Curious:
I was reading the owners manual about cold weather starting, and it states sometihing to the effect that: below 0 degrees, pump accelerator three times before starting. My question is what does this do?

Jason

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46 WDX Power Wagon

84 300TDT daily driver

don't know. all i know is that if i do that the engine is harder to start.
if anything i crank with the pedal about 1/2 way to full power until it starts.
otherwise no pressure on the pedal at all.
block heater on for 3 hours prior startup in that kind of weather for sure

gee i'm soo looking forward to it..

any snow up your way yet?

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1984 300D Turbo - 231k....totalled 11/30/07 RIP

I agree, today I tried starting mine without ever touching the pedal when it was about 27 degrees out, I let it glow for....maybe 20 seconds (I installed the extended glow relay last year...so it glows a couple minutes when cold) and then I cranked it, after 3 rotations or so it was running no problem. When I have pumped the pedal or held it down a ways, it takes longer to start and the engine coughs for a few cranks....so I will not be using the pedal anymore....now that I know it starts much better without it.

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Hmmmm.... I going to stop pressing the pedal from now on.

Anybody have any scientific data as to why the car might start easier ?

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Audi TT

I was at Lake Tahoe a few years ago, high altitude and about 30*F, '80 300SD which usually started easily. It wouldn't start with my foot on acelerator about 1/2 way which is what I usually do.

For some unknown reason, I left my foot off accelerator and it started. From then on I didn't step on accelerator and it started easily.

I have no explanation why it wouldn't start with accelerator depressed in the cold high altitude.

P E H

Too much diesel per little bits of air getting in the engine?
I could forsee this being a problem when starting...getting your mixture right to allow for the best burn when super cold is important.
Any other ideas?

I dont think it is a case of too much fuel.. as I understand it, diesels Always run lean (unless injection pump adjustments have been made)
that brings up the question of :has any one ever heard of flooding a diesel?

Jason

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46 WDX Power Wagon

84 300TDT daily driver

good thread. here at 5500' if i touch the pedal before cranking, it's like a gas engine flooding. i have to let it glow maybe 20 seconds after the glow light goes out, then start cranking and slowly give it some pedal. too much too soon and it will "flood". as the temp gets colder, the process is slower. strangest starting diesel i've ever had.
robert

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Current money-pits:
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78 300D 100k miles(60miles/day)FOR SALE
91 Jetta Diesel 250k miles (80miles/day)
82 Toyota Diesel pickup 150k miles; out of service for a little while with a valve problem.
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57 180D lots of miles(gone but not forgotten)

Everyone should use the method which works best for them...
Keep in mind yall are talking about 20 year old cars.... and when new may have been a little different.

I do not think, since our fuel injection is a mechanical system tied by the chain to the injection pump , one can flood a diesel.

I think that the barometric stuff tied to the governer and amount of fuel per stroke may have needed that pedal movement... Or might have needed it depending on weather changes since the engine shut down....

Much like on gas cars where one would put the pedal all the way down to make sure and release the choke cam.... which was held in place by a hot engine at the point the engine was shut down... but which needed to be in the fully closed position when trying to now start a cold engine....

Believe it or not, Greg, you can do this and it can occur quite easily. I've done it several times, especially when the vehicle has one, or more than one, bad glow plug.

I've tried to start the 617, in the old 123, at 25 degees with the typical 1/2 pedal and it would try to fire on one or more than one cylinder but would never climb that curve up to finally running on its own. I already knew that I had a glow problem with it.

So, I let it sit a minute or two and tried to start it with no pedal at all. It cranked for a bit and then began to start on one and then more than one cylinder. It took at least 30 seconds, maybe more, before I felt that I was positive that it would run on its own. Only then did I release the key. And, surprised as all hell, there it was at a perfect idle.

When the glow system is not running perfectly, it appears that too much fuel will serve to reduce the cylinder temperature and it will not start.

I had a similar experience with the 617 in the SD. I had a weak battery, a bad glow plug and 15 degrees ambient. No start. Not enough crank time. I took the unsafe method of a touch of ether. No start. Why? Cylinders too rich to fire, even on ether. Too much fuel saturating cylinder.

Remember, all the time that the engine is cranking, it is stuffing fuel into the cylinder that the cylinder does not need. If you crank it for 30 seconds at 1/2 pedal, it becomes less likely that you are going to ever get it to start that morning because of all the fuel in there.

My general feeling is that if it won't start with 1/4 pedal, adding more fuel will will probably be counter-productive.

i have to agree with brian. in the very cold i find leaving the starter cranking for say upto max 30 seconds with no pedal is preferred. once the engine gets fully warmed after initial morning startup, usually you will have no problems starting during the day if the engine is not turned off for a long period .. say more than 4 hours. at work we used to go out at lunch just to run the car for 15/20 minutes due to no available electric outlet for the block heater.

naturally the ideal is using the block heater. mine will start on the first couple revolutions in below zero F with the block heater on for just 3 hours prior.

no need to stress that you need a really good battery in this kind of weather.

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1984 300D Turbo - 231k....totalled 11/30/07 RIP

I take both vehicles on multiple day business trips in the winter. In the hotel room I contemplate whether it is going to be 0 degrees or 15 degrees the next morning. Every degree above zero matters, as you all know.

Once, in Pittsburgh, it was going down to near zero and I strung a 100 foot extension cord out the second floor window and down to the vehicle. Naturally, the vehicle was quite pleased with this. And, apparently, it was so cold that the management did not even go behind the building that night.

Gosh, Thanksgiving morning and yall ganging up on me already.... LOL

I think yall changed the parameters of the question to ' cold engine starts' from the flooding question...

I do not agree with the cooling effect of the fuel because if the cylinder bore is warm enough in combination with the air temp and the speed of compression ( assuming good compression ).... then the air should be hot enough to fire the fuel spray.

Brian, if you know you have one or more bad glowplugs ... PUT GOOD ONES IN ! LOLOL

But lets say one has one or two bad glowplugs causing the situation Brian describes.... if the bore/air/speed of compression are good for the other cylinders then the speed of compression should be good on the next revolution of the engine.... due to ignition in those... still a cold engine situation...

So I really think you can get too much fuel into a cylinder... but not by pedal position... and that the original instructions listed have something to do with barometric pressure compensation by something in the load sensing part of the injection pump...

And the other question is whether, in those cold situations you describe, yall are using the 45 second glowplug warmup before trying to start... (?)

Brian,

I've used the extension cord at motels already. Look for a soda machine (they have to be plugged into something) if you can't get close enough to your room. You can even pull out the soda machine plug if you have to because unplugging it in the cold won't hurt anything but taking along a triple grounded tap may help.

The things we Diesel owners have to go thru. But its worth every bit of trouble to hear the engine roar, or should I say rattle, on a cold morning.

P E H

I have noticed a difference in the way my 603 starts in relation to the position of the pedal. It has consistantly started better w/o touching the pedal as opposed to following what the manual states. Not having started it yet in the extreme cold, I may find this winter that I am wrong.

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Steve
'87 300TD - 132K - Soon 4-Sale
'84 300D Turbo - 122K - Driving
'77 VW Type II - 77K - Restored
'08 250EX Ninja
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