W210 300TD wont start.

[allias]

I went thru few number of posts about starting problems on W210 and I cant find what could be wrong with my car. I should mentioned as I just bought it. But I got no intension to back to seller I want to solve the problem myself (or with yours help).

Before I parked for last time it was starting without any problems. I only had a chance to do it on warm engine but there was no problem. It drove fine without a miss. Had enough power while driving and problem started after 3 days of parking.

I should mention about my glow light staying on. Even when I turn key it wont go off. I know it should go off after 5-6 sec but it constantly stays on. I checked plugs and 5 of 6 are OK. I had spare relay so I used it and its still the same.

Car turns fast, strong and fine (after swaping battery for stronger one) but wont start. I tried 10-15 times (i cant remeber how many times exact as its been a while) and it wont start at all. It doesnt even feel as it would like to catch and fire.

Whats wrong?

1. Pump?
2. Crankshaft position sensor?
3. Ignition switch?
4. Anything else?

 

[SilverSaloon]

If it starts eventually after lots of cranking then i'd suggest some sort of air leak into the system. Check all the o-rings (commonly leak here) and the main rubber fuel in/out piping in the engine bay.

replace all the filters.

if 1 glowplug is dead then the light will stay on (should go off eventually (1 to 2 mins after driving). they all need to be working for it to come on as intended.

my money is on an air leak

 

[allias]

Problem is as it does not start at all at the moment but I affraid of burning starter motor if I will be trying to long.

Air leak - you mean air intake leak or air into fuel system leak??

As far my glow plugs... I know its fifth that is dead. (if 65 on plug stand for 5th plug) Because that one got open circut.

 

[allias]

One more thing... what is OVP relay? Are there any special relays for fuel system?

 

[iscaboy]

Problem is as it does not start at all at the moment but I affraid of burning starter motor if I will be trying to long.

Do not crank for more than 15 seconds.

Rest for 45 seconds.

Repeat up to 5 times then rest for 5 minutes.

Saves the starter, saves the battery.

If it doesn't start in 15 seconds it has "issues".

If it has "issues" simply cranking the starter hopefully / in desperation will not cure them.

Fuel and compression are the only two things you need, if it isn't starting you are missing at least one of them, or enough of each to cross the threshold.

Loosen the injector lines and you'll see if you are getting fuel. Loosen, do not undo or open, half a turn will do.

If not, work your way back through the fuel system until you get fuel.

 

[allias]

I disconnected retuned line (because it was the easiest) and it was pumping fuel while cranking but I just realized it wont be enough because it wasnt behind mechanical pump. I will try that today and see then. I really hope its not a compression problem.

How about crankshaft position sensor? Can that be a reason for non-start like mine? If so where is it located?

Still dont get the reason why glow plug light stays on ALL THE TIME. Whould that be indications for searious problems? I heard it might stay on because air intake leak - is that true?

 

[SilverSaloon]

The glow plug light should go out within the 1st couple of mins if one or more is dead, from previous experience anyway.

I still think there is air getting into your fuel lines and therefore all the fuel is travelling back to the tank, so you need to crank it a lot to pump all the fuel back from the rear of the car to the front.

Just keep cranking, waiting between times as advised above and see if it starts to fire. if it does, continue on. it shouldnt take longer than 5 mins if you have an airleak. i had serious airleaks and it took a couple of mins sometimes.

if you do get it going, try and park with the car facing downhill too as if it is an airleak, this will help starting next time.

personally, for the cost, i'd replace all the seals in the clear pipes, and take it from there.

MERCEDES C & E VITON FUEL O-RING KIT SVO WVO BIO-DIESEL on eBay (end time 19-Aug-10 12:58:57 BST)

get some orings, either from the dealer or from the ebay link above and replace them.

fit a new screw on fuel filter

clean the pre-filter

and try to start it again.

is the area around the delivery valves dry or is it wet?

any wetness around any of the fuel pipes?

 

[DrNick]

If there is an air leak, you will likely see air bubbles in the clear plastic pipes near the fuel filter at the front.

How much fuel is in the fuel filter at the front? If this is empty or low this gives a clue that it is fuel related. You might try filling this up before putting it back together - it may run for a few seconds on this fuel, giving more fuel a chance to get from the tank.

Glow plug lights should go off after a minute or so, once the engine is running, if its as straightforward as one or two broken plugs.

This engine is sensitive to broken plugs - mine was very rough when one went down. If all 6 are down that could well give starting issues (all 6 pointing to an issue upstream of the plugs themselves) and on a cold day - no chance!

 

[allias]

First of all... my car it park upwords . So here it comes

As far glow plugs - 5 of 6 are OK but I got plans to change them all because I want to remove manifold to change pipes (already decide to do it dispite was done or not). I got access for some of those parts so I figure for total of £100 I can get all sorted so why not. It will pay off quick with saying on fuel and starter motor (if I will be trying even longer )

As far as wet spots...there are a lot because my last test then I took line of fuel filter and fuel went all over place (not a lot but some - my mistake ) so I will be cleaning all at the same time.

I really have to look closer on my "white" lines and look for bubbles. I couldnt see anything so far...

Silver Sallon... which delivery valve you mean? Injectors?

 

[SilverSaloon]

it will be hard to see bubbles when the engine isnt running. all those clear pipes should be full of fuel though, with the one going into the pre-filter having a small bubble at the filter end (which is normal). if that one has no fuel in it, then it is draining back to tank..

