engine surging?

[wb1895]

Okay heres the problem...

My deuce will run just fine at an idle for several minutes at around 650-700 RPM. But after sitting for about 5 minutes the motor will start surging up to around 1000 RPM and then drop down to around 400 RPM then back up again. If I step on the gas pedal for a second it will smooth out for a little while before starting up again. Also, while driving the truck while down shifting, when I push in the clutch the engine will drop down to almost 300 RPM then come back up to regular idle speed.

This began after I changed the fuel filters and gave her a oil change. The truck was running just fine before and began doing this just after I finished changing everything out.

 

[63sierra10]

I would check the seal on all of your filters. It sounds like you are getting air in the lines. Good luck.

 

[glcaines]

Ditto on the air in the fuel lines. It might also be a faulty in-tank fuel pump? I had a Deuce do this when in the Army. It was much worse than what you are describing. It surged constantly, even when being driven. The motor pool repaired it very quickly, but I don't remember what was wrong.

 

[stampy]

You might also check your filters just to be sure they are clean!

 

[JDToumanian]

I don't doubt that air in the lines can cause some odd symptoms, but surging? ....It's not like a carbureted car that will speed up as it leans out and starves for fuel, but who knows. The older I get the less I know. It's sad, I was such a genius when I was a teenager.

To me it sounds like the beginning of injector pump trouble. Some surging upon cold start up is normal "governor hunting", but it should go away when the engine warms up.

These pumps appreciate some lubricant in the fuel.... It will reduce wear and can prevent hydraulic head sticking or failure. I use a quart of 2-stroke oil per tank of fuel, but there are a lot of good additives out there.

Jon

 

[wb1895]

I checked the fuel lines and all of the filters.....There was no signs of leaks, bad seals or air in the lines. The truck seems to just be moody .........Sometimes she idles just fine, sometimes she surges just a little, and sometimes she will stall out......

 

[JDToumanian]

....one broken governor spring comes to mind also. Have you looked in the troubleshooting manual yet? You can download it here on SS...

 

[marchplumber]

I hope someone smarter than me does figure this one out for you, cause my deuce is doing the same thing, to the extent that it dies when you push in the clutch after a 2100 rpm run. Other times, runs fine. Argh, intermittent problems are the worst!
God bless,
Tony

 

[BrianScott777]

What was the cause / fix? I know its been 7 years but ya'll left me hanging, and now my truck is surging and dying out while in 6x6

 

[wb1895]

It decided to stop on its own. I figured it was just some gunk breaking loose, after sitting for some time before I got it.

 

[BrianScott777]

I changed the fuel filter and no more surging