Hard starting diesel engine, any advice?
October 7, 2004 9:09 AM   Subscribe

Diesel engine cold starting problems... { mi }

I have a 1995 Peugeot 306 1.9 turbo diesel. It is a real ballache to get started in the morning now it's got colder.

It takes about 10 x 10 second turnovers before it finally splutters into life, accompanied by a large cloud of white smoke out the back. Once it's started there's no problems with it whatsoever, it runs smoothly and there's no smoke.

Any ideas what could be wrong with the engine, apart from the 110,000 miles plus it's done? Why does all the smoke come out the exhaust pipe? I'd be grateful for some ideas for cheap parts that I can replace to make it fire up better in the mornings. I'm worried for when it gets really cold in a couple of months!

posted by derbs to Travel & Transportation (8 answers total)
My understanding of diesel engines is a bit limited, having only driven them and not done a lot of work on them.

That said, diesel engines don't use spark plugs, instead they rely on the fact that diesel fuel is denser and will explode when it reaches a high enough pressure. Remember that as pressure increases, heat does as well. If the fuel is colder it will take more pressure to ignite.

Diesel engines thus often have things called glow plugs that will help the fuel get started. Some modern diesel engines don't use glow plugs and instead modify the timing so that the fuel is injected after the air has been pressurized more, increasing the likelihood of combustion.

With those facts in mind, if your car uses glow plugs, you might need a repair or replacement of those. If not, you might have a problem with the injection timing.

The smoke? I have no idea.
posted by RustyBrooks at 9:43 AM on October 7, 2004

It has glowplugs. An orange light goes on in the dashboard for about 5 seconds when i first turn the key.

Do the glowplugs keep on warming the engine after the orange light goes off? Maybe if I waited a bit longer before i turned the engine over i'd have more luck.
posted by derbs at 10:02 AM on October 7, 2004

White smoke (as opposed to black, which is normal for a diesel) suggests that there's water or condensation.

Worst case (and very unlikely) scenario- the engine head is cracked. If the car's never overheated and runs fine when it's warm, don't worry about this.

Most likely-- It's got some miles on it, and the gaskets aren't as tight as they used to be, so moisture is getting in to the ignition chamber and making it tough to reach temperature. It's condensing because the engine cools down after it's been heated way up to run.

Replacing the head gasket might help, but there's bound to be air getting in other places. It's a well-used engine. Best thing to do is make sure the glow plugs are all in working order and have a block heater installed if you can plug the car in at night.

If your glow plugs are fine, these labored starts are not going to entirely go away, so make sure that your oil changes are up to date because starts like that stress the engine.
posted by Mayor Curley at 10:05 AM on October 7, 2004

Replace your fuel filter and go to tdiclub.com. It's a site for VW owners, but has lots of great info for running diesels of any type.
posted by jmgorman at 10:11 AM on October 7, 2004

Thanks for the tips dudes. I'm going to get a oil change and a new fuel filter. Would a new air filter help as well?
posted by derbs at 10:37 AM on October 7, 2004

You slit the radiator hose and insert a 120v heater which you plug in every night. The heater is fairly commonly found.
posted by JohnR at 10:44 AM on October 7, 2004

Wow, this question has been a the back of my mind, too. My 6.5L turbodiesel has been doing the billowing white cloud thing also. But then it runs fine and smoke-free all day. The cloud does smell a bit like diesel but I suppose that would be expected? Past time to have a look at that fuel filter ...
posted by cairnish at 10:56 AM on October 7, 2004

A simple trick is to use the glow plugs a little more. Just wait the 5 seconds, then switch off power and redo a few times and then try starting. An older diesel citroen a friend drove took about 30 seconds of heating this way before it was worth even trying to actually start. That said, having a block heater is always a good idea.
posted by lazy-ville at 5:14 PM on October 7, 2004

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