[carolinabronco]

Hey all, heres what I got, other than a dead Bronco

Background: just took her on a 500 mile round trip to see some friends, and on my way from Wilmington to Raleigh, I stopped and picked up some B50 biodiesel. On the highway at about 65 I would intermittently lose power and have to shift down to 4th (plenty of power). It was about 19 that night so I figured my B50 was clouding. Got home to Raleigh and parked her and went to start the next weekend nothing but white smoke. Doesn't even try to catch. So I figured my filter was gooped up, changed it out nothing, but at 46 degrees outside clear cloud free biodiesel ran out. Oddly enough after changing my filter and trying to reprime the system, the plunger on the lift pump never felt like it built pressure, just went to the bottom of the throw with no resistance. Checked again this Thursday, still nothing but white smoke. Im not near the truck all the time so I'm trying to get some thoughts/experiences from people so Ill have some good ideas when I can work on it.....

Possible Problems I can think of::
1.) not getting 12v to the ve pump fuel solenoid (mine is the 12 to open style). or dead solinoid.
2.) Dead lift pump, biodiesel will eventually eat the nitrile rubber diaphragm in the older style lift pumps, my motor is a '92 (maybe why the pump feels like it has no resistance?) Would a dead lift pump cause a no start?
3.) Biodiesel, maybe but it ran clear in 46 degree weather, and I clanged the filter, I would think it would at least try to catch even with some bad fuel?

Thats really all Ive got any other ideas past experiences with no starts would be awesome! Post em up!

 

[averagef250]

It won't start with a dead lift pump. I'd pull the bleed plug or filter off and see if it pump fuel by hand or cranking.

 

[briney]

sometimes the engine will stop with the cam lobe for the lift pump at the top as well. does turning the motor help with the lift pump feel ? if not, it might be stuffed.

 

[mobetta]

I did bleed out my mercedes once by cracking open a line up front and using a shopvac on blow to pressurize the tank. wrapped a rag around the nozzle, and put it to the fuel fill. compressed air would work, too- just not too much...

also-while 19* is pretty cold, the tank should have been slightly warmed by returning fuel from the IP. maybe you developed an air leak in your fuel system- just small enough so as to not really kill it on the highway run, but while sitting the pump lost its prime?? just a shot in the dark...

 

[Machman]

It sounds like fuel gelling to me..

Had it happen to me at Thanksgiving. Similar temperatures, no biodiesel. Wild part was that I had started the truck, idled for 30 mins or so while loading, etc. and then took out of the driveway. I didn't make it 50 yards when she shut down. Attempts to restart were just like what you're describing. If I held the throttle down and cranked, it would catch and run, but attempts to idle shut it down, after 2x times like that, no run at all.

As CrewCab59 explained to me, and it agrees with what happened to me, once you have gel anywhere, just warming back up won't get rid of it in a lot of cases. You have to either purge it or get some anti-gel into it to dissolve the stuff.

To fix it I had to:

Confirm fuel solenoid operation by applying 12V and listening for the "thunk".

Change filter - filling it with anti-gel before fitting it back on the engine.

Put a couple quarts of anti-gel in the tank, then shake the truck.

Prime like crazy. And, FWIW, my lift pump doesn't ever really feel "firm" on the priming strokes. It works just fine, though. Crack the bleed on the banjo bolt, pump until it's clear stream from there, close it, prime a while longer. If you really want to be sure, pull the hose from the fuel return line and prime until that looks OK.

Crack an injector line loose at the injector and crank the engine. (Personally, I break all of them free and then re-tighten them just to make sure they're not going to fight me while cranking / running. Oh, and some rags are a REAL good idea here..) After you get a couple of gushes of fuel out there, close it off while still cranking. It may catch and run (maybe poorly..) when you do. If it doesn't, you may need to crack the others loose and purge those lines, as well. If it runs, but poorly, try purging the other injectors while it's running.

Personally, I think my gel adventure was brought on by getting fuel at a low-turnover station and got a slug of water with the fuel. When I re-fueled after that, I got it at a high-volume location (truckstop) and haven't had a problem in even colder temperatures.

And, if possible, might not hurt to plug it in for a few hours before you start in on this. Won't help with the gel, but will help take some strain off the starter..

 

[mooktank]

Get a piston lift pump and you can eliminate that possibility.

 

[carolinabronco]

A little resolution and a new question....

Hey All thought Id post up what I found.....
-popped the fuel line off at the lift pump and blew backwards (towards the tank) and it blew clear (heard bubbles in the tank) So I eliminated a problem from there back to the tank.......
-took off the banjo bolt at the head and tried to pump the pump to get any flow (I had put the suction end in a can of diesel at this point) and got zero flow.
-took the pump off and pumped it, magically the pressure and feel returned to it once it was off the truck, (after sticking my finger in the block I found that my cam lobe was all the way up....oops)
-BUT I plugged the pressure side of the pump with my fingers and listened to the suction side and heard a nice solid bubbly sounding leak.....:nuke:
-SOOO looks like I'm going to be getting a new piston style lift pump, thanks everyone for the help on this one, and I only have one more question in the article on TDR that is cited on this site a few times about piston pumps, is the fuel line part number that they cite the same for a 4bt (since that article was for a 6bt)???

Thanks guys!