See my old thread here for all the problems i had, and eventually, at the end, the solution.

http://www.mbclub.co.uk/forums/engine/49844-w124-e300d-fuel-lines.html

Delivery valve seal howto is here....

http://www.mbclub.co.uk/forums/howto/46736-howto-diesel-delivery-valve-leaks.html

hope it helps. Good tip about filling the new fuel filter up with diesel to start with. the car should atleast splutter and die very quickly if you do that. but proove it is fuel starvation.

when cranking, make sure you have a good spare battery, jumpleads, charger etc to hand.

 

[Number_Cruncher]

Leave the delivery valve seals well alone - there's no way they'll cause such a serious no start condition.

 

[Ian B Walker]

First of all... my car it park upwords

Aha a clue. This happened to a 24 valve diesel I had here a while ago. Would not start when pointing uphill. I changed the fuel pre filter (the one by the side of the main fuel filter, about £2) Lo and behold, starts every-time. Worth a try on your car?

 

[BlackC55]

Leave the delivery valve seals well alone - there's no way they'll cause such a serious no start condition.

Oh yes they will.

I had a leaky one a week ago causing this exact fault

 

[allias]

I will get mani gasket and glow plugs tommorow so I will wait till wednesday when I will get all white lines to do complete job.

I should get fuel and pre- filter tommorow and I will change them first anyway. I had no chance to check anything today. I will crack on when I finish work tommorow.

Thanks for all the info.

 

[toolman1954]

Hi, Earlier on in the year I had exactly the same symptoms with my 300TD. I had the Diesel specialists change all the fuel seals which did not cure it, and only by chance did I park the car the other way around and next day it fired up first turn of the key like it always had for the past 7 years. I too live on a hill and the fuel was draining back, and needing a lot of cranking to start it. I went down my local Merc dealers and he suggested a non return valve in the return fuel supply. Evidently it is a common problem with the older 300TD.s --although the valve is not listed as a 300TD part. In the end I bit the bullet and replaced every clear fuel pipe and got the Diesel place to fit this non return valve, and as if by magic , not another problem. The valve you want is MA 000 476 37 32 --- BAD NEWS £26-30 ,, but I assure you it is worth every penny.

 

[iscaboy]

any non-return valve will do, most motor factors should do in-line ones, just cut the pipe and fit.

be *very* surprised if there wasn't one in the system somewhere as standard, eg IP body.

 

[SilverSaloon]

if the system is sealed correctly then an additional Non return valve shouldnt be needed. i considered one when i had all the problems but replacing the seals sorted it out for me. Try that 1st and then fit a NRV if you really need it.

Once you get it running, check for bubbles showing in the clear fuel pipes once its had a chance to purge through. if there are bubbles and you've replaced all the seals and clear pipes then dont discount the main rubber pipes. i bought some 10mm rubber pipe from a motor factor for £6 and now i get no bubbles at all (until next time something goes wrong!)

Also, when you're doing all the filters, dont forget to replace all the little o-rings that go on it, ensure the shut off valve isnt leaking and replace the fuel filter o-ring (not included with the pre-filter itself, need to get seperately or part of the viton kit i linked to above).

Do the fuel tank strainer in the fuel tank at the same time if i were you. This can also cause fuel to pull back to the tank if its blocked and also cause fuel starvation at 1/4 tank.

How much fuel does the car say you have in the tank at present? if its near 1/4 tank or below then dont discount the tank strainer as the culpret.

cheers

Derek

 

[allias]

toolman: Where do I fit this non-return valve? Feed pipe? Return pipe? What is it doing? It completly blocking system to go back to tank??? I know it sound dump but I have problem to understand the concept.

SilverSaloon: it is about >1/4 tank but I think I first need to move it as I got no room to get on a back to change this filter.

--------

One more stupid question... how do you bleed system when I change all the lines? Im sure it will be full of air then

 

[SilverSaloon]

it will self bleed - just run the car for a while (go for a 5 min drive) and it should be fine then. Probably run a bit rought for a bit.

Try and put about 10 litres in the fuel tank. you may find it will start.... (eventually as it still needs to be pumped from the back again due to the vaccum caused by the strainer).

 

[Number_Cruncher]

Depending upon exactly when the engine was made, it's possible that the only non-return valves in the fuel system are in the lift pump - this caught me out too, as I expected a sprung ball non-return valve on the outlet of the pump too, but, there can be just a restrictor fitted on later cars.

There was also a modification made available by MB where a non return valve was fitted into one of the lines near to the secondary filter - I imagine a forum search will find the details of this.

My view of these systems is that the first step is to renew all the plastic low pressure fuel lines, the tank strainer, the primary and secondary fuel filters, and the O ring behind the shut off valve. Nothing in that list is expensive, and doing all of it in one go will cure the by far the vast majority of fuelling problems on these cars.

These fuel systems self bleed, and cranking on the starter motor will pull fuel through - however, it's best to fill the secondary filter with clean fuel through the bolt hole when fitting.

I don't suggest that DIYers rush into doing delivery valve seals, as the level of care, skill, and cleanliness that is required is so rarely understood or available. I'm sure Olly at PCS understands the precautions necessary and the potential for problems. The clearances in an injector pump and the downstream injector are tiny, and the injectors and pump can easily be ruined by dirt. The dirt seen in the pictures of the oft posted howto really make me cringe. Yes, Silver Saloon "got away with it", but, many don't, and stories of injector pumps being completely ruined are not unheard of - serious ££££ !!