simon2u

A Starting Problem !! .
= Mercedes 1994 ,C 250 , 5 cylinder ,non turbo , diesel (WDB202) with 260,000 kms . . Never had an issue in previous 6 months . Always started at the turn of the key . Then one morning it wouldn't . Dead as . Tried quick start ether etc , Coughed a bit but just wouldn't start .
Opened a IP line at the injector and turned motor over but could not see any fuel coming out = possible fuel problem ?,
Removed intake manifold , checked glow plugs , tested them . all ok but # 3 glow plug won't screw out . Its stuck fast .Won't move. Am spraying it with CRC penetrant daily hoping some will soak into the join and loosen it . Someone mentioned that this glow plug is probably carboned up inside the chamber and so won't come out . If so is there any way of decarbonising it now or once its running again ? Would running 100% bio-diesel fuel remove this carbon deposit ?.
Next removed fuel lines to check o rings for leaks . Some clear fuel lines had previously been replaced with black ones so couldn't see if there was air bubbles in lines . But the o rings from lifter pump to fuel shut off valve were hardened so a possible source of a leak. Have ordered more o rings and will replace them all once they arrive . No obvious leaks around IP ( injector pump.
Meanwhile I have noticed that the previous owner has re-plumbed some of the fuel lines . They have plumbed the fuel heater and pre-filter out of the fuel system . ie, Instead of the pre-filter hose connecting to the fuel heater/ exchanger , it instead loops from the top of the prefilter to the bottom of it bypassing the fuel heater altogether . When I removed the pre-filter there was no fuel in it ?. I am guessing this was done as a cheap fix to a non functioning heater ? . How can I test if its working ? if its ok should I re-plumb the pre-filter to the fuel heater/exchanger . If the fuel heat/exchanger is by-passed like this atm is it likely to be affecting the performance or life of the engine .
Someone has also put non return valves on the fuel lines going into the fuel cut off valve . Also there is a small online fuel filter been added previously . IT was clean . Is it likely they added non return valves to stop fuel draining out of the system when it was parked up hill ?. I heard the turbo diesels had a problem with this . No obvious fuel leaks anywhere in the engine bay .
If all the o rings were actually ok and its not air in the fuel lines what else could be causing the non start issue ? . Electrical ? This model and year also had a wiring loom issue where the plastic got brittle and fell off , exposing bear wires . I have patched these up where ever possible . No fuses are blown .
Also this model has no way of priming air from the fuel lines except turning over the motor which runs the battery flat eventually . So am considering putting a priming pump in the fuel line , but where is best to add this . Would one of those boat outboard motor squeeze primers do the trick ?.
Any help or advice is certainly most welcome .
Cheers Simon Newbie .

Mike_C250

hi simon, i am in a similar situation. recently come from a 2week holiday in zimbabwe. decided to take my C250 Diesel on this long trip. she performed very well and gave no problems. she did a total of 7500km in 3 weeks.thus to zimbabwe, around zimbabwe and back to cape town. one day i started her in the morning and she woke to life as usual with one turn of the key. i parked her at the office which is 35km away and when i was leaving after 9hours she started and cut off after a few seconds of rough idling. The EDC light has been on since i bought the car (so not much of any warning from it).

i quickly blamed it on the fuel pump and i took it to a diesel mechanic. he told me those pumps hardly ever died and that probably i should check the O rings. i know very little about cars and so i suggested he sort it out and then the quotation came through!!!!!! he says he will begin by changing the O rings for R450 (USD56.25) and if that fails he would work on my fuel line to expel or air for R500 (USD62.25) and if that fails he will redo my pump for R1500 (USD200).

So in my view i need to spend so much because my mechanic cannot isolate the problem? please advise what solution came out of your problem and possible pointers for me to start looking in findng my problem.

My merc still runs, hasn't given real problems and i do not want to give it attention when it stops moving

Mike_C250

just discovered my battery has dead cells! so every time i start it, the diesel already in the filter and engine burns out and the pump cannot spring into life quick enough to push diesel to the engine. My theory anyway! So by then trying to restart after it cuts off i strain the battery till it can't start. mmm so i am buying a new battery and will post if there is a difference on my C250

So yesterday my girl friend had to remove her stillettos and help me push and for the life of these machines you can't push start it (i have the manual)

Kavi

Hi guys, I have recently acquired a W202 C250D - only have the car for two weeks and I it's is giving me trouble. I do not know the history of the vehicle so I have opted to change glow plugs and do service, I tried to start her 3 days ago and she just wouldn't take, I removed intake and checked each glow-plug and they were wet. I cleaned them up and put them back bust still, she won't start. So I've ordered new ones and am awaiting delivery. The EDC light has been on since I purchased the car and I'm also worried about the carbon build-up inside the combustion chamber, can someone plz advise me on how to perhaps check injectors and or remove carbon from inside engine

ngoni

hi everyone, here i am back again...After changing the battery the problem went away. well for two months then she began to start hard again. it got so bad i would swing her for 30 minutes before the engine could come to life with a black and whitish cloud of smoke. i took it in and they recogned it was the glow plugs. i bought after market ones for R130 each before Vat and had the job done for relatively cheap as well by a colleague. The car ran well for about two weeks and woke up one morning completely dead! i kept cranking and she would not start. frustrated we towed it to my colleague's workshop and he said she was not bringing fuel from the tank. so we took out the lifter pump and i bought one from a breaker. We fitted that and the problem wasn't fixed. I literally went through every diesel related forum for that car looking for clues as to what was wrong. the error codes never really gave much info as it only indicated a problem on the IP line.

Anyway, some wrote up on a relay for the glow plugs for one of the older models and i decided to investigate in that direction and i discovered that my whole loom was so degraded i am shocked this car never actually burnt down.

Has anyone done this loom repair before as MB wants R5000 (US$550)to buy and lord knows how much to install. i have inserted pic of degraded loom

ngoni

hi everyone

after i changed the loom, the problem was temporarily fixed. i am currently going through my third set of glow plugs. after every month (just be fore payday) she dies and will swing till battery is empty and will not start. i have done all the research possible i could tell you the diesel line and all its components and problems as well as solutions in my sleep.

i have checked the relay and it gives readings between 11.3 to 11.8volts per glow plug connector from relay. are they suppose to be 11.5v on the dot?

i am now considering buying a block heater to aid the plugs as Cape Town temparatures are dipping but not snow levels.

Anyone with experience who can suggest looking at anything else other than glow plugs, o rings, clear lines, battery, loom etc?

Nkuthalo Moyo

Hi
Have a similar issue, but mine started after I had the diesel pump seals replaced. It cranks but dies after a few seconds. Ever found out what was the cause?

Neil Winfield

I have a Mercedes 2010 ML350 which is giving me issues on start up when the car is cold or sitting over night in warm weather. I wait for the glow light to go out before turning over but it seems to be a long period before starting. Once it has been running and warmed up it will start straight away. The issue happens only when sitting over night. I have had a new battery installed but no difference. Any ideas with this one.

Thanks

Neil.