Cold starting a diesel

[comptiger5000]

Make sure your fuel isn't gelling up, you have the largest, strongest battery that will fit in there with nice, big, not corroded battery cables (fast cranking is key), as well as working glow plugs. It may take a couple of glow plug cycles and a bit of cranking to get it going, but it should fire.

FYI, if you get white smoke while cranking or right after start with a very cold diesel, that's unburned fuel blowing out the exhaust, and normal until it's hitting on all cylinders. Black smoke is partially burned fuel, and can happen too.

[robchalmers]

Battery, was replaced a couple of months back, so pretty sure thats OK. I just hooked it up to the scenic as I don't want to goose it by continuely crank the Hi-comp diesel.

I'll check the leads and Glow plugs tonight

going to look into a block/tank heater too.

[euromodder]

Originally Posted by robchalmers

turns but doesn't fire

I was going to suggest to check the diesel filter, but if it starts right away with jump cables then it's not likely to be a fuel feed issue.

[ConnClark]

My block heater decided to go belly up right after my glow plugs died. I resorted to buying a cheap hair dryer to throw under the hood and a blanket over the radiator and hood. Hair dryers usually draw about 1500 Watts or more. It works but takes longer than using a block heater because it heats everything under the hood.

[JasonG]

If the glow plugs check out fine, get a block heater, they are a wonder!

I also thik youre getting some fuel gelling if it wont go above idle for a while. VW sends fuel back to the filter to try and heat it up some. That can help but takes a few min.
To check, pull your fuel filter when its cold. If it looks like it has Vaseline on it, your diesel is gelling.
I am a fan of "Pri-D" but "seafoam" works well too.

WD-40 is safe to run a diesel on. Unlike ether it will not harm the engine. Mechanics on the big diesels use it to keep the engine running while a new injector pump primes itself. I keep a can in the truck for the just in cases, Haven't needed it yet though.

[comptiger5000]

Clark - The hair dryer should be used to pump hot air into the intake, as close to the manifold as possible. That will make it much easier to start the engine, even without waiting for it to all warm up first. It is similar to the intake heaters found on some diesels instead of, or in addition to, glow plugs.

[ConnClark]

Originally Posted by comptiger5000

Clark - The hair dryer should be used to pump hot air into the intake, as close to the manifold as possible. That will make it much easier to start the engine, even without waiting for it to all warm up first. It is similar to the intake heaters found on some diesels instead of, or in addition to, glow plugs.

Actually I did try that unsuccessfully.

Air temp isn't the problem. Its mainly fuel temp. Below a certain temp the fuel doesn't atomize or have the vapor pressure to emit vapors to ignite. Glow plugs add heat to the combustion chamber right next to the injectors. This heats the fuel some and adds heat to the combustion chamber walls so it doesn't sap heat away from the compressed air.

[comptiger5000]

True. In extreme cold, fuel atomization is a problem. In that case, hit the injector pump and lines with the hair dryer for a couple minutes before you stuff it down the intake and crank. That should get it going, after which it should run ok on its own.

[robchalmers]

Think I might have found the issue, the primary low plug connection was slightly corroded and a little loose, so I emery'd it, gt80'd it and nipped it up.

Catches quicker now - tomorrow morning will be the big check!

[Varn]

My jetta lights up quick so far. I have had to replace the glow plugs. The two under the fuel pump were bad.

The start lever needs to be pulled and sometimes a bit of throttle helps. If It doesn't light right up I go through another glow plug cycle