I have a 1992 Dodge D250 that has been modified to run on waste veggie oil. It has run like a champ for years that way, pulling a 30' streamline trailer that is my catering kitchen (Headwaterscafe.com).
Until... I changed the veggie oil filter and maybe introduced some gunk into the system. I have had the following:
Diesel fuel filter
Lift Pump
New Injectors
They pulled the injection pump off and rebuilt it
It runs and drives now, but under a load it bogs down and smokes.

Any ideas would be much appreciated. They are just trying to get it to run on diesel now, the veggie system has been bypassed. The truck has been modified, but worked great until I changed the veggie oil filter.

It's been in the shop for a week and could it be...
Fuel shutoff solenoid?
Injection pump?
Seems to be a fuel supply problem or compression problem.

They still have it, but after having the injection pump rebuilt and reinstalled, it still does not run good and I have a catering gig for a movie starting up in a week that I NEED my truck for.

Any help is GREATLY appreciated.

Jason

 

Air restriction?

 

Maybe a partial plugged fuel line ?or a cracked fuel line sucking air ?

 

i ran veg oil for years.never any problem.maybe just lucky!a friend, like me ran about 90% veg oil in warm weather.he had a piece of carbon break off the head or piston and score a liner.i know veg oil tends to coke things up a little. if this is the case you would see excessive blow by( that is kind of extreme,only heard of that problem one time).also sometimes veg oil will soften and deterioate some rubber fuel hose.sometimes they look good on the outside but collapse on the inside.don't forget that mesh filter inside the fuel tank on the suction line.if your running real crap oil it can clog.

 

Thanks so much for the ideas. It's at a shop I have never used before and already been wuoted $3,700.00 for the new injectors, injection pump and front brake pads. They did not turn the rotors, just put new brake pads on the front. The original quote was $2,900 for new injectors and rebuilt injection pump, and then it went to $3,700 because they had to spend an additional hour to get the injectors off and replace the brake pads on front.
What does anyone think? I feel like they should fix my truck at this point and get it running good for 3,700 max and not charge me any more because maybe it's a clogged fuel line somewhere and it didn't even need an injection pump.
The injection pump place said it didn't look too bad, more varnish than normal but they had seen worse, indicating that I can keep burning veggie oil if I want to. There is risk to it, but it saves money and it's just too cool. I guess $3,700 buys a lot of fuel though, so the jury is still out on that one.

ANY help anyone can give is much appreciated. Also advice on how to deal with the shop that has my truck because I need it for work next week or it's renting a truck for $400 a week which sucks. I know air leaks can be hard to find, maybe it's that.

Also, is there a way to test the pressure of the fuel going into the engine with a load placed on the engine or just at idle.

Million thanks on this thanksgiving!!

 

I don't know what the problem is, but, I am pretty sure that the shop is taking you for a ride. I would go get the truck. Fill out your signature with location and there might be a member nearby that can help, good luck...Mark

 

Why do you think they are taking me for a ride?

 

Because 1200 dollars for 50 dollars worth of front pads and an hour of labor. Also, any shop worth it's salt would diagnose the problem before giving a hard quote. I am not much of a diesel mechanic and I was able to replace my injector pump with a 750 dollar remanufactured unit (at the time) in about 4 hours. These first gen Cummins engines are pretty simple and fairly easy to diagnose. It is the later, more complicated, computer controlled ones become a little harder. The other problem is that the mechanics that worked on these a lot have moved on. If it won't run on waste oil or diesel, it is probably a problem in the tank, various filters or fuel supply or return lines. This is just my opinion, but I would run away fast...Mark

 

did they supply the Jar or did you because it sure sound's like you are getting Shafted .

 

What did they set your timing at?

 

If it ran good until you changed the filter, you have a blockage after that filter. Also what color is the smoke?

 

I have often heard that when you run veggie oil,or wmo if you have any crud in the tank, it loosens it up and can clog a line or foul an injector. Best of luck!

 

Your timing sounds like it is too retarded. Mine did that when I didn't tighten up the bolts after the headgasket replacement. Goodish power up to around 2200-2500 rpms and it would pop.

 

they said they advanced the timing on it, but I still think it might be a clog or partially blocked fuel line somewhere. It is a two tank conversion so the veggie and diesel filters and tanks are separate and the fuel hoses are mostly parker super flex rated for biodiesel, but it could be a bad fuel hose.
But what are you supposed to do, start at the fuel tanks and replace all hoses from there to injection pump? How long would this take and where would the diagnosis start?

 

how do you test for an air restriction and where would it be?where would you start?