Won't start parked uphill, and now fuel injectors leaking?

[mymymy]

Hi,

I'm not really a very 'car' person, but after being fed up with expensive garage bills I'm trying to learn and save myself a bit of cash.

I have a C250D estate (1996 or 1998 can't remember which), and about 18 months ago I had a problem where if I parked it facing uphill and then left it for a while (usually overnight) then it would not start. Parked downhill, ti would start first time. I investigated and was told that this was common for my model at it's age as the fuels lines had started to corrode and air was getting in somewhere. The Fuel lines were replaced, problem solved. About 2 months ago I got the same problem. As a temporary measure I only parked downhill until I had time to look at it. However on Friday night I had to park it on the flat, which is usually ok, but on saturday morning it would not start. It almost started a couple of times but eventually the battery was too weak. Getting a friend to help me jump it I was able to get it going, but it didn't sound great whilst it was spluttering into life. I decided that I had to sort the issue out.

Working on the previous diagnosis that air was getting in somewhere I decided to check all the jubilee clips on the fuel lines. Not knowing where the fuels lines are I looked in my Haines manual and followed the line back from the fuel filter. Whilst doing this I noticed some liquid on a componant. I think this componant is the fuel injector (see picture below). I dried off the liquid and then let the engine run for a while. It got wet again. When it is not running it doesn't seem to get wet.

i248.photobucket.com/albums/gg182/_mymymy_/feulinjectorleak.jpg <-- picture of the area affected.

What I want advice on is:

1/ Is it dangerous to drive the car at the moment. I have read this thread (on a different forum) http://www.mercedesforum.com/m_51621/tm.htm and so presumably it is?
2/ Are the two issues related? Or is it possible that the leaking fuel injector was caused by the rough start on staurday morning?
3/ Could the leaking fuel injector be the cause of the non starting when facing uphill? If not then where should I start to investigate to fix that problem? (any diagrams of where the fuel lines run would be a great help)
4/ Is the leaking fuel injector something that I could try and fix? ie could it just be a screw that needs tightening? Or should I take it into the garage? How much might I be expecting to pay for this sort of repair?

Sorry if this is a long post with a lot of questions, but any help would be much appreciated.

If I can provide any more information, just ask.

Many thanks

Sam

 

[Bolide]

That's the output of the Injection Pump (IP) and they would only leak when the engine is turning over as the IP is driven by the engine. AFAIK there are seals on the outputs and they may need replacing. You need a special tool to remove the splined doodads shown

Any diesel specialist can do this if they have the correct tool. The Inlet manifold will need to come off and it'd be worth having it cleaned out at the same time

If new seals here don't cure the starting problem I'd look again at the fuel lines, particularly the transparent plastic ones shown in your photo. They're the normal source of air leaks. They just need the O-rings replacing. Doing the whole lot shouldn't take more than an hour

Nick Froome
www.w124.co.uk

 

[mymymy]

Thanks for the quick reply Nick. The infomation given is really helpful, I'll take the car to a garage tomorrow.

If the clear pipes are not leaking (I checked for leaks in all the pipes in that area whilst looking for the source of the liquid on the fuel injector) then how far back down the fuel line should I go looking for the leak. Will I have to check all the way back to the fuel tank?

 

[Parrot of Doom]

They are pressure valves but I can't see them affecting the car's ability to start up. I have leaks there (on the to-be-done list) but they've never stopped the car from starting. The tool is available from Mercedes, some will sell it, some won't. Try http://www.mercedes-benz-parts.co.uk/ if the dealer won't sell you one. The part number for mine was 617 589 01 09 00 but check to see if its compatible with yours as I have a different engine. You also need 5 copper seals (yours is a 5-cylinder right? - if its 6 cylinder, get 6), and 5 o-rings (one for each valve). Take care not to disturb the pump when you remove each valve.

IMO you have another leak on the intake side of the pump.

The most obvious to change is the o-ring on the pre-filter, the line on the bottom left of your image is going to the prefilter. One bolt is all that secures it, you can see it in the pic. Remove that bolt and carefully lever the line and filter out, you'll see the o-ring at the top of the filter. You have to order that o-ring as a separate item it doesn't come with a new filter.

Also check the o-rings on the main fuel filter are fitted correctly. Check under the fuel shutoff valve (the black thing middle-right of the image that has 3 pipes) isn't leaking, if it is you'll feel it dripping from the underside.

The system draws diesel up using a vacuum, so you won't really see diesel spurting out, if there is a leak on the intake side it tends to 'suck' air in.

 

[Parrot of Doom]

By the way if you need to get it started today, jack the back end of the car up, and ensure the tank is full of fuel. It'll start soon enough then.

 

[Bolide]

IMO you have another leak on the intake side of the pump

I agree 100%

Nick Froome
www.w124.co.uk

 

[Bolide]

Does a C250TD have an in-tank fuel pump?

Nick Froome
www.w124.co.uk

 

[mymymy]

Thought I'd give an update and see if I can get a bit more advice. I took the car to a garage to have the delivery valve looked at, but for some strange reason it did not seem to be leaking any more. I have run the car for a while now an still no more wetness. Not sure why its stopped happening but I'm not complaining.

anyway, it seems from a few other threads that the main culprit for my not starting uphill is the pre filter o-ring, so I am going to replace that. I have the new o-ring and what I want to know is, is it simply a case of opening up the bolt on the top, removing the pre filter, changing the o-ring, popping the filter back in, putting the bolt back in and then starting it up? Or is there something else I need to be aware of?

I don't know if a C250D has an in tank fuel pump.

Many thanks

Sam

 

[Parrot of Doom]

Yes, that is exactly the procedure, except you should dip the o-ring in a bit of oil to get a better fit.