Hey guys...recently I got about 10 gallons of bad fuel in my 99 Cummins. The "water in fuel" light came on and I drained it every time I drove it until the light went off. I figured I'd run that fuel out, then put better fuel in it.

A couple weeks later, it started running real sluggish and blowing light blue smoke for a few miles, then out of nowhere it would pick up and take off like normal. I pulled out from my driveway, held it to the floor and at the end of this few mile trek I was only going about 45 mph tops before it would pick back up. If the truck is shut off more than a few hours I have to go through that whole process all over again for a few miles.

I replaced the fuel filter and it continues to do this. I cleaned and re-oiled my K&N air filter with only slight improvement (but given thats its light blue smoke it sounds more like fuel starvation to me).

Do you know what could be the cause? The thing thats odd to me is it runs really sluggish for a few miles, then out of nowhere gets all the power back and pins your head back to the seat.

 

you can try to replace the lift pump, but you might have killed the vp44

 

If the water in fuel light was on and you kept running it, that's not good.

Usually by the time that light comes on, some damage has already been done and continuing to drive only makes it worse.

Water can't be compressed (well, not to any real extent) and when put through a high pressure pump (like the VP44) it basically turns it into a water jet.

The pump takes a beating due to the lack of lubrication and the injectors get hammered even worse.

 

hm....well, every time the water in fuel light came on i drained the separator til the light went off, the light would come on every time I started the truck and then go off after it was drained, I was trying to keep the water to a minimum....

is there any chance for recovery of the engine by putting additives (PSD or tranny fluid) in the fuel tank? or is this gonna cost me out the ***? lol

 

The problem isn't gonna be the engine itself, the water has no real effect on that. Hell, I run 3 stages of water and methanol injection in mine.

The problem is the damage the water does to your injection pump and injectors.

Just draining the water from the fuel canister isn't really effective. The only thing that's actually being seperated is the water that ISN'T emulsified in the fuel itself.

When you see the water in fuel light, you need to stop as soon as possible and DRAIN THE TANK.

The only way to know how much damage is REALLY done, is to pull the VP44 and the injectors and send them to someone like DDP or Industrial Injection or and authorized Bosch service center and get them tested.

 

Are you STILL on that tank of fuel?

 

no i've filled it with new fuel and it's slowly beginning to improve....more power at startup, less amount of time to get full power back after cold start, etc... after a couple miles I have full power and no problems at all. I'm hoping that the injectors maybe just need a good dose of PSD (which i put in today) and the truck will slowly improve back to normal. I'm not very mechanically inclined to even know where the VP44 or injectors are, but I can tell that there's an improvement since it first happened.

 

I just replaced the VP44 and that fixed the problem....so sluggish running while cold, cranking for more than 5 seconds to start (especially when engine is warm) and just low power overall.... and its ur VP44. I replaced it with a hot rod VP44 and added a Smarty programmer so now its got all kinds of power!!