'99 C250 TD W202 with air in fuel line - won't start

[Mol]

I've got 2 C250TD's, and on both I've done 2 things.
1. Replaced all the hoses you showed a pic of in the initial post. There are 6 quick(ish) release hoses, and they are about £40 with all the hoses from a main dealer.
2. I put a non return valve in the feed from the fuel tank. Got it from e-bay I think, under a tenner. The air leak allows all the fuel in the system to run back to the tank, the non-return valve stops that.

This has worked really well, although I had to post the other day about another starting problem

 

[purps]

This is actually my current problem, car is just sat at the garage because they are so busy over Easter, wish I'd had it towed home instead.

I've had the air in the fuel line issue, replaced all the clear lines, o rings, etc and car ran fine for ages (although I have not done the black flexible pipe from the hard lines), but this is issue is another level - there is NO fuel whatsoever getting through, despite lots of cranking. Surely this can't be down to the black hose leaking?

The car literally started fine for work in the morning, and didn't start in the evening when coming home, very sudden.

Cheers,
Matt.

 

[rorf]

Do what Mol has suggested. Early models were even modified with electric valves to prevent fuel syphoning back to the tank.

Actually suprised me tha Mercedes couldn't come up with a better solution - this would never have happened on a Japanese diesel!!

 

[purps]

Thanks for the advice chaps, willing to accept it's a design flaw, but I don't think I should be modifying the design without fixing the initial problem!

There is no fuel whatsoever getting to the engine - I want to solve that before I go putting in valves etc (although if I do replace the black pipe, I think I'll put a priming bulb in, starter motor has had so much abuse since I got this car haha).

Cheers,
Matt.

 

[guydewdney]

Priming valve isnt a bad idea. Mine has it. The stop solenoid can, as sort of mentioned above, also leak from the 'ends'. Requires bravery to take ends off and replace said o rings, which is not in the manual, but us possible, i know, ive done it.

You could save yersen a lot of bother and just buy mine.... Hint. Lol

 

[purps]

Man I really hope it isn't the stop solenoid, as I said it took 3 visits to Merc Medic for them to diagnose that, so I won't be impressed if it's already stuffed! Was only a year or so ago.

 

[guydewdney]

One 10mm spanner and 1 T27 (iirc) torx bit is all thats required - I can get the stop solenoid off in less than five mins with a cool engine. You could buy the tools for less than 20 quid.

remove washer squirty bottle by removing the 10mm spanner size plastic nut on the top

lift bottle up and lay on top of the ABS unit or similar.

pop off fuel pipes x 3 by pushing C shaped white clip in, then pulling pipe. return C clip to pulled out position after.

put torx bit into 1/4" drive ratchet with adaptor. You need a 'long' series of torx bit - about 1" (25mm) long or so. I like to have an extension too on the ratchet. Possible with a 3/8" ratchet but its easier with a diddy one.

undo two screws now easily accessible under manifold. Possibly use a small torch to see what you are doing. One is easy to see - the other isnt so easy, but is at the 'back' of the stop sol. nearest the windscreen.

pull out solenoid towards washer bottle.

replace O ring on short stubby tube. BE CLEAN!!!!! use lint free rags / paper to get this CLEAN! No - cleaner than that.

put everything back together.

If this fails, remove stop sol (need to unplug it too) and get in a vice and remove the end caps - but this is quite difficult. Buy a replacement or silicone sealant the round 'ends' of the stop sol. ?




I genuinely think it took me longer to type this than actually do it.

 

[purps]

Very kind of you to explain in such good detail, but I'm not sure how/why we are leaping to the conclusion that it is the stop solenoid? Is that the only place an air leak can occur that means all the fuel drains completely back to the tank?

The garage won't look at it today so I have the weekend to go try some stuff. I will have a look at the main black hose and fit a primer bulb with valve, trim the ends, change hoseclips, etc. Just being able to draw some fuel from the tank would instantly eliminate an issue at the tank end wouldn't it. Then it can only be something in the engine bay.

Cheers,
Matt.

 

[guydewdney]

Mine did leak from the end of the hard lines. Re clamping fixed it.

 

[darkchild101]

Air in the pipes is the problem I had. End up having to replace feed pipe that goes into prefilter. How hard/easy is it to do?

