Fuel and filters - conclusions after the cold snap

[Mark Rinker]

For what its worth, here are my observations and conclusions after 6 seasons operating GM and Kubota (Bobcat) diesels parked outside through Minnesota winters, factoring in knowledge gained here.

The first 4 seasons with the 6.5s and Kubotas were no problem - prior to the biodiesel mandate. Last two seasons things have changed, Duramaxes and the Kubotas. (Fuel in common - not filters)
Its the bio-diesel, not the brand of filters. The last two plowing seasons have clearly shown problems on both trucks and skidders below -5F that live outdoors. Absolutely when temps fall under -10F. If you aren't pre-treated, parked inside, or both - you are very likely to have problems with the Duramax filters plugging, especially if they are late in their service life.
LB7s are more forgiving that LLYs or LBZs, simply because they don't limp out on you, they run until they fall on their face. Our '06 is annoying - it limps when the filter isn't even plugged, the rail pressure is just too low, limiting you to 2K rpm until the code is reset. Usually by 10-15 minutes of driving, the truck is warm enough underhood to solve its own problem. I have quit throwing filters at the 2006 - its better just to drive it through the limp, adding 911 which works like magic.
If you must park outside in -5 weather or below, PRETREAT the day before and get that fuel through the entire system before you shut down. (Obviously, plug in the trucks and run the winter fronts.) Once started, don't idle too long, you are better to get the truck moving and get the fuel circulating and the underhood temperature up quickly and simultaneously. My '06 LLY will limp out if left idling on a -10 or colder day after startup, from the low fuel rail pressure code alone.Oh, for a heated shop...someday.

[SoTxPollock]

You know your 02 LB7 has a fuel heater from the factory, I think they discountinued puting a fuel heater on later versions, perhaps GM should reconsider.

[DickWells]

Mark: Have you ever tried, or considered any after market pre-filter, lift pumps, warmers, or combinations of? Just wondering if you think they're worth a try. I was concerned about the fact that the DM uses the IP to lift fuel for itself, and I have read all the hooplah about the after-market stuff to avoid the percieved shortened life of that IP.
I was going to install a LP-filter before I went to Alaska last summer, but have never gotten to it. A fuel injection expert up in Wa warned me that adding a LP could starve my IP! Now that doesn't make sense to me, but who'm I but a hick Vermonter?
Your thoughts on this?
Thanks.
Dick Wells:)

[DmaxMaverick]

You know your 02 LB7 has a fuel heater from the factory, I think they discountinued puting a fuel heater on later versions, perhaps GM should reconsider.

The later models still have the fuel filter heater. It was the intake heater they messed with over the years.

[DmaxMaverick]

Mark: Have you ever tried, or considered any after market pre-filter, lift pumps, warmers, or combinations of? Just wondering if you think they're worth a try. I was concerned about the fact that the DM uses the IP to lift fuel for itself, and I have read all the hooplah about the after-market stuff to avoid the percieved shortened life of that IP.
I was going to install a LP-filter before I went to Alaska last summer, but have never gotten to it. A fuel injection expert up in Wa warned me that adding a LP could starve my IP! Now that doesn't make sense to me, but who'm I but a hick Vermonter?
Your thoughts on this?
Thanks.
Dick Wells:)


Any "fuel injection expert" that thinks adding a lift pump will starve the HP pump is no expert. Other descriptive titles come to mind, though.

[Mark Rinker]

I think an in-tank, or in-line fuel system heater would be the most effective. When the truck's block heater is plugged in, so is the fuel.

http://www.arctic-fox.com/

A lift pump might just provide the extra flow needed to keep the filter going until the underhood temps are up - especially with warm fuel. Maybe the '06 will get one this summer as an experiment. Would a 6.5L style pump work, mounted in the frame rail?

[gmctd]

Dunno what that 'expert' had in mind, but adding a lift pump can indeed 'starve' the CP3 - can't hurt the CP3, but will cause engine stop - the aux lift pump must be flow-thru when failed, as are the 6.5 pumps, and the '05-'06 Dodge in-tank lift pump - earlier versions would cause engine shutdown upon fail, even tho the CP3 can draw 20"HG vacuum on the input

Is a good test to verify this: prior to installation (hopefully!):eek:, connect the outlet fitting and suitable tubing, pretend it's a straw and you're trying to sip a thick milkshake, or rootbeer float - if you cannot get airflow, it is not draw-thru - can also put a vacuum guage on the inlet side to check the actual break-point (and your prowess with a milkshake!)

