Cdi won't start when hot...

[johnjohn_98]

When cold my C220cdi starts within a second of turning over, but after parking for a few minutes (after warming up) it will start but only run for about one second before spluttering to a halt. it then takes six full starting attempts before creeping back to life and then being fine.

So far:
- new injectors
- new pipe mechanical pump to filter
- new o ring on both ends of pipe from mechanical pump to rail
- new white washer thing on pipe by mechanical pump

Where else do I look, I still have my air bubble in the pipe from the "thingy in the inlet manifold" to the the fuel filter too. But this hot starting business is getting old.. (I still don't understand why it gets better when it's cold again)

 

[jgevers]

I would check the rail pressure during the non start by means of diagnostic computer. From the top of my head it should have at least 250 bar during cranking in order to start. If the pressure regulator in the high pressure pump sticks or the o ring around the regulator fails, it is possible for the pressure not to build up. Normally coincides with a 'low pressure' fault code.

Good luck

 

[zishan03]

My dad had a similar problem on his CLK320 and it was the crank positioning sensor or something like that. Basically he would drive for a while then the car would just drop revs and cut out and nt start back up again. Once the car had cooled down it would start again. The problem was something to do with the sensor overheating and giving false readings or something like that. I'm not sure if it will be the same with your car but it is worth a look.


Hope this helps.

Zishan

 

[Dieselman]

It could be the rail pressure sensor giving a low reading when hot.

 

[johnjohn_98]

Now thoroughly confused...

Last night when I got home I decided to watch for myself what happened.

When I turned the engine off immediately there appeared a big air bubble in the pipe leading to the filter. So the air has to be coming in from the filter right?

I removed this pipe (and heard a nice gurgling noise from the thing* on the manifold) cleaned the o rings (I've used my stock of five so I'll need more) and put it back. Predictably the engine was a complete bastard to restart, but eventually it did.

This morning it started immediately...how? It must have filled with air overnight, I know that just turning the ignition on isn't enough to refill the pipes (as it takes the engine turning over to do that).

I have ordered a new fuel filter canister and pipe and will put them on on Saturday and let you know what happens. Meanwhile, any ideas why?

* henceforth to be known as the fuel heat exchanger

 

[johnjohn_98]

So far...

While collecting the new pipe & filter I asked the service department what they thought and they surprised me by saying: a) heat exchanger fails, not on this model, but they've done quite a few on other cdis and b) MAS, apparently it's not used when the engine is started and it's cold, but it is otherwise and that could be leaning the mixture when there is air around, so it stalls...

Anyway I replaced the filter, although I did see that the old canister was fine, but the third party filter's rubber seal was nowhere near the height of MB. I replaced the pipe and it was a very tight fit. I took out the MAS and gave it a good clean and blow-through.

Now all back together I see I still have a large roving bubble, time will tell on that one, but so far it has started every time.

I don't want to think it was the MAS all the time...

 

[johnjohn_98]

Done?

Well it could be the new filter and pipe, or it could be the MAS, who can tell - but it does seem happy starting from warm now. It's hard to sit and let it start and idle without trying to keep it alive with the throttle, which probably points to the MAS doesn't it?

Oh well, hopefully the cleaning has made it happy again, meanwhile one of my week-old injectors has sprung a leak, so I get to do another one...

 

[Vips]

at least this time, you'll be able to post the pics, so all the non mechanics know what you are writing about, well, me anyway!!!

 

[haggis]

My 220cdi seems to have EXACTLY the same problems as "JohnJohn98" and has been in an MB dealership now for 3 weeks. My wallet has been emptied by £900 and on repeated occaisons when I drive it home having been "fixed" again, it refuses to restart. I am at my wits end!!!
I've had the Injectors checked, Fuel regulator changed, FUEL RAIL changed and crankshaft position sensor changed. Dealership say they WERE faulty but car still won't start!!!
Is this a clue? (I'm a retired electronics technician)
NOTE:- When I recharge the battery FULLY (13 volts) overnight, the car almost restarts IMMEDIATELY, not even after 2 or 3 turns, and this can be following a complete failure to restart the previous day following a short or long journey. This means (to me) that the problem is NOT fuel/rail-pressure/injector/ related but a faulty switch/relay/sensor somewhere, which is just not making good contact, but when presented with a fully charged battery voltage, the voltage bridges the dirt/corrosion. This shouldn't be rocket science - but I'm planning going to an autoelectrician next, as I can't afford another visit to an authorised dealership.
What's happened to mechanics who used to diagnose problems, and not just replace modules.
This sounds like a tricky problem but used to be the bread & butter of technicians.
Are manuals, wiring diagrams etc available to the likes of an enthusiastic amateur. Many years ago I used to rebuild vintage cars, so I'm fairly competent - but with modern engine management systems I suspect I'd need a computerised diagnostic system
HELP!!

