Rough diesel starts - bad glow plugs?

[dieseljack]

Another question for the diesel experts out there (I've never owned one before).

The car in question is an 83 Rabbit L diesel. Granted, it is winter time here in Oregon, but the cold starts on this vehicle seem unusually labored. I heat the glow plugs 2 or 3 times, pull the cold start knob, then end up pumping the gas for 10 seconds or so before she chokes to life. Is this normal for a diesel? We're talking 40 degree temperatures, here. Nothing too extreme. My first thought was that it's got one or more bad glow plugs or that the straight biodiesel in the fuel tank could have crystalized in the fuel filter. But once it's running and warmed up, it smooths out. Any suggestions would be appreciated. Thanks!

[stevethefolkie]

if you're running pure bio diesel (pure veggie oil - no petro included) then I'd expect problems at 40F - the stuff gets really thick - the guys I know who are running recycle waste cooking oil start 'em on good old diesel - have a warming element in the waste oil tank that heats it up - and switch over after a couple minutes - they also switch BACK to regular diesel a minute or two before shutting off - so the waste oil doesn't gel up in their injectors -
My drill was insert key, turn on glowplugs, pull out starter/enricher knob, when GP light went out - engage starter and start engine. It'd run like absolute crap for the first couple minutes then settle down and do just fine. This was running pure petro-diesel. In the winter having a block heater (anytime it was below, say, 45) was a big help. In fact the heat used to come up through my defroster vents over nigth and keep my windshield clear!
Not sure what, if anything other than running down your battery, the multiple engagements of the glowplugs is doing for you. You can check the resistance of the glowplugs (cannot for the life of me recall what its supposed to be - but I can assure you that neither infiniity nor zero are good). The spec should be in Benteleys OR available elsewhere -

Best of luck

Steve

[dieseljack]

Yeah, I've got a Bentley laying around here. I'll check into that. There's also a block heater installed that I've never hooked up but I'm sure works. The fuel isn't veggie oil, but refined B100, though even this is supposed to become more viscous at lower temps.

Thanks for the suggestions!

[stevethefolkie]

Your block heater is your friend when it's 45F or below - the difference in starting is astounding. I'd hook it up and give it a try -

Having "instant heat" in the car (or close to it) is another advantage -

I'm not sure if the winter fuel conditioner for regular diesel does anything for BD (or if it'd even work with it) - I used to add that to mine when it was cold (below 20F or so overnight) - seemed to help.

Best of luck

Steve

[ProjectPurity]

Fuel conditioners like PS Diesel Kleen don't do much. I guess it might help a little, but for the money, just get some kerosene.

Hard starts in the winter are common... cycle your glow plugs twice or get a battery with greater cold cranking amps. My girlfriend has an Everstart MAXX in her Rabbit. She had to extend the power and ground cables a little, but that's alright since they don't make a battery that size for her car. It has 1000 Cranking amps and 875 Cold Cranking amps.... it helps! If you run a trickle charger overnight it keeps the battery warm so you get the 1000 instead of the 875 which also helps a great deal!

I run biodiesel (methyl ester, not SVO) in a 81 Rabbit and an 82 Audi and kero really helps the starts.

Some tips on recovering from gel

- Get the car to somewhere out of the cold like an unheated garage or something.

- Get a little electric space heater and try to thaw the fuel filter first. If your fuel gelled overnight, chances are the fuel in the tank isn't gelled, but rather just whats in the lines and filter. You can dump out the slop in the filter and replace it with kerosene if you'd like... it will probably help.

- once that's been heated for a while heat the lines by putting the heater under the car blowing heat back towards the tank. You shouldn't need to heat the tank directly.

- Dump some kerosene into the tank, it seems to melt geled biodiesel. If your car is anything like this rabbit you can very easily shake the car from side to side. Do this to get the kero to really mix up with the bio. They won't always mix that well in the cold.

- Make SURE your fuel mix is appropriate next time!


PS: Block heaters do NOTHING for your fuel geling up, they merely make the car start with greater ease and less wear (and you get instant heat!)