Rough Idle, Blue Smoke, Runs Better over 1/4 Tank???
 

Alright, its my uncle's truck, and he hauls a lot of horses... Truck is a 06 3500 4x4 Auto. Its maintained fairly well, new fuel filter 3 weeks ago, all stock besides a Quad M^3. Here's the problem: Turn the truck on, and it runs real rough, a lot of lope to it, and it smokes blue pretty bad. It runs rough, low power and the poor idle worst when the fuel level is below 1/4 tank... If its over that its not nearly as bad. The truck has 235K miles on it (like I said, it hauls a lot).

I'm going to go ahead and replace the lift-pump with a PPE Lift Pump, and use a new draw straw for the install to bypass the stock in-tank pump.

Anyone think it could be something else? Should I not bother with the lift pump? It's not going to get tuned up anytime soon, he say's it has plenty of power as it is for hauling horses, so performance isn't an interest, and he hates guages that aren't factory installed, especially pillar guages, so I can't throw on a whole host of dials to monitor parameters...

sounds like a lift pump to me. Maybe go with an Air Dog. just my $.02

call Tony at Mighty Diesel, he got my Air Dog here the with in 14 hours of me calling him, if you need it that quick

Yes, I also just ordered an air dog and injectors from Tony this morning and they will be here tomorrow :5:

Well I already have the PPE pump off a buddies old build, it cost me nothing, and from what I've seen and heard about them it should work just fine for me.

Now the big question... Is the factory lift pump a bypass unit, or should I put in a Draw Straw (I already ordered one).

I think you are asking if you can suck fuel through the OEM in tank pump... I say, no. So you would want the new draw straw unless you want to take out the OEM pump. Either way you will be pulling the tank off the truck. It isn't that bad of a job at all. The only hard part I found was getting the fuel lines disconnected from the sending unit (On top of the tank). It helps a lot to pull the left rear tire to be able to get in there. Yell if you need any more help. I have pulled a few of these tanks (We are talking about a Cummins here, aren't we?).
I plan on adding an external lift pump and just turning off my OEM lift pump (I already installed a 1/2" draw straw!). This way I can turn the OEM back on if my external dies out on the road somewhere to get me back in!

Actually on my other ford truck (dual tanks,) im able to suck fuel through the original fuel pump because that went bad. not sure about dodge, but i think you can. blue smoke sounds like rings, which it really shouldnt need yet but with this new low sulfur diesel shit you never know. :humm:

No... It ain't rings, compression is good. Keystone rings rarely go bad unless they break.

I've dropped a few of these tanks, actually, more than a few... I just wasn't sure if the stock pump has a bypass in it. Apparently it doesn't, which is alright since I already ordered a Draw Straw.