fuel change and powerservice 2 stroke. Truck has run great since 6 months ago possible gas in fuel from a station that customer has never use before. Good luck.

 

[GSchneuer]

Thank you for all the help you guys offered me with my rough idle problem.
I did the oil in fuel and FCA replacement, but that was no help at all. The problem came to a head as I was towing my 5th wheel in Western WA.
I had justed crested a long climb hill and when the transmission shifted back into O/D, the dangest noise I have ever heard came from under the hood, I pulled over for a look see but I could not see any damage so I drove out of harms way and called for a Tow. I was towed to Tom Matson Dodge in Auburn where the problem was found. Two bolts securing the T/Converter had become very loose with one falling out and the other four where also pretty loose. These six bolts had blue loctite on the threads but it didn't even look like it held as there was a lot of loctite still in the threads.
All holes where cleaned and checked for being stripped as was the T/converter, all six bolts were replaced with new ones with blue loctite, Dodge says they should have red loctite, but the S/Advisor said that once you use it, the bolts are real tough to get out.
Now my truck runs very quite and smooth again, just like new, spool up and shifting is very crisp once again and I am a happy camper. Moral of this story is if you are having a rough idle problem, look at the T/converter bolt torque, it only takes a few minutes to get the inspection cover off & have a look see. Injecters aren't the only problem for a rough idle condition.

Thanks again,
Gary

 

[Prairie Dog]

That's a strange one indeed! Thanks for updating us.

 

[cerberusiam]

That is typical when powering up the engine and\or towing heavy and not replacing the TC with a billet cover unit.

From your sig it looks like the trans was replaced and I'll bet the installer did not use new loctite. Figured since it was still blue just put them back in, doesn't work.

I have had 5 of these units out in the last 2 years and they had blue loctitie on them from the factory. Whomever at Dodge said it should be red is doing the CYA dance cuz they ain't delivered that way.

If you have have any power adders or tow a lot, checking those bolts once per year as a maintenance issue is a good idea. I have caught 2 of my trucks starting to walk them loose after replacement.