Won't start!

[simon_wall69]

Done quite a bit of work on the car recently. Now it won't start.

My fuel lines were getting blocked with crud out of the fuel tank. I completely drained and cleaned out the fuel tank, reconnected the fuel lines and whilst at it I changed the pre-filter and fuel filter filling the latter with diesel before reconnecting.

I then put about 5 litres of diesel in the fuel tank.

There are no fuel leaks and the lines aren't blocked but the car won't start. When cranked or primed with the hand pump, some air and some fuel is pulled into the fuel lines (I can see it in the pre-filter.)

Do I just need more fuel in the tank?

I don't want to put more in just in case I have to sypon it out again.

The car is w123 300 diesel.

Thanks in advance.

 

[David Nock]

I'm no expert on diesel fuel systems but I think 5 litres is way too little. I recently changed the petrol tank on our Mazda and when I refilled I went for about 12 litres.
I would say 10 litres minimum to avoid air entrainment

 

[Blobcat]

The air in the lines is the issue as I see it, you need to get rid of that and make sure that all the O rings are good and not letting any air in.

 

[simon_wall69]

The air in the lines is the issue as I see it, you need to get rid of that and make sure that all the O rings are good and not letting any air in.

The only o rings I have seen are on the filters, the fuel lines just have jubilee clips on, has some previous owner made some dodgy repairs?

 

[roofless]

check all fittings ect & try priming the filter by pre filling with diesel i had to do this in the past due to a faulty primer pump & it alwas worked

 

[simon_wall69]

Seems like fuel lines are blocked again.

Looks like new fuel lines! Another messy job!

 

[robs-mbz]

Try filling the filter with diesel, I had a bitch of a job starting my E300TD after a filter change!

 

[simon_wall69]

It is already full

 

[Aussie Nick]

Ok.Time for the "Start Ya Bastard" a little old Aussie remedy from Down Under.
According to dieselman on a previous post the Mercs are self priming. However you may have crud blocking the injectors,which you probably have missed.
Try loosening each injector one by one. When you loosen one, crank the motor over .You should see the crud/air bubbles and diesel coming out of the threads. I suggest that you loosen a fair way to enable the debris to come past the injector base threads.Once you see the diesel coming through the threads You retighten quickly to disallow any air sinking back in.
Repeat this procedure for every injector.
You maybe able to start it at this point. If not obtain the Start Ya Bastard or equivalent. May be called Aerostart, where you are .You need to spray it directly into the air intake after removing the air filter. Use it sparingly at first . A few good squirts should suffice but do not hesitate to crank quickly after you have sprayed as delay will result in evaporation of the substance.

 

[simon_wall69]

I might just try this. Car doesn't self-prime unfortunately cos it's old.

Unbelievably took the other w124 e300 diesel out for a pootle today and had an identical problem. Fortunately, it was the o-ring on top of the prefilter that had perished, and I had a spare and a wrench in the boot.

It looks like the veg-oil economising is taking its toll on the fleet.

Maybe should just drive around in the 560 from now on.

 

[brandwooddixon]

Veg oil does have a tendency to eat at certain seal compounds. I don't know whether it's possible to buy different ones for MB vehicles though.