[ISEEDIT]

For what its worth, here are my observations and conclusions after 6 seasons operating GM and Kubota (Bobcat) diesels parked outside through Minnesota winters, factoring in knowledge gained here.
If you aren't pre-treated, parked inside, or both - you are very likely to have problems with the Duramax filters plugging, especially if they are late in their service life.
adding 911 which works like magic.


FWIW - A couple flags stood out in your post. I've learned my lesson early on with fuel / gelling problems. This is what works for me -
Pre-treating fuel. - Minnesota, cold, pre-treating and or #1 for those that don't treat #2, is like grabbing the coat and long underware. If you don't want problems, just do it to be prepared. A person can put too much additive in fuel and reverse the effects of the additive. I read your post as you may not always pretreat or pretreat early enough?
Diesel contains water - your use of 911 would be a clue that there is more moisture / water in your fuels / filters then "normal" in the fuel . Don't know what's up there, but it shouldn't be neccessary to have to treat w/911 with normal fuel conditioner pre-treats and Minnesota winter blend fuels. I'd be looking for additional source of moisture / water infiltration when filling up or around the fuel caps when moving snow. If 911 works - keep at it. Not for me though -
Most problems of gelling fuel is acturally moisture / water in the filters from poor serviceing of filters. Change filters in the late fall and keeping fresh water sperators and filters on bulk tanks makes all the difference of a down vehicle and a running vehicle in extreme cold. No pre filters on bulk tanks and a guy is just asking for problems. Given your experence, I'm sure you have a good maintinance program . . .
Nothing worst then a stalled vehicle, tractors, skidsteers in cold. Knocking on wood here, I don't have those problems on the farm, but do have a rigorous routine for fuel and filter maintinance. I keep engine compartment of the tractors /skidsteer covered, like the front of our DMax trks. It keeps what warmth there is there to help keep the water/fuel from freezing. I make sure I get quality fuel from Beaudry, and haven't had the problems you mention (currently have B5 winter blend with additive). These things work for me - hope you don't have downed vehicles in any weather !

[mhagie]

I have a 6.5 pump with the Kennedy harness on my 02, works like a champ.
It won't pump enough fuel for high performance tunes etc, but all I have is the Edge EZ so no problem there.
Merle

[Kennedy]

Any "fuel injection expert" that thinks adding a lift pump will starve the HP pump is no expert. Other descriptive titles come to mind, though.


Actually it could. Adding a mechanical gear type pump or rotary vane can do just that if it ceases to operate. The Dmax can pull some NASTY vacuum and idle, but not run worth beans if this happens. This is why my KD pumps are centrifugal.

The pre CR 24v Cummins has a rotary vane that can and does cause their IP to fail.

[DmaxMaverick]

Just so we're on the same page....

You/they would install a pump that doesn't work?:)

A positive displacement pump would be a poor choice for lifting fuel. It wasn't part of the discussion. Of course, a positive displacement pump would not allow fuel to pass if it isn't operating. Not only that, it would require a pressure regulator (relief valve) and additional plumbing, including a method to bypass. Is this an option someone should consider? I don't think so. A centrifugal, pulse (solenoid), or rotary plunger pump is an obvious necessity. They will all pass fuel when idle, by design. Sorry I didn't make that clear.

There may be a need for a positive displacement pump for specific applications. For the needs specific to this discussion, it would be a poor choice.

[Kennedy]

Many of the popular fuel pumps for that gasser crowd are being tried on the Dmax. Most of these are gear, gerotor, and vane type. Most of these pumps have a short lifespan pumping diesel. When they stop, it puts a pretty big load on the CP3. Thankfully the CP3 is like that girl you used to know who could suck a golf ball through a garden hose. It keeps running, but at reduced power, sometimes no more than idle...

[cabletech]

A lift pump might just provide the extra flow needed to keep the filter going until the underhood temps are up - especially with warm fuel. Maybe the '06 will get one this summer as an experiment. Would a 6.5L style pump work, mounted in the frame rail?


I added one of JKs magnetic lift pumps to my 06 and haven't had a gelling problem since (without additives). I think part of the problem with the Dmax is that fuel is pulled through the filter and you arn't using the whole filter surface area (easier to plug). What led me to this is my 95 has never had a gelling problem and my 06 has with fuel from the same place.

Jay

[carco]

I installed a 6.5L pump to push through the large CAT 2 micron prefilter on to the GM stock filter, has worked very good for nearly 40,000 miles. bob..............