Fuel viscosity sensor?

[menarda]

Does our Duramax's have a fuel viscosity sensor, and if so where is it, and can it be defeated? I'm concerned about fuel filter lifespan, and hate to change filters because a sensor is measuring fuel viscosity and not the filtering capabilities of my filter. I recently had to change my filter when I ran into the ECM throwing a 'Lean Condition' and throtteling power down to a 2000rpm limit. Does anyone know what triggers the ECM to set this code, fuel pressure differential, fuel viscosity, and what I might be able to do to not get stuck again in 'limp home mode'?

:confused:

[Kennedy]

There is no viscosity sensor. The limp mode that you experienced was likely due to a plugged filter. If the pump cannot maintain rail psi within set parameters, it will trigger a DTC. It is also possible that your pump or regulator could be getting weak.

[DmaxMaverick]

Welcome to the Forums!

There is no way to get around filter life. It is all dependent on the quality of fuel going through it. Trying to "extend" filter life by an means, will diminish its filtering ability, and prevent the pump from maintaining desired/actual pressures. When a filter reaches its useful life, you can only replace it. That's it. There are better aftermarket filter options, including, a coarse prefilter, and/or a post fine filter.

JK has good advice, and also provides excellent filtering solutions.

[menarda]

Thanks for the quick replies guys. JK, by weak pump, I assume you mean a weak injector pump. Can the regulator be reprogrammed to a higher PSI with a typical aftermarket programmer? Would a lift pump help? The reason I ask about viscosity is because the fuel I'm using is a higher viscosity then #2 diesel. Not only am I new to diesels but it looks like I'm using a fuel not many people in the forum have experience with yet.

[DmaxMaverick]

The fuel rail pressure can be increased with a Tech II, or aftermarket mod, such as the Duramaximizer (not recommended!). You would gain no advantage increasing fuel rail pressure, if the problem is with the supply end. It would likely exagerate the problem.

It's my guess your problem is not engine related. Your choice of fuel could have everything to do with it. The fuel system is designed to use industry standard #2 Diesel. If you are using anything else, it's up to you to accommodate it. The current OEM filter is pretty restrictive, even with warm #2. Using a heavier fuel would certainly complicate the issue. A fuel lift pump may negate the issue altogether. What fuel are you referring to? Bio?? Veggie?? Bunker?? Asphault??

[Kennedy]

Thanks for the quick replies guys. JK, by weak pump, I assume you mean a weak injector pump. Can the regulator be reprogrammed to a higher PSI with a typical aftermarket programmer? Would a lift pump help? The reason I ask about viscosity is because the fuel I'm using is a higher viscosity then #2 diesel. Not only am I new to diesels but it looks like I'm using a fuel not many people in the forum have experience with yet.

I think you need to tell us the whole story ie "higher viscosity than #2 diesel"

Rather than wait for the reply, I'll assume it's biodiesel. This is likely loading your filters more quickly. My first suggestion is to use my Fuel Filter Restriction Gauge to verify filter condition and system restriction.



http://www.kennedydiesel.com/images/Dmax-fuel-filter-rest1.gif

[menarda]

I'm using home brewed biodiesel via the dieselsecretenergy method for about $0.40/gal. I filter the fuel down to 2 microns. I've been using this stuff in my home heating system and a hot water heater in another house for 8 months without any issues. Now that gas has gone over $3.00/gal in my area I felt it was time to get a truck to run this in, considering that I drive over 100 miles/day. Being a diehard Chevy person I naturally bought a used Duramax. I put this stuff in my tank and had a 'lean condition' code after 200mi, so I changed the fuel filter. I've put on almost 1,000 miles total without any other problems. The previous owner put about 10,000 on that filter, so I'm walking on egg shells waiting to see how long a filter will last. If I come across any other issues I'll install a lift pump and buy the diagnostic gagues, and see what happens. Otherwise if I get to 10,000mi I'll just change the filter on that schedule and consider myself lucky. Thanks for your help on this guys.
;)

[Prestonia24]

I'm using home brewed biodiesel via the dieselsecretenergy method for about $0.40/gal. I filter the fuel down to 2 microns. I've been using this stuff in my home heating system and a hot water heater in another house for 8 months without any issues. Now that gas has gone over $3.00/gal in my area I felt it was time to get a truck to run this in, considering that I drive over 100 miles/day. Being a diehard Chevy person I naturally bought a used Duramax. I put this stuff in my tank and had a 'lean condition' code after 200mi, so I changed the fuel filter. I've put on almost 1,000 miles total without any other problems. The previous owner put about 10,000 on that filter, so I'm walking on egg shells waiting to see how long a filter will last. If I come across any other issues I'll install a lift pump and buy the diagnostic gagues, and see what happens. Otherwise if I get to 10,000mi I'll just change the filter on that schedule and consider myself lucky. Thanks for your help on this guys.
;)

Just looked up the info on that website (dieselsecretenergy.com) and it seems that their "bio-diesel" product truly isn't what's mainstream bio diesel at all, it seems that they take filtered vegetable oil and add catalysts to make it thinner (give same viscosity of Petro Diesel) so that it can be directly added to the fuel tank...

interesting...

Upon further reading, it seems that the viscosity is higher than B100, but less than VO... and i doubt my new 2006 Duramax LBZ will like the high viscosity of VO....

