Lumpy E300TD, changed glow plugs ... now what?

[EekoGeek]

Having started perfectly through all the sub-zero weather, my '98 w210 E300TD, 112k, started displaying the glow plug warning after starting, running on less than all cyclinders for a minute or so and producing a white cloud of smoke on start up. After a couple of minutes (and before reaching operating temperature) it would be back to running well.

Reading a few helpful posts here (thanks!) it looked like the culprit was the glow plugs. The local merc specialist took a look at it and agreed, so I had all the plugs changed. The light has gone out and starting is better but I still get a few seconds of running lumpy and a (smaller) white cloud.

Obviously, I will get back to the mechanic, but thought I would log in here for some expert opinion.

Three addition bits of info that may be significant:
1. Looking back over the service record (afterwards - doh!) i notice a complaint about rough starting and that the glow plugs have been changed c. 12k miles ago
2. The mechanic noted that the glow plugs that came out had quite a lot of black crud on them
3. I'm running on 100% biodiesel

Thanks for any thoughts!
Simon

 

[turbopete]

Three addition bits of info that may be significant:

3. I'm running on 100% biodiesel

Thanks for any thoughts!
Simon

theres your answer for the initial rough running. i ran my transit and my citroen zx on 100% biodiesel. because its effectively cooking oil with a few additives in it, it thickens when its cold, hence the reluctancy to run smooth for a few seconds until the fuel starts to get moving and warm up. had the same problem with both of mine, although the transit hadnt a fuel heater, so took longer to run smoothly. diluting the bio with ordinary diesel should ease the problem a bit, although my zx took a couple of tanks of pure diesel to run 100% perfect after i lost my bio supply. an injector cleaner may also help a bit as i believe the bio makes the injectors a little sticky when theyve been stood overnight etc.

that probably explains the unusual amount of black crud on the glow plugs, when the car is misfiring the plugs do carbon up a bit, in the same way they do when the plugs fail!

 

[roadhog]

theres your answer for the initial rough running. i ran my transit and my citroen zx on 100% biodiesel. because its effectively cooking oil with a few additives in it, it thickens when its cold, hence the reluctancy to run smooth for a few seconds until the fuel starts to get moving and warm up. had the same problem with both of mine, although the transit hadnt a fuel heater, so took longer to run smoothly. diluting the bio with ordinary diesel should ease the problem a bit, although my zx took a couple of tanks of pure diesel to run 100% perfect after i lost my bio supply. an injector cleaner may also help a bit as i believe the bio makes the injectors a little sticky when theyve been stood overnight etc.

that probably explains the unusual amount of black crud on the glow plugs, when the car is misfiring the plugs do carbon up a bit, in the same way they do when the plugs fail!

I'm tempted to say bollox to that but I'm too polite.

It's certainly the easy answer, let's blame it on the 'comedy fuel' (to quote NC). I run SVO in mine, sometimes 100%. I can (though I don't usually) start mine without waiting for the glow plugs and I do not get any white smoke (or any other colour) at all. Granted, the engine coughs a couple of times (which is why I don't do it) but thereafter it's fine. I do give it a shot of Millers with every tankful of SVO. The one downside with Bio is the varying quality supplies. Where do you get yours from? Homemade? Supplier? Do you titrate?
Does this only happen after the car has stood for a prolonged time? Are you losing coolant at all? Whenever I see white smoke I think water.
What shape are the injectors in? If the glow plugs were coked up, chances are the injector tips are as well. Fully functioning injectors are crucial to running Veg oil or Bio. 100 odd k miles is probably as long as I'd give them, they may well last longer for pump diesel but that's less demanding on them.

If it was my car I'd do a compression test and have a close look at the injectors.

Pete, you forgot to mention 'air in fuel lines' in your post.

 

[turbopete]

I'm tempted to say bollox to that but I'm too polite.

It's certainly the easy answer, let's blame it on the 'comedy fuel' (to quote NC). I run SVO in mine, sometimes 100%. I can (though I don't usually) start mine without waiting for the glow plugs and I do not get any white smoke (or any other colour) at all. Granted, the engine coughs a couple of times (which is why I don't do it) but thereafter it's fine. I do give it a shot of Millers with every tankful of SVO. The one downside with Bio is the varying quality supplies. Where do you get yours from? Homemade? Supplier? Do you titrate?
Does this only happen after the car has stood for a prolonged time? Are you losing coolant at all? Whenever I see white smoke I think water.
What shape are the injectors in? If the glow plugs were coked up, chances are the injector tips are as well. Fully functioning injectors are crucial to running Veg oil or Bio. 100 odd k miles is probably as long as I'd give them, they may well last longer for pump diesel but that's less demanding on them.

If it was my car I'd do a compression test and have a close look at the injectors.

Pete, you forgot to mention 'air in fuel lines' in your post.

im only speaking from personal experience. the zx was fine on normal diesel, both before and after running on bio, as was the transit. fuel filters changed regularly etc, and thats why i never put it in the E when my supplier started up on his own again. apart from the fact it wouldnt start on a good day!

 

[roadhog]

I may be wrong but don't Citroens and Transits have rotary injection pumps? Unlike the inline variety found on the Mercs they don't like it up them. Veg oil that is.

 

[turbopete]

that may be part of it, i cant remember what type of pump they used now.

 

[brianbrian]

I don't like the white smoke bit, check to see if you have alot of back pressure in the header tank. Hope this helps

 

[EekoGeek]

Thanks all!

