Rough idle

[daddyo55]

hello to all. we own a 2004 Newmar Kountrystar mod #3904 with a 330 Cat. about 2 months ago we went to go on our once a month short trip and fill up the propane but about 10 seconds after I started the engine it began to idle rough. once the rpm's got to about 1500 it smoothed out and after the engine got warm the idle was also smooth. there are a few more experienced fellows here and they thought it may have been the fuel waxing up the filter due to the cold weather, ( about -5 c or 22 f ). well we've gone out 2 more times since then and now I've noticed that it's taking longer to start then usual. last weekend I replaced the fuel filter, that was fun after getting air in the line. but it got done. it did not help at all. I don't know how old the air filter is but the fellow we bought the rig from in June 2012 said he had just had it replaced. any help or suggestions would be appreciated.

[Skip426]

Many posts in the Cat engine section of the Power Train Garage, on poor performance of the Cat, ( C-7 330 HP ) HUIE injector pump , failure warning signs. Rough idle and increased cranking to start are two of the main problems, but there are other parts of the fuel system that need to operating correctly for a smooth running, easy starting, engine.
There is a back pressure valve at the transmission end of the cylinder head, that needs to be operating correctly, for proper performance.
I'll have a glace at what's there and give you the name of the best posts for info.

On the second page in the Cat Engines section, look for
Technical Article on HEUI Systems
By: moisheh
a couple of very good links to articles on the fuel system.

[moisheh]

I would not use your unit until you have this checked out by a mechanic that is familiar with the HEUI system. If the pump is beginning to fail continued use will also ruin your fuel injectors. They are not cheap!

[daddyo55]

well this does not sound good but it does sound complicated. we are looking forward to going on a 3 week trip soon and this could put a slight damper on it.

[moisheh]

How far are you from a Cat dealer? If close a quick trip to get a diagnosis would be a good idea. Maybe it is not the HEUI pump. But I have read too many stories from those who kept driving and ended up with a tow bill and a $7000 repair. Bummer when this happens before a vacation. Good luck.

[daddyo55]

thanks again guys. I think I may have 2 take it in for a quick test. I am curious about one thing though. in autos there are readers for testing and checking, are there readers for our equipment?

[calhyatt]

Originally Posted by daddyo55

hello to all. we own a 2004 Newmar Kountrystar mod #3904 with a 330 Cat. about 2 months ago we went to go on our once a month short trip and fill up the propane but about 10 seconds after I started the engine it began to idle rough. once the rpm's got to about 1500 it smoothed out and after the engine got warm the idle was also smooth. there are a few more experienced fellows here and they thought it may have been the fuel waxing up the filter due to the cold weather, ( about -5 c or 22 f ). well we've gone out 2 more times since then and now I've noticed that it's taking longer to start then usual. last weekend I replaced the fuel filter, that was fun after getting air in the line. but it got done. it did not help at all. I don't know how old the air filter is but the fellow we bought the rig from in June 2012 said he had just had it replaced. any help or suggestions would be appreciated.

The symptoms you are describing are the exact duplicates of my HUEI pump failure last year. Don't mess with it. Get it checked. My repairs were $$$$ with the contamination of the system caused by the failure of the pump. A car reader will not read codes on this engine. Take it to the Cat facility. Good luck....