PLEASE HELP my E300d won't start!!

[94.300td]

May I first say that this forum is excellent and it's got me out of trouble before, now I hope someone can help me with this...

Its a 1994 W124 E300d estate.

I serviced it yesterday, fluids and filters, then took it for a quick run, no probs...

This morning it turned over and fired a couple of times but then nothing, just turning and turning, I flattened the (new) battery then tried jumping it from another car, no go.

O.K. I thought, it's been a bit iffy on cold mornings so I thought GLOWPLUGS!

After a 50 mile round trip and MUCH dismanteling later they are fitted, no mean feat in the snow on my drive I can tell you!

The big moment, plenty of heat, fingers crossed I turn the key, nothing...

turning and turning.

Does ANYBODY have any ideas? something I missed on the service or when I changed the diesel filter?

I am at a total loss...

 

[Parrot of Doom]

Well I'm no expert but I had a similar problem when I changed my diesel filter on my W210, which was traced (stupid of me) to the fact that I hadn't correctly installed the new O-rings for the filter.

If I was you I'd remove the filter, fill it to the brim with diesel, and check that its perfectly sealed, as well as any pipes going to the engine from the filter. Air in the pipes is a dead giveaway.

 

[Bolide]

E300 Diesel won't start

It will almost certainly be air in the fuel system. This has been covered in great detail on this forums (and others) so a quick search will find the relevant posts

Basically when you disturb the fuel pipework the O-rings tend to leak and air is drawn in. Reseal the pipework with new O-rings and the problem goes away

Another clue is if the problem happens when the car's parked nose up but not when it's nose down

They are almost impossible to start when this happens but putting your foot all the way to the floor seems to help, even if the effect is purely psychological


Nick Froome
www.w124.co.uk

 

[94.300td]

Cheers guys, you've given me a start point for the morning, the fuel filter...

Is the fuel system self priming, e.g. if you run out of fuel, do you just put more in and crank the engine untill she goes?

I will let you know how I get on... Dylan

 

[Bolide]

Self-cranking

It is self-cranking but when there's air in the injectors lines the injectors don't crack open, no fuel gets to the engine and the thing doesn't run

You need enough pressure to crack open the injectors. Then everything is rosy...


Nick Froome
www.w124.co.uk

 

[94.300td]

Learning all the time

Cheers Nick, excellent website, lets say I cocked up the o rings on the diesel filter and air is getting in, If I fix the leak will the air already in the system work it's way out? Dylan :-?

 

[Parrot of Doom]

Yes, but be prepared to be cranking that engine for a couple of minutes And be prepared to charge the battery up.

 

[pcman_jh]

Non starting - air in pipes

My experience with my C250 Diesel with air ingress is to fill the fuel filter with diesel, position it manually where it's fitted and applying upward pressure to make a seal against the rubber O rinig, then put more diesel thorugh the bolt hole until it's to the rim, then fit the retaining bolt. If you do this you save your starter motor from cranking for several minutes. As soon as you get a splutter from the engine, you're not far from it being purged of all air ingress and tha't it ready for another 5 years worth of effortless starting!

PS - My C250's air ingress was caused by the bleed hoses that run from injector to injector. Although they looked in good shape, they crumbled in my fingers when changing them (after changing every other ) ring on the car).

 

[Dunx]

I have been having similar problems with my W210 E300 TD. The trick for me seems to be parking nose down, as Nick already pointed out. If the car is parked nose high and there is air in the system you can just about forget starting it. If you can move the car so the nose is lower than the back end (difficult, I know on such a heavy car when there is no power steering!) then it will be easier to start. It will need a lot of cranking to get rid of the air (around 45 seconds to a minute for me) but it should go, once you seal the air leak.

Let us know how you get on.

Duncan

 

[Bolide]

Air leaks

You just have to be ruthless in tracking down & sorting air leaks. Once this is done it will be effortless starting for the next 5 years, as pcman_jh said

The pipework itself is OK, but the O-rings tend to flatten with age (so they acquire a D-section shape, not a O-section) and then leak. If you pull off one of the clear hoses and look very carefully at the O-ring you'll see what I mean. It'll look flat. Replace it with a new one and it will look different. I treat the O-rings as a service item and replace them as a matter of course

O-rings from the dealer at about 80p each. Two sizes. Get your hands dirty, swear a lot. Job done!

One last thing - the shutoff valve atop the fuel filter can leak. Replace it if you suspect it. It just bolts into the filter from the top through the casing



Nick Froome
www.w124.co.uk

 

[94.300td]

Running sweetly once more

Thanks for all the advice, I I unscrewed the fuel filter this morning and found it half empty, odd I thought because I filled it before I refitted it...

So I checked the O rings, all good, refilled it and screwed it back on super tight.

I turned the key, gave it some heat, and after several attempts it fired up!

I am so relieved...

It performed faultlessly on the 20 mile commute to work then fired up first thing in the snow after my 10 hour shift.

On a different note, when I changed the glowplugs, I checked the old ones as they came off, all but 1 were o.k. but I thought seeing as I made the effort and got this far I would change them anyway because the way I looked at it they could fail at anytime. And incedentally one wouldn't budge so it's still in there because I need the car for work and can't afford for it to be out of action at the moment.

But with the (5) new ones it starts STRAIGHT away, none of the usual firing on 3 of 4 cylinders for about 20 seconds, wierd I thought, because the old ones were good, or so I thoght... anyone else had this? Dylan.