W202 C250TD failing to start...

[AlexB]

Hello chaps,

This place has come as a recommendation to me as I need to sort out an issue with a part exchange I took in recently.

The vehilce in question is a 99/T C250TD Auto. I was using this as my daily driver up until I laid it up briefly around the time all the snow came down over Christmas. It has always been a bit of a struggle to start as the glow plugs need replacement with the light staying on for sometime after start up, but now it will not fire at all and just cranks as if it there was no fuel.
Surely this is more than a glow plug issue? My mechanic has suggested it likely to be a faulty injector but can't be certain, I'm hoping this not to be the case as I know that can be costly.

Any suggestions gratefully received.

Regards,
Alex.

 

[Iain]

Almost certainly will be down to the glow plug issue.

 

[142 TPL]

They are also known for fuel draining back to tank after a bit of a layup. Fill the fuel filter with fuel and try starting with a snort of easystart.
Works for me

 

[SilverSaloon]

i had 1 glowplug out for about a month - today i got around to replacing them as the car has been harder to start last few days and flattening the battery trying. turns out, now 3 are dead. replaced them all - starts on the button again.

you can test the glowplugs with a multimeter at the relay plug to see what ones are dead.

 

[91dm]

They are also known for fuel draining back to tank after a bit of a layup. Fill the fuel filter with fuel and try starting with a snort of easystart.
Works for me

This is fairly common, mine would start but took a lot of turning. Will it start if you keep turning?

 

[AlexB]

Cheers gents, very helpful.

Are new glow plugs easy enough to fit?

The car would evenutally start after lots of turning last time this happened before the cold, but now there's not even a glimmer of hope, I'm sick of jumping it and flattening the battery.


Alex.

 

[SilverSaloon]

Get the engine hot before you start the job as the plugs will come out easier with it hot.

its a hassle but you need to remove the manifold to gain access.

other than that its an easy enough job aslong as the old plugs come out ok - beware of them snapping in the head though. 2 of the 3 i did today were stuck in hard. i had to loosen them off and then run the engine with the manifold off, pulling at them with plyers until they shot out like bullets to get them out!! a bit dangerous but was the only way!!!

 

[AlexB]

Cheers,

Might struggle to get the engine hot it's it won't start... but I'll have a butchers tomorrow and see how it pans out. And as far as you know you don't think this is likely to be an injector problem?

Cheers,
Alex.

 

[142 TPL]

Doubt very much it's injectors

 

[91dm]

I had the same problem with fuel draining back to tank. It got worse over time, ended up where the fuel would drain back overnight on a level surface. Turned out to be the fuel pipe on the filter, the end had perished. Sounds the same problem as your having.

The glow plugs are easy enough to do. Manifold has to come off but that’s it really. One or two of them are harder to get at. It does help to get the engine hot and take your time when removing them. I didn’t have any that broke but it’s common. Hope that helps.

 

[SilverSaloon]

use a multimeter and pull the chock block off the glow plug relay. set it to OHMS and test each pin one by one. the pins are marked with a number which corresponds to each glow plug.

if you have 2 or more out i reckon its definatly the GPs.

whatever happens, i'd replace the GP's 1st before anything else as you know from the light not coming on as normal atleast one is dead.

also, if you are taking the manifold off, now would be a good time to replace all the rubber o-rings on the clear pipes.

 

[Smiley]

It is most likely a combo of 1. less than perfect glow plugs 2. fuel draining back and 3. the o rings on the fuel delivery pipes gone brittle and letting air in to the pipes.
Get a set of new pipes from MB (about £20) and then get it fired up - as SS says get it nice and hot to do the glow plugs - and dont force them or they will snap off - and then it will be a p/x you will wish you had never seen

 

[crookedvulture]

Did you ever get this sorted? I have a 1998 C250 TD whcih has recently becom a nightmare. Sounds really similar to your problem.
Car was running fine until a couple of weeks ago when I went to start it and it wouldn't fire. Engine was turning over , but no joy. I took it to my local Indie who found that the fuel filter housing was leaking so changed it, bled the system, and the car started first time. The next morning though, it was back to not starting. Took it back to the indie who checked the pressure in the system and could not find any leaks, what he did say though was that the pipe in the fuel tank that send diesel to the engine seemed to be too high. The car had 1/4 according to the guage but it was just sucking up air. Said that as long as I keep the tank more than 1/4 full it should be fine.
Bit of a pain, but decided I could live with it so went and filled up. Car ran fine for the rest of the day. Sadly, the next morning... It wouldn't start!
Pushed it back round to the indie who had another look and this time changed the fuel filter. He kept it overnight, and when he tried it in the morning it started so we presumed the problem was gone.

That was on Friday. Guess what's happening today? Yup, car wont start.
Any ideas? I am stumped..

 

[Iain]

When the car is in his workshop it is undoubtedly a lot warmer so starting is easy. Back outside for a cold start and it then becomes more difficult. It will primarily be the glowplugs that are a problem.

 

[crookedvulture]

Thanks for the reply. Do glowplugs tend to die overnight? I always thought there would be a more gradual decline in performance and starting ability. I only ask because the car used to start instantly and run perfectly.
Is there an easy method for testing the plugs?

 

[SilverSaloon]

Is there an easy method for testing the plugs?

yes:

Mercedes Diesel Glow Plug Repair

 

[e320cdiowner]

yes you remove the plug from the glow plug relay then measure ohms between each pin on the lead plug and earth . It should give you around 5 to 10 ohms for each plug connection. Normally the heater elements get burnt out and you have a very readings . Anything more than 30 ohms change it .

This is what I did for my w124 300d w210, I have not the need to do on my w210 320cdi .
I am not sure about your car.

 

[crookedvulture]

Thanks guys, will try and check this tomorrow and let you know.

 

[crookedvulture]

Sorry for the delay, just got the car back from my Indie. He tested the plugs and they are all fine. Say it must be the fuel return pump (arrrrrrr... it might of been the high pressure pump.. curse my lack of memory), as when the car is parked facing downhill it starts first time every time, but if it is level or facing uphill it refuses to start.
What do you think? Could it be a pump, or is this more likely just the O-rings? I have been given a number for a Diesel specialist so will call him tomorrow but just thought I'd ask what you guys thought.

Cheers!

 

[toolman1954]

Hi C.V.-- almost 12 months ago my 300TD suffered the same problem of not starting and only by chance did I discover that it was only when I was parked uphill that it would not start. Eventually I had my indie diesel specialist fit a whole new set of plastic fuel pipes and also a non return valve to stop the fuel draining away, and problem solved.