 

[Dieselman]

Very.

Push in the horseshoe clip, pull the pipe off, ensure clip on new pipe is out, push pipe into socket.

 

[purps]

It was the main black pipe, very perished on the ends - please forgive my extreme amateurism, I should have just done it when I did all the clear pipes/o rings.

Anyway it's fixed now, glad I got some time and managed to sort it before the garage cleared their own backlog! Could have been an expensive bill with them hunting around for the problem.

For anyone who's interested, although it shouldn't be necessary, I did fit a primer bulb just in case I need it to get out of a tight spot should another air leak come along. I also wanted to rule out any blockage at the tank end, so it was handy just to eliminate that possibility before putting the manifold etc back on.

Thank you all for the help and advice, it is much appreciated.

 

[darkchild101]

It was the main black pipe, very perished on the ends - please forgive my extreme amateurism, I should have just done it when I did all the clear pipes/o rings.

Anyway it's fixed now, glad I got some time and managed to sort it before the garage cleared their own backlog! Could have been an expensive bill with them hunting around for the problem.

For anyone who's interested, although it shouldn't be necessary, I did fit a primer bulb just in case I need it to get out of a tight spot should another air leak come along. I also wanted to rule out any blockage at the tank end, so it was handy just to eliminate that possibility before putting the manifold etc back on.

Thank you all for the help and advice, it is much appreciated.

I've got a primer on mine for those times I change filter and it makes it easier to start after it. What sort of clips did you use to secure the primer and what size was it? Mine is 8mm. After removing the exhaust manifold was it easy replacing the black pipe

 

[purps]

Well, I also bought an 8mm bulb, and some 8mm pipe to go with it given that it was the biggest pipe my usual autofactors has, and guess what, I couldn't push it onto the hard lines. Lovely fit with the bulb though haha.

I could have dipped it in some hot water and tried again, but I believe I had read somewhere the standard pipe is 10 mm, so decided to find something else. Closest I could get was 9.5 mm at Halfrauds, and that was absolutely fine.

The bulb came with some little what I call "plier" hose clamps (i.e. you need pliers to get them on and off), but I just used normal jubilee clips everywhere as I already had them.

Once I had removed the inlet manifold, and got the right-sized pipe (or close enough), it's easy peasy. Just ensure the bulb ends up in a place you can reach!

Cheers,
Matt.

 

[Chertishev]

gfdgfdgfdg dgdfgdfg

ñó äæîê êëèíèêà http://sekretpro.ru Peter Nalitch
ýìî óçîðû referatdoki.ru Produzione sanitari di design in ceramica, arredo bagno e accessori
ïîäâðêè twittonator.ru àííà àõìàòîâà

 

[peapod]

I had same problem and after doing all o rings on pipes it persisted. The last job is to change the seals on the delivery oulet valves to the injectors on the fuel pump. It now starts instantly and has done since I did the job a year ago. It is very fiddly and you need special spanner for the unions. I wrote about it at time try seraching for peopod
I tried Oliviers suggestion , glad to hear you are still at it Olivier, to by pass the prefilter but it did not help me. I had qiute a suction in the tank so took the rubber seal off the fuel cap also, but that was not the cause. I must clean the tank vent and put it back! it is just going like a dream 220k starts like a cdi, no kidding providing you wait for the glow light to extinguish.

 

[guydewdney]

My old 250 woukd start literally on the first compression stroke. I did the delivery seals, the stop solenoid main on ring, both on either end of the stop solenoid, all the pipes, the heater was bypassed, the filters o rings all new. Total cost less than 75 quid.

 

[Olivier]

Something over looked is the Leak off pipes. They perish and let air in.

 

[darkchild101]

Something over looked is the Leak off pipes. They perish and let air in.

Which are they

I have got a hand primer/buld on the fuel feed line and it flattens when drving and the engine "gasps" for fuel and stop of "misfires". Really want to keep the bulb in as makes it much easier to start after doing fuel filter change and stuff

 

[Olivier]

The one coming off the injectors, the wee rubber pipes are the leak of pipes.
When you change the fuel filter you need to fill up the new one with fuel, about 0.5 litre, then rev the car to 2500 until its all clear.
You don't need a primer pump.