ozo57

Just got this truck, 93 w250. Drove it home with out much issue (only a few miles down the road). Replaced all components of rear brakes and fuel filter and now when I start it it runs fine at a idle but when I rev it up there are large clouds of white smoke. This would be unburnt fuel form what I know. I have read about a return fuel valve, where is this? how can it be checked? What are some other things I should look into?

Took a video of what the truck is doing "http://www.youtube.com/watch?v=-F39xXaGLh8", any help would be greatly appreciated.

Thanks, Arlow

JBradley500

http://www.youtube.com/watch?v=-F39xXaGLh8

heres a direct link for anyone whos not that good at that stuff.

Onemoparnut

did you have any trouble getting it running after the fuel filter change?

benboonie

That looks more blue then white to me. Usually white smoke means some type of water vapors.,ie antifreeze/water. Blue usually shows that oils is being burnt. Black or dark smoke usually means fuel in excess. Does it stay that way? Not sure were your from but condensation is natural. If it stayed that way will driving even after warm up to operating temp I would worry. Remember metal does shrink when cold. IE gentle til operating temp. If it is fine at operating temp I would not worry that much.

But thats my 2 cents. I hope you get more ideas to help ease your mind.

jimbo486

I see in your sig that it has PODs and they have a pop pressure of 260 bar which is 15 bar above stock injector pop pressure (245) and what's comfortable for the pump. Having a higher pop pressure can actually retard timing a bit. With that said, it's possible the timing has been advanced to compensate for it. Maybe a little too much but the pump doesn't look to be too close to the head.

White smoke could be a symptom of excessive (advanced) timing but usually only present in the lower RPM range. It's normal for them to have a bit of white smoke while they're cold due to the advanced timing from the KSB. However, timing should return to stock after intake air temperatures reach 90 degs. which doesn't take very long. As benboonie asked, does it continue to do this after having been warmed up? If so, the KSB is receiving 12 volts when it shouldn't be which would allow for even more timing advance. Try unplugging the KSB and see if the smoke continues. I see a tinge of blue in the smoke though too.

The return line "valve" is actually a banjo bolt with a small orifice to create a restriction. It's on the backside of the pump. Below the AFC housing and above the hydraulic head of the pump. You'll see a small rubber tube on the AFC housing, look just below that and you should see the return line and banjo bolt. A plugged return line shouldn't cause any white or blue-ish smoke, though.

ozo57

Thanks for the quick replies.

The video was filmed when the truck was at operating temp. I had no problem starting the truck after I replaced the fuel filter. The filter was filled with injector cleaner plus a bit of karo as I did not have enough cleaner to fill the filter. The smoke does not clear up fully when held at a steady rev and anything over a idle the motor shakes and shudders bad.

I have read a little about the KSB but I'm not quite clear where it is located or what it stands for? I think it helps heat the air in the intake but this should not have been a factor as the truck was running at temp.

I did have to drop the tank to replace the rear brake line. Is there anything that could have been fouled up at this point?

I have to give the truck a little tap of the petal to start, is this symptom of a setting that may be off as the truck idles fine after that point?

Thanks so much, Arlow

G1625S

Truck was at operating temp meaning that the t-stat was open and the truck had been driven for at least 10 miles? Since you mentioned dropping the tank, I would have to guess that somewhere a line got cut kinked or otherwise abused to the point of letting air into the system. A simple way to check this theory is to plumb a known good fuel source (gerry can with clean diesel and a new line plumbed to the lift pump) and see if the problem persists.

ozo57

G1625S,
I can see how easy it could be to get a line pinched or cut. What would be the reason for the smoke?

Air gets in the line, which means less fuel gets into the clyinder. Would this not raise the temp in the cylinder? as more fuel would cool the cylinder down? I must have this all messed up?????

Thanks again, Arlow

G1625S

The VE is a pretty darn robust pump...but, to perform porperly, it relies on a consistant air-free fuel supply to do its job. Your mention of having to apply some throttle to get the engine to fire is what got my attention. One should almost never have to apply throttle to get a ve-pumped engine to fire up-that's the first sign of a fuel supply issue. The second is excessive smoke

ebteckx

ya know, my buddies truck did the same thing, then it started doing that even at an idle. He had a leaky injector. Just something to think about. I havent had this experience so I havent had to diag it myself but thats what was happening to him.

ozo57

So whats the best way to go about replacing the fuel line? Do you just buy some fuel line and splice/plumb it in on your own? or do you buy the factory line?

If I make my own lines, what size should they be and what type of material should I look for? I don't plan of going to wild with mods but who knows what the future holds. I would guess the stock lines would flow well enough but is there any reason to move to a bigger size?

I know it's a million questions, just psyched to have these trucks and can't wait to get them on the road.

Thanks, Arlow

Richie O

Was the truck stone cold? A cold engine will do that.

ozo57

No the truck had been running about 10 min and the temp gauge was reading right in the normal zone of operating temp.

G1625S

Put some regulated air (5psi or less) to the fuel tank and have someone else crawl all around the fuel lines to listen for air leaks and look for fuel drips. Many times, a line will be compromised enough to draw air while the engine is off, but not compromised enough to leak fuel.

TLRMAN

Door #3 for leaking injector or injectors ....Pull them and pop them..