Changing out the FMU

[Bullseye240]

I have been thinking about replacing my FMU with a fuel/water seperator and spin on filter same as on a class 8 over-the-road truck and was wondering if anyone here had done the same and what results they had. I have seen the feed the beast mod and think its a lot of work for a little gain. If you could replace the FMU with an esaier to service system it would make more sense to me.

 

[Turbine Doc]

FMU ???? what do you mean by that

I have 10 mic racor spin on filter with aqua block element prior to the lift pump, been there 5 years never had a wif or dead lift pump issue since,

 

[chi2]

I think that he might mean "fuel manager unit", aka "fuel filter manager" (FFM; what the manual calls them at least :smile5 for our beloved 6.5's. Just a guess.

TD: given that you have the 10 micron Racor, do you ever have to change the fuel filter in the stock FFM, or does the Racor do all the work removing impurities? It could be that your fuel (post-Racor) is cleaner than a crystal geyser in Yosemite.

I don't know what micron level our stock fuel filters are rated, and I wondered if the the stock fuel filter is still catching finer particles than your Racor (i.e. under 10 microns).

Jon

 

[Turbine Doc]

I never change unless needed now, when my vac switch goes high telling me it's blocked, got about 3 years on em now, tank sock is 70 micron, 19 micron is my racor, the into my factory fuel manager, which is 5 micron nominal, don't delete it as it has a WIF sensor in it as well as a heater, plus nifty place to add larger fittings for the FTB mod. The Racor has clear bottom on it and I can see if any water is present, some day I'll add WIF to it also, but haven't drained much water from it ever.

 

[Bullseye240]

Yes I'm refering to the fuel manager. I was looking at the feed the beast mod and like I said it looks like a lot of work for little gain when you could just replace the whole unit with better filter and water seperator and install a fuel pressure rail with a regulator to keep the pressure where it needs to be with plenty of flow. Turbune Doc, how hard is it to get your lift pump to self prime when you change out the prefilter you installed? I have been having stumbling under light acceleration lately and wonder if its running out of fuel because it takes a min to regain its driveability when it does it. It also has died several times latley after an extended idle and attempt to accelerate. Might be a PMD related issue and I have one in route but if that doesn't fix it then I think I might try something fuel related like replacing the system from the lift pump forward.

 

[Turbine Doc]

Yes I'm refering to the fuel manager. I was looking at the feed the beast mod and like I said it looks like a lot of work for little gain when you could just replace the whole unit with better filter and water seperator and install a fuel pressure rail with a regulator to keep the pressure where it needs to be with plenty of flow. Turbune Doc, how hard is it to get your lift pump to self prime when you change out the prefilter you installed? I have been having stumbling under light acceleration lately and wonder if its running out of fuel because it takes a min to regain its driveability when it does it. It also has died several times latley after an extended idle and attempt to accelerate. Might be a PMD related issue and I have one in route but if that doesn't fix it then I think I might try something fuel related like replacing the system from the lift pump forward.

Racor 660 I used for frame filter has priming bulb built into it, if using a OEM lift they can and often do quit pumping, purr like crazy but don't move fuel, you could single filter and not do FTB but then you lose WIF & heating unless your new single filter has it, I went with (2) a 10 mic to protect the pump, and 5 to protect the engine, a single 2 micron is not way to go, I don't have emails here but Racor, Stanadyne, Wix, Baldwin all say single 2 mic filtration is a mistake, better overall protection had by tiered protection.

more here http://dieseltowingresource.com/showthread.php?t=53 post 8 is where I added some thoughts

 

[Bullseye240]

Thanks Turbine Doc, I'll look into it. I really need to get a fuel pressure guage. Any ideas on who makes one that has an isolater so it can safely be mounted inside the cab? Thanks for the help.

 

[packratt]

Pick up one of the electric fuel pressure gauges. Best buy I've found is a Stewart Warner at Napa for around $85. The Autometer and VDOs are considerably more.

 

[Bullseye240]

Thanks again Turbine Doc. I'll probably pick up a spare lift pump and when I get home at the families house for thanksgiving I'll add a prefilter and a couple of other things.
thanks again for the help.