[Vwdiesel] cutting diesel, cold starts. was bad fuel.

[Sandy Cameron]

You wrote:
>I have noticed that my mileage can vary widely depending on where I get my 
>fuel, the Shell station near my home that has been 4 or 5 cents cheaper a 
>gallon than any other station in the area, usually sells diesel that cuts my 
>mileage by 20% after a couple of tanks.

As most are aware, you can mix a large number of petroleum (and vegetable)
products with diesel, and the engine will still run. Even things that it
would not run on fed straight.

The diesel will help light off low cetane oils, and some times give good
mileage if it burns well when lighted. I'm no expert on flash points, speed
of burn, etc. but all these factors enter in.

My canola 50/50 experiment worked very well last summer, and the car realy
liked it and ran better than on straight diesel . I have all the stuff for
the dual fuel system now, and hope to get it in soon. Winter here is tough
on diesel starts, and I have a need for a wilderness start reliability
(generator in the trunk) at my camp, so I apply all the below.

The engine needs a fuel that will flash at the temperature of max
compression in the cylinder, or it will not start. Hence the need,
especially in winter, for a low flash point , high cetane fuel.
Adding external heat, block heater, glow plugs,  etc will add to the basic
heat of compression,  and raise the flash temperature in the cylinder,
Then you can use lower flash fuels.
Also. the fluidity of the fuel is important for good atomization, allowing
the fine droplets to reach the flash point quicker.
Alll this action is happening in the last 2 or 3 degrees at the top of the
compression stroke.
If it lights, serendipity.
 If it doesn't, you walk.  (-20C here this morning)

OH, and yes, cranking speed. Light synthetic oil, healthy battery, good
condition starter, big fat cables, all contribute.

And PLEASE, don't boost it with a big truck with the engine at high idle.
The over voltage will blow your glow plugs and might harm your starter.
Much better to attach it to the back of the truck and pull it at 25-30mph in
4th gear until it runs on its own....it will eventually.

Again, 4th gear only, if you dont want to replace your tranny.

Cold start lessons for today.

Sandy