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Topic: gelled fuel? (Read 597 times) previous topic - next topic

gelled fuel?

Good evening everybody.  Just got back from five months in Phoenix AZ.  Decided to try and start the U300 and it ran for a minute or so and then quit and wouldn't restart.  It was very cold here in north Idaho this winter where it was stored, but in the 40's today.  My question is could the fuel have gelled since it was summer fuel?  If so, would it be ok to  use a diesel space heater to warm up the engine bay area, and would that reliquify the diesel?  Should I take a fuel filter off and check?  I should say it is a 93 6V92 Detroit Diesel.  If the filter is empty and I refill it, would it airlock? 

Re: gelled fuel?

Reply #1 –
Quote from: rinron –
Good evening everybody.  Just got back from five months in Phoenix AZ.  Decided to try and start the U300 and it ran for a minute or so and then quit and wouldn't restart.  It was very cold here in north Idaho this winter where it was stored, but in the 40's today.  My question is could the fuel have gelled since it was summer fuel?  If so, would it be ok to  use a diesel space heater to warm up the engine bay area, and would that reliquify the diesel?  Should I take a fuel filter off and check?  I should say it is a 93 6V92 Detroit Diesel.  If the filter is empty and I refill it, would it airlock?

Warmer temps should help to ungel as well as certain additives available at most auto stores.

Are you able to run your generator? If the generator runs, you may just need new filters.

Re: gelled fuel?

Reply #2 –
If it ran and then quit I'd put my money on algae in the fuel clogging the filters. Fingers crossed that Zach's suggestions yields positive results.

Re: gelled fuel?

Reply #3 –
Power Service Diesel 911 and let it sit for a couple of hours. Start right up!
Doubt fuel filter is empty.

Re: gelled fuel?

Reply #4 –
If you have a block heater turn it on for a couple of hrs, pre fill your filters and start it. When they are cold three cyls will fire off and as the it warms up the other three will fire. It sounds ruff and then smooths out.

Re: gelled fuel?

Reply #5 –
Quote from: rinron –
It was very cold here in north Idaho this winter where it was stored, but in the 40's today. 
My question is could the fuel have gelled since it was summer fuel? 
If so, would it be ok to  use a diesel space heater to warm up the engine bay area,
<Bingo>--and would that reliquify the diesel? 
Regrading Bingo,
What happens when diesel fuel "gels" in extreme cold does not involve the entire tank of fuel turning into an aspic or gelatin.
mold.  The paraffin wax dissolved in the diesel fuel turns into flakes and ultimately plugs up the fuel filters.  Upon a rise in temperature or with the addition of cold weather diesel additives these flakes re-dissolve.  And we're talking about a 10ºF "Cloud Point" for paraffin flakes to form in summer diesel.

Re: gelled fuel?

Reply #6 –
If gelled, your fuel will slowly return to normal as the temp goes up.  Sitting in an unheated building along with the insulated compartment where the fuel tank is will work against you on warming up.  Can you see into the tank at all with a flashlight?  If the fuel doesn't look cloudy, gelling likely isn't your problem. 

Re: gelled fuel?

Reply #7 –
As it started and ran for a minute so it isn't too cold. I would take your filter off and cut
it apart and you can find out a lot doing that. My experience with Detroit engines is the
fuel filter has to be prefilled or it won't start but as haven't worked on the 92 series it
might be different.

Re: gelled fuel?

Reply #8 –
Our coaches are the same year with the same engine except yours is 4 feet longer.

Check tank with flashlight for signs of jelling.

Putting my $$ on air. Algae likes warm weather plus your fuel tank does not breathe as the temperature changes so very little chance moisture can get into the tank. Algae loves the water/diesel interface to grow. But, no matter how clean your tank is, it only takes the next fueling to introduce algae.

Are you familiar with the diesel hand pump mounted on the frame rail down on the right side as you look in the engine door? If not, it's used to fill the filters. You push in and turn the black handle and then start pumping. It does have a couple of O rings that were shot on ours. I took the little pump off and installed new O rings from NAPA. Only $0.10/ea. The spring loaded return valve is located close by. Ours had a crack and was letting air in so I replaced it.

I also put a pressure gauge on the primary filter so I can watch pressure as I pump. I also installed a pressure gauge on the discharge side of the secondary filter. The discharge pressure should be about 35 psi. The Detroit lift pump is pretty bulletproof so it's last on the list of suspects.

So, to fill the system or even check for air, I take a bright flashlight and see if there is anything in the clear plastic bottom on the primary filter. It has a drain. If clear, loosen the secondary filter a turn, put a plastic bag on the filter and use the hand pump until no more bubbles come out, (you should have at least a couple of each on board). Install the new primary and bottom plastic sight glass and tighten. Install the new secondary filter but leave it a turn loose. Repeat the procedure I outlined above. It will take a while with the hand pump to fill both filters until only diesel comes out of the secondary filter. Tighten ONLY AS THE INSTRUCTIONS SAY ON THE SIDE OF THE FILTER. Keep pumping after the hand pump becomes more difficult as you want to try and push any remaining air back past the relief valve and back to the tank.

Don't use the starter motor for more than 10 seconds and then let it cool for a couple of minutes. Don't use the starter motor to fill the new filters.

See photos below.

Pierce

Re: gelled fuel?

Reply #9 –
Thanks for all the replies and ideas, guys.  I started by putting my diesel-fired space heater on the tailgate of my pickup and aiming it towards the engine.  I then put small electric heaters on the fuel filters.  I turned on the block heater and waited a couple hours.  It started almost right away with some cranking.  So all is golden now, and I could back it out of the barn where I could get the bay doors open.  Once again, thanks for all the ideas.  Ron

Re: gelled fuel?

Reply #10 –
Great! Now, get rid of the phony "block" heater that is on the thermostat housing and put the correct one under the AC Compressor where Detroit normally puts the block heaters. You do have to drain the cooling system to do it. Best is a remote heater in the engine compartment with hoses to the head/block or even a magnetic heater. The OEM block heater only heats the crossover pipe. Detroit's don't. have a heated screen in the intake plus the turbo engines have a 3 point lower compression ratio so can be hard to start without warming things a bit.

Pierce
 

Re: gelled fuel?

Reply #11 –
As being a farmer, I have run several diesel engines in the winter time, in early spring, in late fall. I'm glad you figured out what was the problem.My two cents is put some Hot Shot anti-gel in it, and it will help to get water out ,and lower your diesel gel temperature  so it runs in cooler weather. Over the years I have found ' Hot Shot' to be better than the rest of the anti-gels. Power service is the one that Cummings diesel's back. Good luck.