I agree the biodiesel will always be guilty until proven innocent!
A few things make me wonder if it is the bio at fault, though.

Firstly, the car started perfectly right through the really cold spell on 100%. Even when it was -8 overnight and -3 when I started it .... no problem at all. The biodiesel comes from Rye BioFuels who seem to be a pretty large/serious concern. It's derived from rapeseed oil and I keep a spare container full outside by the back door - even when everything was covered by snow, the biodiesel was still v runny.

Secondly, the fact that there is some evidence in the service record of a similar problem (presumably it wasn't running on anything funny then.)

Thirdly, when the problem started I did run the tank down and then filled up with petrodiesel ... but the problem seemed to get worse .... ceratainly, not any better.

So, I think I might look into cleaning the injectors as a first step, after reading a few more posts here. (I'm guessing this is a low cost option!) Then I might see if the problem disappears as the weather gets warmer ...if not I might try running it through a couple of full tanks of regular diesel and see if that makes a difference. The coolant level hasn't dropped (I'll double check)
.... and I'm not sure what a header tank is ... but if nothing else works, I'll be back to ask!!

 

[roadhog]

.... and I'm not sure what a header tank is ...

It's the coolant reservoir.

 

[sweeper]

Normally this problem results from dirty injectors or faulty glow plugs (on indirect engines) other things would be low compression or leaking head gasket (small amounts of coolant in the cylinder can produce this fault on start up, although saying all that, cold weather can cause a perfectly healthy diesel engine to cough a bit on cold starts (my VW T5 has done it from new, sounds slightly off for a few seconds or so, but not always)
If i were worried about it i would have the injectors serviced and do a compression check and maybe a check of the head gasket ( a kit is available to check if combustion gases are present in the coolant.
One other thing that springs to mind is hydraulic tappets (if your car has them) these can cause rough idle.

 

[turbopete]

dont mention low compression on a 300td when im around! its a sore subject. however, mine used to cough and splutter then misfire for 30 seconds or so when i started it first thing, and was REALLLY difficult to start when the engine was HOT!

 

[EekoGeek]

Getting back to the mechanic yesterday, he is confident that there is no probelem with compression. I've just spent £5 at Halfords on some injector cleaner today as a simple/cheap first step.... I'll see if this works!

 

[EekoGeek]

Update: Money spent .... but still haven't kicked the smoking habit. After trying waiting-it-out (!), switching fuels, tank additives etc etc, I was still getting a several seconds of running rough and a Battle of Trafalgar effect whenever starting from cold.
So I took the car to Alan Robertson in Hove. Nothing on the computer, glow plugs and relays testing fine, no problems with low pressure tubes eg leaks or air. Injectors suspected - taken out and tested - found to be (evenly) worn - and refurbished.
Still have the same problem. Alan observed that cylinders 2 and 5 looked a bit 'damp' when able to peer into them... so now wear and oil in combustion chamber suspected. This now seems to be in the category of too-expensive-to-be-worth-it, so will be resorting to parking round the corner from home/work and getting more exercise! Thanks for all help so far and any other genius (and cheap) further insight gratefully received. Simon

 

[Number_Cruncher]

Check the compressions - it's possible the comedy fuel has gummed the piston rings, and if left, more will wash down and react with the sump oil.

The thing is with comedy fuel, people do tend to have trouble when they run their engines on the stuff, but, they're always in denial, and attribute the engine's faults to other causes.

 

[Juddian]

It's threads like this that remind me why i don't want to buy a used Diesel car again, hadn't heard it referred to as comedy fuel before but that seems apt.

If i had an old Diesel car worth the price of a tank of fuel i might give it a go meself, get 6 months before it goes wrong and your well in pocket, rinse and repeat.

 

[Alex Crow]

could be a case of valve seat regression, what do you think NC?

 

[Number_Cruncher]

The 12k life of the glow plugs is a bit poor. I wonder if they were a decent make like Beru, or, were they of spurious origin?

This page may be helpful for the OP;

http://www.beru.com/english/produkte/gluehkerzen/diagnosehilfe.php

 

[dieselman]

Try pulling the breather pipe off and run the engine to see if it breathes heavily, if so suspect worn or stuck rings.
To check the valves remove the inlet manifold and run the engine again, any firing up the intake will be obvious.

 

[EekoGeek]

Cheers all! Excuse my ignorance .. but if it's piston rings or valve seat regression is that major expense in both cases? I'm at the point where it is feeling like good money after bad!
I agree that the last set of glow plugs didn't appear to last long. They were put in by the previous owner who, looking at the service record, complained of rough starts!! If it's burning oil at each cold start, perhaps this might be coking the glow plugs and reducing their life? This time I specified MB originals.
On the comedy fuel - I HOPE I'm not in denial - I'm expecting issues! I'm proud to say I've never owned a car that ran on 'serious' fuel - a Prius, an LPG Volvo and now this old veggie tub. Just trying to save the planet .... and a bit of dough. So, I'm coming a bit unstuck on objective B. :Oops:

 

[dieselman]

now this old veggie tub.

I'm with NC on this one as far as OM606 TD go.

I suspect you have a coking injector causing the glow plugs to burn out and possible ring gumming.

In neutral run the engine gradually from 1200 rpm to 2000 rpm and see if it feels unbalanced.

For now run the engine from a bottle of injector cleaner connected to both flow and return side. If you're lucky that may remove deposits from the injectors.

A trick to remove gum from rings is to use a fine atomised water spray into the intake when driving.