I own a 1996 Dodge Ram 2500HD with the Cummins TD and 47RE auto trans. I have been experiencing a wierd problem on ocassion. I'll start the engine and all goes well, but when I put the truck in drive or reverse, it surges or lopes. It only happens on first starts of the day when the engine is cold and does not happen often. The nearest thing I can relate it too is a gas burning car when the choke sticks closed and the engine runs way too rich and surges or lopes. My truck only does it for a few minutes and only when under a load (idling in gear), no load (out of gear) it idles just fine. Anyone experience this before?
Mike

 

What is your idle RPM? Should be 750 in drive with AC on and engine at operating temps.

 

Right on the money

 

If the overflow valve hasn't been replaced in past 5 years, change it out. If problem still exists, take one click out on both sides of gov springs.

 

Not to sound stupid, but what overflow valve? Where is it located and how difficult is it to replace?
Thx,
Mike aka Alf

 

It's behind the banjo bolt on the hard fuel line on the injection pump. Order one from Larry B's and dont loose the springs and washers when you put together. Very easy to replace.

Another thing if you haven't done, take the bowl off the pre filter/ heater. Right below the fuel filter next to prime pump. I took mine off and removed the screen and cleaned well and it ran like a shot dog. There are several good videos on here and ytube to show you how.

One last thing to check while you're doing all this is to check your factory fuel lines. the braided lines going over the transmission leak and suck air. when it gets real bad you'll hear a ticking noise. They also leak from the lines that go from the tank to the frame lines. You can order marine grade diesel fuel lines to run all the way from the tank to the injector pump (recomended) or run lines to the hard lines on the frame rail. You will be pleasently surprised after these few simple fixes. Search the fuel lines and you'll see what size they are, 3/8 and 5/16 I believe and get under there and measure. Like wise search the overflow and pre filter. Keep us posted.

 

Joe G's old fuel system write up with photos. Good info with photos/drawings. Save it...

http://www.cumminsforum.com/forum/94...m-writeup.html

 

Whoops!! The prefilter has never been changed nor has the overflow valve. Got both on order.

 

You'll be surprised what a difference cleaning the pre filter makes. There's a video on here that shows you how to delete the whole thing but I just clean mine when I change the regular filter. You take an 18mm wrench and the bowl unscrews. Then inside the bowl is another nut holding the screen in. clean it all out good and I usually pump a little fuel out before I put the bowl back on to get any trash out of the lines and tank. Good luck. Let us know how it runs when you get done.

 

Check out the "delivery valve" thread by Robert Rouch. I put a pic of the overflow on there so you can get an idea of where it is.I could'nt get the pic on your thread for some reason.

 

The truck started lopping/surging today when it was hot (104 degrees). The only time you notice it is when you are in gear (D or R) and idling.As soon as I give it some throttle, it smooths out. Also, did a hard acceleration and then immediate release of the throttle (got cut off by another driver) and the engine died.

 

Sounds like it is time to get a fuel pressure gauge on there and see what she is doing.

25-27 at idle and 32-35 at WOT for the Pee pumps is considered normal.

 

Read my reply again.

 

Both the Overflow valve and the Prefilter came in today's mail, so I plan on swapping them out tomorrow.

 

Just came back from the test drive after replacing the Overflow valve and the Prefilter. So far I am very impressed, but I only went about 2 miles. After it sits all night and I fire it up cold will be the real test. The whole job went pretty smoothly. The only problem I ran into was trying to keep the new gasket on the Prefilter bowl in place, but a little rubber cement took care of it. Did find the heater bolt loose. I jumped on the throttle and released it immediately several times and it did not stall this time. Throttle response seems to be better, too. Will keep you posted. Thanks for all the help,
Mike