A couple of hours

[guh2stroke]

Anyone live within a couple hours of St Augustine Fl that has decent knowledge of the fuel pump and system. Have taken truck to shop a couple of times and nobody there seems to know what's wrong with it. I'm not very mechanically inclined so it's hard for me to work on the truck myself. Truck was making about 40lbs of boost and now is making only about 15. I have pressurized the system and have found no leaks. The truck has a new lift pump a couple months ago.
It doesnt like to idle and when it does it's about 200 rpm lower than normal. I used to run veggie in it, thought maybe something was clogged. Changed the fuel filter to no avail. I would be more than happy to drive if someone is willing to help. Thanks guys, Alex

 

[PToombs]

Alex, check the little boost line that goes to the AFC. They are known to crack and/or break.

 

[guh2stroke]

Afc

Just checked it. She seems to be good. Everything little thing I check I get closer to finding it

 

[dpuckett]

If you were making 40psi before, the AFC hose crack will take you down to the mid-upper 20s.



Were you running STRAIGHT WVO, or was it distilled into diesel? If you were running straight veggie, you may have cooked your pump. The straight WVO is a LOT thicker than regular or bio diesel.



What is your fuel pressure?



If you were closer, I'd take a look at it for ya. I also know a good shop up the road from me.



Daniel

 

[guh2stroke]

Wvo

I was cutting it so it was thinner. I don't know what my fuel pressure is at. Thanks for the replys. I guess I'm gonna be looking for a pump with low miles or a rebuild, I don't know which would be better.

 

[paccool]

Before replacing the pump, I'd take a hard look at the AFC diaphram that the fuel cone mounts to. Make sure it hasn't split or gotten a small hole in it. Might also be a god time to see if the pin is leaking and the area below the diaphram hasn't filled up with fuel.



I think I'd also take the fuel line from the tank loose at the lift pump and blow back thru it to be sure it isn't plugged. The bio does a good job cleaning out old crap and something may be plugging the intake screen in the tank.



May not be this but I'd look to be sure.

 

[Greenleaf]

I would by-pass the fuel tank and suck from a clean container. You likely will not be able to drive it but you said it has problems simply running... .....



I would also by-pass the AFC and everything associated with it-drive it. Use a supply guage (one more reason to mount a gauge IN CAB)



Sounds like the pump innards are having issues but you MAY get luck with supply problem(s)



Then and only then pull the pump and look at the hydraulic head/sleeve etc.

 

[guh2stroke]

Thanks for the info guys. Alex

 

[PToombs]

Double check the lift pump. JLeonard had one go bad recently, was only on a few months. He found a chunk of black stuff in it, so he cut it open. Found one of the check valves went bye bye!

 

[guh2stroke]

Lift Pump

I'll definetly check it out. Thanks for the info.

 

[John Martines]

If you run straight and don't have it in a seperate tank with some type of heating element it won't really get thin enough even mixed, Any hydrogonated oil in there will globb up for sure. First thing is change you Fuel filter, second check the lift pump. Third check for coking at the injectors. We refine our veggie in stages, First let it settle and skim it, pump trough trash pump and screen, then heated and sent through 15 and 10 micron filters and in to a centrafuge. We used to only get 2500 out of a filter now we can go full life of filter. There's alot of sludge you can't see in the dirty oil and if you don't remove it, pumps ,filters and injectors will suffer.

 

[JLEONARD]

JLeonard had one go bad recently

Yes and it drove me crazy for a bit. Actually it was about 2 years old, maybe 25K miles on it.

My biggest clue to realizing it was the lift pump was that it was difficult to get fuel to pump manually when attempting to bleed the air out.



But the truck seemed to run fine normally except for the 3 or 4 times it suddenly just quit running. It never ran poorly or idled low or anything else. It would just up and die.