2/3 diesel, 1/3 89 octane

[rapidoxidationman]

I finally did it. After a decade of diesel ownership, I got fooled by the green handled fuel dispenser at an out of state gas station. I was only about 11 gallons down, but didn't realize it was gasoline I was dumping into my 35 gallon tank until the handle clicked off.

Argh.

Sooo I put an extra pint or so of Power Service Grey bottle (sorry, JK, but it hasn't failed me yet...) to add a bunch of extra lubricity to the mismixed fuel and drove the less-than-5 miles to my destination - 2500 miles from home.

The truck started and ran fine for the 5 miles I drove it, but that could be thanks to the pure diesel that was still in the injector lines and fuel filter.

What sayeth the collective? Should I pay the money get a dealer to dump/fill the fuel tank or will the truck swallow a 66% diesel mix?

I'm in Raleigh, NC doing some work for friends and clients while my daughter attends an Outward Bound program so cold weather shouldn't be a problem but I need this truck to work...

[DmaxMaverick]

Don't sweat it. At all. Go to Walmart and get a gallon of 2 cycle outboard oil, dump it in the tank, and don't look back. The extra lubricity in the additive will offset the gas (which really isn't much worse than modern ULSD), and the 2 cycle oil will restore the viscosity (as well as add more lubrication). Run it down to 1/2 tank and fill it up with #2 (no, really this time). The residual in the tank will be nothing to worry about (no more additives needed).

Actually, after all this mess, you might notice that it runs better for a while. They always do.

[rapidoxidationman]

Yup, it looks like a couple of gallons of good 2 stroke oil is in my future. I did some googling and it sounds like combustion temperature is kind of an issue though - higher temps leading to coking on the injector tips leading to bad spray patterns and eroding injectors... any thoughts on this?

As far as your "you may notice it runs better for a while - they always do", what's the logic behind that? Higher temps burning out carbon deposits?

I'm trying to convince myself that I don't need to go buy (6) 5 gallon diesel buckets and siphon out what's in there, fill the tank with diesel, and slowly feed the 66/33 mix back into it on my way back to Idaho in a couple weeks...

[DmaxMaverick]

No combustion temp issue. I don't know where they get that. The mixture will actually burn cooler. The problem with heat happens when you get past 60% (double what you have), and NOT because "gas burns hotter). It's because the entire chemistry of the fuel system is operating outside its design. At higher concentrations, there isn't enough Diesel to ignite all the gas quickly enough, and the result is more heat leaving the cylinder (NOT staying in there). Too much O2 at first, then it burns off as it is exiting, after the #2 consumes enough oxygen. Exhaust temps may increase, marginally, but cylinder temps don't. The other side effect is power loss. The loss is significantly more than the actual BTU value comparisons. This is because the gas is burning well outside the optimum range in the power stroke. It's easy to add some gas, watch your pyrometer, and make assumptions according to the gage. It's misleading.

BTW....2 gallons of 2 cycle is 1 gallon too much. Probably 1.5 gallons too much, but more of it won't hurt anything. I wouldn't worry about it. I've been through this many times since 1980, on every Diesel technology imaginable. Once you prevent the pump lubricity starvation, the rest is trivial. Most engines don't even notice gas until you approach/pass 50%. Even the early owner's manuals (including GM's) recommended a 10-25% mix of gas for extreme cold conditions.

[rapidoxidationman]

Thanks for the lesson :)
I'll put a gallon of oil in to insure lubricity (and expect the 2smoke exhaust for a while) and keep it full of DIESEL as the fuel guage moves to the left.

[DmaxMaverick]

You'll get no "additional" smoke. Injected oil is fuel. Same as #2. The engine (and exhaust) won't know the difference. Very different than pouring it into the intake (which would be smoky). The reason for using 2 cycle oil is because it is formulated to burn. The stuff actually does very well in the system. I poor it in with every fill (albeit, not that much).

[rapidoxidationman]

When the truck is running it digests the mixture just fine. When the truck is cold (first start of the day) it starts just fine. Starting the truck hot yesterday it needed 3-4 seconds of cranking which was unusual. Today it won't start hot... Possible vaporlock caused by the gasoline?
I haven't driven but maybe 20 miles since the incident and have added 3/4 gallon of synthetic 2 stroke oil and a bit less than a half gallon of Power Service grey bottle...

Suggestions? I do have a new fuel filter but can't see that as being an issue.

[DmaxMaverick]

It could be a viscosity issue, creating more difficulty getting it up to first ignition fuel pressure when hot. Gasoline is more prone to outgassing (vaporizing at lower pressures, such as a suction-type fuel supply system). This could allow an air bubble in the system causing the pump to lose prime (vapor lock, for lack of a better term). Try priming it before a hot start. I don't recommend synthetic oil, necessarily. It only needs to go through and burn. Traditional (inexpensive) oil is more than sufficient. The 2 cycle oil you use should be rated "TC-W3". This oil is formulated for water cooled engines, and is formulated to burn more efficiently at lower, more stable temps.

[Mark Rinker]

http://www.thedieselpageforums.com/tdpforum/showthread.php?t=37866&highlight=green


I applaud the level headed advice you have been given. My proportions were much worse, and I recovered using two cycle oil as well. I have put on almost 50K miles since then, and the truck shows no signs of any damage or ill effects from burning up the unleaded, rather than pumping out the tank.

Also - any fuel filters changed are a waste as well. I retrospect, I pitched a perfect good filter on the advice of the DIC. DMaxMaverick pointed this out in my thread. Any messages to the contrary sent by the DIC are viscosity related, not restriction related, and will correct themselves in time.

My daughter's 2003 Jetta TDI was recently given a dose of 3 gallons (by my teenage son this time - thank goodness he didn't have much money!!!) of unleaded on top of 2 gallons of diesel remaining in a 16 gallon tank. It went only a few miles down the road, and died. Five gallons of #2 carried back to the car in a jerry can brought the mix back to a proportion that it would run on, after some extended cranking to clear the filter and injector lines of the bad mix.

6 more gallons of #2 at the next service station was purchased down the road to top off the tank - and it was again running normally.


WATCH OUT FOR THOSE GREEN BP HANDLES!!! ;)

[rapidoxidationman]

Just read the link you gave to your problem Mark, thanks for that.

2500 miles after the brain fart finds me back in Idaho with all the power I left with 6100 miles ago but a couple of questions:

1) seems like the cooling fan engages more now - I hear it start spinning every 15 minutes or so. Might be the weather; it is hotter now than it was a month ago, but anybody got any thoughts on this?

2) I noticed there's a soot pattern on my back bumper rear of the exhaust now and I put on a pretty good smoke show when I put my foot in it to accelerate from low speeds. I'm pretty sure this was not the case a month ago... Any thoughts on trashing the DPF with my fuel cocktail?

Could this topic be made into a sticky? It'd be pretty handy to have the two or three threads on this in one place...

[DmaxMaverick]

It's significantly warmer now than it was a month ago. Unless you have another reason for suspecting something, attribute the fan activity to the heat. It's just that some incidents make us more aware of some things.

You don't have a DPF (2007.5+). Try peeing in the tank. The EPA seems to think it does some good.