WMO and WTF caused FSS failure
 

i've been running a mix of 60% mixed used oils and 40% diesel in my van, and it worked great for a long time - until last week.

i was driving down the highway when the engine shut off, so i pulled off the road and found the FSS had melted down and was smoking. i replaced the pump that night and drove for 3 days before having the exact same failure while driving down a different highway, same story but no visible signs of external damage. see this thread https://www.ford-trucks.com/forums/1...-down-why.html

the second time it failed, i removed the top cover of the IP instead of the whole thing, found the solenoid melted and heavily swollen, with gunk sticking to its end, gunk that resembles the black sludge you find in a transmission pan. as a result of this, i suspect that this gunk was getting through all my filters and sticking to the magnetized solenoid.

so for this experience, i'm seeing that filters alone are NOT good enough for a long-term WMO/WTF system, a centrifuge seems to be necessary.
i was also thinking that it might be good to install some very strong magnets to the exterior of fuel filters to catch any iron filings or similar debris at the filters. would that be good enough insurance, or is a centrifuge the only reliable way to get the fuel clean enough?

I seem to recall saying on here a few times that burning WMO is BAD!!!! its almost IMPOSSIBLE to get the carbon and who knows what else is in it out....

Save the WMO for the wood stove ;)

Diesel Rod

I only use small amounts of WMO in my truck. I do use a centrifuge and a 3 micron filter and have had no issues in 30k miles now.

From all ice heard, a centrifuge solves just about all the potential problems. People said that filters weren't good enough, no matter how fine. I figured it had worked fine this long and my pump still worked as well as the day it left the rebuilder, which wasn't all that good to start with (poor rebuild).
I've never heard of guys who use a centrifuge having any problem unless they try to approach 100% wmo, at which point they have trouble with the fuel being too thick.

I was quite disturbed by how much metal I found on that solenoid, and that was after only 3 days on that fuel mix, I'm gonna open up the first pump and see how bad it is inside

check your volt reading, for poss over volt, sorry to hear of your troubls have had no problems, with my fuel, just replaced glow controller as it gave out looked like an older unit. :-jammin

In hindsight, I'm remembering that the second unit to fail had a history of delayed shutdown, which suggests the fss was on its way out when I took that pump off back in January, so that failure appears to have been caused a long time ago and it's a coincidence that it failed 3 days after putting it back on.

I decided to add a few strong magnets to the outside bottom of the fuel tank and a few more top the outside of the filter, so any particles that may get past the filter media will be grabbed by the magnets. Having done so, I'm running my fuel mix again and it's running well

As for voltage, I haven't had any troubles with lights burning out or other signs of high voltage, but I haven't got a voltmeter on there to watch it either. I suspect it's fine.