c class diesel bad starting

[madaboutmymerc]

I have a c250d changed heater plugs (twice) fuel filter, air filter. It takes ages to start and seems to be getting worse, when started its fine. I have been told it is fuel going back to the tank and causing an air lock! I was also told a non return valve can be fitted to cure this. Any help appreciated it is driving me nuts.

 

[wagger]

it will be drawing in air around the plastic fuel pipes between the filter head & the fuel pump (very common)
regards
wagger

 

[madaboutmymerc]

What do I need to do..replace all pipes and unions?

 

[wagger]

the only way is to replace all the plastic fuel pipes together because they get hard & very brittle after a few years, so chances are that in replacing only 1 you will crack/damage 1 or more of the others in doing so.
hope this solves your problem.

 

[madaboutmymerc]

Thanks...I will let you (and everyone else in the forum) know the outcome.

 

[madaboutmymerc]

Garage changed all pipes..still bad starting this morning. I noticed there is fuel drips under a black plastic "cover"!?? on the side of the pump. Anyone know whats under the cover???

 

[sixpack]

Fuel Leaks Etc.

Hi MAD,

The black plastic thing is the fuel shut off module. Its easy to remove, 2 torx bolts. Attached to the pump is a plastic spigot with an O ring on it. On mine the O ring was hard & cracked. Replacing this (& the 5 pipes) cured all my air leak and starting problems. If you need it Ive got a print out of the parts book of this bit, ask if you need it.

Hope this helps
Peter

 

[madaboutmymerc]

Thanks Peter, I have ordered one today and hope to have it fitted on Wednesday or Thursday.......this problem has had 3 garages up the wall for 6 weeks..if they had come onto here they could have sorted it.

 

[jdt]

C 250 diesel bad starting/fuel leak

has anyone else had problems with fuel leaking from the top of injector pump around the serrated heads and collars. Starts as soon as running and stops on switch off, leaks continuously when running. Looks to be similar to sixpack's reply on sun 25 july. Can you please send me a print out of parts book.

Many thanks

David

 

[sixpack]

Fuel leaks

Hi JDT,

Ive never had a leak from the top of the pump like you describe, but looking at my pump, the only things that could leak are the 5 outlet pipes feeding the injectors. Might be a good idea to clean the top of the pump with petrol, let it dry, start up and look closely. Surely all 5 pipes dont leak simul simeul ** together. If you find only one leaks, check its not loose. The torque value for the unions is 11 lb/ft but you need a fancy crows foot spanner to measure it. Note that there are adaptors screwed into the pump top that the unions fit onto. My haynes book shows a picture of them but doesnt give a torque value.

Hope this helps
Peter

 

[jdt]

fuel leak

Thanks for prompt reply. It is the outlet pipes on top, No they dont all leak, looking from rad end 1st leaks a lot, 2nd a bit, 3rd seeps and 4th/5th are dry. They do all start to leak as soon as engine running. they dont leak from the unions but from underneath the locking collars that hold the adaptors. is there an "o"ring or seal in there thats perished or gone brittle. Are the adaptors easy to remove? Do you need a special tool?
Will it be a new pump
Thanks for any help

David

 

[wagger]

the "outlet pipes" are the injector pipes. the piece beneath the union is called the delivery valve. there is a special splined socket available & there is seals under the delivery valves they should be available from any good diesel pump repair shops.

 

[jdt]

thanks for all the info. will see what i can do with it.

 

[madaboutmymerc]

Changed the fuel shut off module car is starting first time again it has 125,000 miles on the clock, a freind of mine has a c180 diesel with about the same miles on it he is getting starting problems too so he is going to change the same part maybe 120,000 miles is the lifetime of these? Thanks for all the help especially sixpack.

 

[alesantana]

Re: Fuel Leaks Etc.

Hi MAD,

The black plastic thing is the fuel shut off module. Its easy to remove, 2 torx bolts. Attached to the pump is a plastic spigot with an O ring on it. On mine the O ring was hard & cracked. Replacing this (& the 5 pipes) cured all my air leak and starting problems. If you need it Ive got a print out of the parts book of this bit, ask if you need it.

Hope this helps
Peter

Sevilla, 19-10-2004

Hello:

I have this starting problem on a C 250 TD 1999, W202. Could you send a print out of the parts.

Thanks,

Alejandro.

 

[madaboutmymerc]

I do not have them print out but peter says he has.. his user name is sixpack.

 

[alesantana]

Thanks for unsering!!!!

I started by changing the 6 clear tubs (pump to filter) now I have to wait.

Alesantana

 

[alesantana]

starting problems

Sevilla, 3-11-2004

Still bad starting. I´m going to change the fuel shut off module next weekend. I will let yuo know.

Alesantana

 

[alesantana]

250 TD bad starting



I changed the fuel shut off module: the car is working OK now.

Alesantana

 

[alesantana]

No,it is not starting yet.

Alesantana.