I'm taking my 3rd Organic Chemistry class, this year, so i'm not worried about handling "potentially" dangerous chemicals such as Sodium/Potassium Hydroxide and Methanol... Just as dangerous storing gasoline in your garage...

All in all, i'd take the dangers of processing my own FAME Biodiesel (Fatty Acid Methyl Esters, aka Transesterified Vegetable Oils) removing the Glycerine, instead of burning all that crap out the rear end, most certainly eventually fouling up the CAT i have on my new truck...

[Kennedy]

I think if I follow Prestonias post he means that it would be better to "brew" it as real B100 which is what I would do and then blend at no more than B50. B20 is where I shoot for.

Be ready for potentially short filter change intervals...

[DmaxMaverick]

Dieselsecretenergy???


I know of several guys in a PS group here that have replaced entire fuel systems due to that stuff. Mothballs. That's the secret. Search this website, and just about any other LT Diesel site, and you'll find much discussion on the subject. I know of several folks that still use it, and will, until their truck gets sick of it.

I agree with the above posts. If you are going to use VO, brew it. Don't use the veggie snake oil stuff. The consequences are just too high.

[Prestonia24]

I think if I follow Prestonias post he means that it would be better to "brew" it as real B100 which is what I would do and then blend at no more than B50. B20 is where I shoot for.

Be ready for potentially short filter change intervals...

Exactly... Brewing it, using Methanol/Ethanol and some sort of Hydroxide..... I don't buy into this thinning of WVO using other chemicals, it still leaves all the glycerine in your system and i don't want syrup flowing through those brand new bosch injectors... I doubt GM will warranty my fuel system if they find glycerine coked up everywhere....

[menarda]

I'm sorry guys, I didn't want to turn this into a Biodiesel post, I just wanted some info into the inner workings of our fuel systems. I've read all the bio posts on most boards like this one a few months ago, so I know what I'm getting into, but I'm not afraid to try something new. The fact is that the price of fuel has trippled over the last 5 years, while my salary has been cut in half. And I have to commute 100 miles/day for the closest low paying job I can find. Now I'm not a biochem student, but I am an engineer, and if our diesels were initially designed to run on peanut oil, than they can run on veggie oil, and #2, and K1, and gas. If they can run on all that, then they can run on a combo of that, what ever mixture creates an acceptable viscosity to the ECM of the vehicle. It cost me $150 to build my processing station to make the DSE bio for $0.40/gal and takes 15min to make and fill my tank. I'm looking to save $$, so I wasn't interested in buying a $3,000 processing station to make true bio for $0.70/gal over a 48 hour period. If the DSE bio doesn't work and destroys my fuel system then I'll replace it and move on to brewing true bio. The truck has 143,000 miles on so the fuel system is no longer under warantee. I bought this truck to experiment with, if something fails, then I will have learned something, made corrections and moved on. So far, I've put over 1,000 miles on it with the DSE bio. Even if I have to change the filter sooner I'm still saving major $$. It costs me $14 for a 34 gal fill up instead of over $100 at the current price of $3.10. Even if I had to change a $30 filter at every fill up I'd still be saving over $50, big deal. (saop box) It's time we Americans stop acting like a bunch of sheep and use our inginuity and think for ourselves to stop being slaves to large corporations who are bending us over for every penny we earn. Exxon/Mobil is making record profits and people are still lining up for $3.00/gal at the pump. I wave at them every time I go by a gas station I used to frequent, but it does feel odd.

[Kennedy]

Simple answer: Do what you want, there's no viscosity sensor, BUT if you are having problems now they will likely get worse.

all sheeps#$t aside, IMHO it just isn't worth the risk to save a few bucks, and it doesn't take a lot of effort to process your fuel into something far more suitable for these EXPENSIVE and sophisticated fuel systems. You even can build your own process station.

I like bio, and burn it when I can get it, BUT I do things a bit more conservatively and on a level that I consider more safe...

[DmaxMaverick]

Your engine warranty has expired, but you still have an extended warranty covering certain injector issues. That warranty is good for 7 years or 200K. If you do have that issue, there's a good chance your dealer won't cover it with goo in the fuel system. Injector replacement on these newer systems isn't trivial. Even if you do it yourself, it'll cost $1K+. The dealer will get anywhere from $2500 to $4500.

Also, your current Diesel engine is much different than Rudolfs original design. It was not designed, at any time, to run on peanut oil. A 50 PSI fuel system is a lot more forgiving than one rated at 23,000.

[ISEEDIT]

Any time you use "BIO" fuels you can expect at least 2 and most likely 3 fuel filter changes as this stuff really cleans your fuel system (including you fuel tank and bulk tanks or fuel cans/bottels). After 3 filters then you can get a good feel as to how long a fuel system can go before fuel filter maintinance is neccessary. I have double filters on my bulk tank - 10 mic and change them monthly. I haven't had any problems with tractor or truck filters but do change them before recommended hours/miles are hit. Mn mandates 2% bio blend - I was already using 10% blend so my storage tank and machines/vehicles were "conditioned" for "bio" fuels. In the weather we have had this summer, moisture (humity) is more of a concern with my machines. Current Bio-bean oil prices as of today 2.70 - 99.9 % pure soyoil - You fill up at Brewster MN www.MnSoy.com Dyed is less money. Some guy with diesel irrigation motors are running it streight as that was about 40 cents gal less the regular farm diesel. Good luck.