Need help - Truck barely runs in zero temps!

[KingNuzz]

My '93 6.5 5-speed is barely running now that we've had over a week of temps between -18 and +10 F. This is my first full winter with a diesel truck, so I'm looking for guidance. Hope I haven't done anything too dumb.

Truck started losing power this last Monday, and stalled once. On Tuesday, I limped home with less & less power and speed on my 23-mile commute that night with temp around 5 degrees. If I kept the revs up around 2500 RPM, I could keep rolling but felt like it'd stall out if I didn't feather the throttle. 45-50 MPH max in 4th gear. No acceleration or torque. It was going in for an oil change the next day so I had the garage change the fuel filter as a first step. It sat for a couple of days, then they kept it inside overnight last night before changing oil and filter. I picked it up tonight cold, with temp. around 10 degrees. I cycled the glow plugs twice and it started OK, running a little rough but smoothing out. After 4 - 5 minute warm-up, I started home. Again, no power. Needed creeper gear to get the truck moving. It stalled a couple of times. I warmed it up for 10 more minutes and limped home, with some power but not much. Does this sound like gelling in the tank or lines?

The big unknown to seems to be fuel. I was running biodiesel over the summer into the fall, with no apparent problems. At the beginning of December, I'd switched over to around 50% biodiesel / 50% regular fuel, plus Power Service Arctic Express. By late December, I'd gone to 100% regular diesel, with additives. During this time I'd had the "Water in Fuel" light come on about 6 to 8 times. Each time that happened, I drained the fuel system with the water valve at the front of the engine. I've kept the tank full and changed the fuel filter once in December. The truck ran OK until the cold weather hit the Northeast. I'm wondering if I have mystery gunk in the bottom of my tank that's causing problems. Any remaining biodiesel (or petro-diesel sludge) that didn't mix into the fuel would be at the bottom of the tank because it's heavier than regular diesel. Is the truck's fuel pickup at the bottom of the tank or is it a floating pickup? Could it be something else?

What do you suggest?

John

[Barry Nave]

Water in fuel light coming on that many times is not good :eek: Water at the bottom of take will still frezzzzz though manly add to the gelly state. Got to get that water out and the tank clean. The water is still getting to the filter and buy now the new filter is wasted. The fuel addtive is helping to mix the water with fuel and it is trying to burn it but it is just to cold so your not just burning diesel.
Your fuel system is a mess :eek: Better clean the system up and start over :D

[cruzer]

KingNuzz, Is it smoking when sluggish to drive?
If so what color smoke? I also agree fuel sys sounds like it's a mess.

[KingNuzz]

You're right ,the fuel system is a mess. I'm going to get the tank and fuel lines cleaned out as a baseline before doing anything else. The residual biodiesel could be raising the gel point bigtime if it's not mixing well with the regular diesel; Bio on its own gels solid around 32 F. I suspect the diesel / bio mix settles into layers enough if the truck isn't driven constantly and the fuel mix circulated and kept warm. I don't know how much heat the truck puts into the fuel as it recirculates it.

If I'm going to burn even some biodiesel during the winter, I wonder if arctic style heated fuel lines and tank heater would be a good solution even if $$$. Do you know anyone who sells or makes this cold weather fit-up for a 6.5 or any other 3/4 to 1-ton truck??

I haven't checked for smoke while driving. When it starts, I seem to get fairly "normal" bluish diesel smoke for several minutes.

[MTTwister]

So, is the Bio-Diesel worth all this hassle?

In cold weather, you also need some #1 diesel in there, or hope your getting a good 50/50 blend at the pump.

Cleaning out the tank and lines sounds like a real PITA. Good Luck.

[KingNuzz]

Yes, cleaning out the fuel system will be a major pain in the tail. Curious to see what comes out. At this point, I'd still say the bio is still worth the hassle. It's a type of high performance thing - having a big pickup that will haul and tow, yet that puts out less CO2 than a small car. Plus shifting at least some of the fuel source to American farmers. At least for now, I'm willing to put some of my own time and money out there. Few truck types are doing this, particularly with the 6.5 and 6.6.

Meanwhile, I'm ordering the Helms manuals, and looking into tank & line heating. If the Webb HotSTK works and is not to much $$$, I might go for it. Any ideas or thoughts?

[charliepeterson]

Dump the Bio Diesel!!

We tried that stuff as an experiment in Boston on the Transit Coaches. It failed big time!

The stuff gells up like syrup and when it did burn it burned with hot spots on the pistons. We lost a couple of Detroits with melted pistons. It plugged up the "Cats" also.

[KingNuzz]

Charlie-
Scary story! Did semi-gelled biodiesel get through the injection pump because of its lubricity then "blob out" through the injectors?

This does have me wondering about using biodiesel, particularly in cold weather. Questions:
- How long were you using bio? What percent?
- Were tanks and/or lines heated, or did they rely on blending and additives?
- What time of year did the fragged pistons happen?
- Were there any "warning signs" or were the melted pistons a sudden failure?
- How "high-tech" were the Detroit engines' fuel systems? Were they high pressure /tight tolerance, or older style (sort of like a '93 6.5)? Mechanical IP or electronic?
- Did they tear down engines and fuel systems to see what else happened?

Thanks,

John

[number two]

The fuel filter/manager has that temperature controlled fuel heater in it. I've often wondered how effective they are. I don't recall exactly how much current it draws,but it's something like 6 - 9 amps depending on temperature. Seems like it starts heating about 40F. That much amperage is almost like having a glow plug in the fuel filter. Seems like that would warm up the fuel and keep it flowing through the filter. Think yours is working?

[ucdavis]

The fuel "manager" runs about 100 watts IIRC, but it is atop the engine, so even though the fuel recirculates, when it gets as cold as you guys are dealing with, I'd bet the tank and return lines are re-cooling the return fuel to a steady state not much above ambient temp. If this stuff is gelling up on you, the fuel heater isn't going to add any value to mixing gelled w/heated fuel cuz the heat only lasts part way back to the tank. Best solution is to move to Florida and retire ;)

[dieselbegreat]

About your problem, I wouldn't jump to conclusions about the biodiesel so fast. Your Water in Fuel light coming on intermittantly several times, especially only under a load, doesn't necessarily mean water, but that something in your fuel is clogging your filter. I would think by now all the bio is gone and maybe you just have pumped summer or questionable fuel in your tank. Maybe check to see if the filter heater is working, run your fuel line tied against your heater hoses if possible, maybe install a small section of clear plastic line, keep an eye on your fuel pressure between the filter and the IP, and add some kero or Power Service 911 melting agent and see if that clears things up. Trucks with rear heaters could run extra coolant hose under their tanks to warm the fuel too if one has nothing better to do and a warm garage to do it in. tongue.gif

[ 01-21-2004, 05:39 PM: Message edited by: dieselbegreat ]