[tonyz]

I'm trying to avoid getting grease in the diesel filter so it looks like I need two solenoids for fuel. I need one before the lift pump to select grease or diesel and then one after the lift pump to bypass the stock filter when I'm pumping grease.

Is this how others have plumbed? There's no room in my engine compartment to put my grease filter so it's going to be at the tank but I'm concerned about having a mechanical pump with no filtration going directly to the IP. If the pump fails or gives off a shaving or two it could really cause some damage to my IP or injectors.

Anyone have some good advice? Will a 40 micron supplemental inline filter keep out the nasties from the pump?

 

[mm0015]

You could probably do what you describe using two fuel line switches, but you may be better off to run a seperate fuel line / pump for your WVO. This allows you to greatly reduce your purge time, sine you only need to purge the shared components, which in this case would be just the fuel rails and a very small section of shared fittings. You could probably use a switch in the engine to accomplish this, but you could also use check-valves. Search on FN74 on this forum to see the design that one of the members on here designed, and seems to work very well.

As far as you inline filter, I really am not usre. I am actually debating the same thing for my own setup, as my filter was also way too large for the engine compartment, besides the fact that it is actually designed to be on the suction side of the pump anyways.

 

[tonyz]

If set up a separate fuel system then the mech pump will just run with no pressure release on the diesel side while I'm running veggie. Won't it pop?

 

[mm0015]

I don;t know very much about the earlier design's but the later models with the elctric pump will just return all the #2 back to the tank through the factory fuel return. This is similiar as to when the engine is idling, since so little fuel is used at idle.

 

[tonyz]

The '90 doesn't have an electric fuel pump it has a mechanical pump. I'm just concerned about over loading or damaging that pump.

 

[mm0015]

Doesn’t the mechanical pump still have a fuel return? How does the system function at idle, when the engine consumes very little fuel? I really don’t know though.

 

[tonyz]

The mech pump is tied to engine revolutions. When the engine isn't reving much it isn't pumping much.

Here is a diagram of how I think I have to plumb it. The problem with this system is I'm going to need some kind of small secondary filter after the mech pump on the grease side of the loop.

http://wowway.com/~azara/image/ford250.gif

 

[biosdude]

I saw banshee350longrod's setup this weekend on his '89. He replumbed the fuel system like the following crappy text diagram:

diesel ----> filter ---+
..........................6 port ---> lift pump ---> IP ---> fuel rail
veggie ----> filter ---+

He placed the stock filter before the lift pump and placed a 6 port to select fuel before it went into the lift pump. I don't think he had an inline filter between the lift pump and the IP. Since both fuels are already filtered before entering the lift pump, I was planning on just adding in one of those see-thru inline filters between the lift pump & the IP.

Sorry about the text graphic, looks fine in preview /ubbthreads/images/graemlins/confused.gif

 

[tonyz]

Thanks for the input guys. I'm going with the dual electric pump system. I'm going to bypass and block off my mech pump. After reading here I see that a chevy big block plate will work.

I intend to T in the grease and grease return after my stock fuel filter.