 

[haggis]

In my last message I missed out the word "always"
After failing to restart after 100% of journeys from the MB dealers (or down to the papershop - I just can't afford to stop the engine on any journey), I can flatten the battery trying to restart. However, and this should be a clue, after I recharge the battery overnight it ALWAYS starts immediately, not after a couple of crankshaft turns. Surely the fuel side of things, rail pressure etc must be OK - doesn't it sound electrical?

 

[dava]

On top of the filter is a black valve with in and out pipes fitted, this is held in by two torx screws, these are prone for failing and cause air leaks and drain back. Some how they get damaged when your changing the fuel filter, luckely they are just coppers to by and come with a new seal.
Hope this helps.

 

[Parrot of Doom]

Haggis, going on your suggestion, have you tried reseating and cleaning all the relays and fuses, and also the ECU connectors?

What happens overnight, when you don't charge the battery - does it start first time?

Have you had your battery tested for Ah capacity, and not voltage?

 

[haggis]

Thanks for your suggestions.
I should really have shut-up and stopped talking nonsense. It seemed sensible to me that it was maybe some switch or interlock. Just Wait!!
Found a mechanic/technician that I trust. Without computers or fault codes or engine management speak, he used his eyes!.
He opened the bonnet, said "What's in that tube"? I looked and said "Air". He shrugged his shoulders and said "That's supposed to be diesel!"

Having spent lots of dough at he dealership, I'm insisting that they fix it. You'll never guess what they are looking at now - air in the fuel line!

I've noticed lots in the forum about this problem, so hopefully the dealership will sort it out.

Good old-fashioned diagnostic skills still work - eyes and earsd and a wee bit of experience.

I'll keep you informed. So far the dealership have taken just short of one month to get this car started. The only journeys I have made are to the dealership, where I've parked the car and left them to push it into their workshop - after all it doesn't start.

 

[haggis]

Haggis, going on your suggestion, have you tried reseating and cleaning all the relays and fuses, and also the ECU connectors?

What happens overnight, when you don't charge the battery - does it start first time?

Have you had your battery tested for Ah capacity, and not voltage?

Pushed in all the relays I can find, and resaeted plugs & sockets.
You'll never guess what happens when I don't charge the battery. It doesnt turn over becuase the battery is flat!! I then need the AA with jump leads and/or booster unit.
Battery tested OK.

 

[Parrot of Doom]

So your battery is either being drained by something in the car, or its not being charged while driving.

 

[haggis]

So your battery is either being drained by something in the car, or its not being charged while driving.

Sorry "Parrot of Doom", you haven't quite got the message. The engine will not start - that's the problem!. Sitting in a filling station, feeling stupid, trying to start the engine causes the battery to go flat!! It can take several minutes of cranking on the starter for it to fire. The AA eventually get it started, flattening their battery too, so when I get home the battery needs recharging. In most cases, the following morning, the car starts perfectly - confusing!

I can use the car as normal, and have done for runs of over 500 miles - as long as I don't stop the engine - so I get some odd looks in car parks.

Many thanks anyway for your feedback.

 

[haggis]

Well it could be the new filter and pipe, or it could be the MAS, who can tell - but it does seem happy starting from warm now. It's hard to sit and let it start and idle without trying to keep it alive with the throttle, which probably points to the MAS doesn't it?

Oh well, hopefully the cleaning has made it happy again, meanwhile one of my week-old injectors has sprung a leak, so I get to do another one...

My 220CDI was eventually "fixed" by a major Scottish MB dealership fitting a non return valve to the fuel line from the tank.
The "fixed" car then started OK but was down on power by approx 50%, and with more bubbles in the fuel line than a champagne bottle on heat! I'm afraid I'm totally disillusioned with MB having now spent £1,000 and for a fault which is still there (air in the fuel line) and if I remove their non-return-valve the car fails to start 100% when warm. I consider this level of service disgraceful!! Letters of complaint have resulted in them agreeing to limit their bill to £1,000 if they coulkd get it started.
This morning the car failed to start even with MB's £1,000 non-return valve fitted. The AA man took approx 30 minutes to identify that the fuel filter had an inadequate seal and air was being introduced to the fuel line. He showed me the problem, stripped down the fuel filter, cleaned all O-Rings with an oily rag and the car not only burst into life but it had 100% powerf or the first time since January. What he said about my £1,000 bill from MB isn't printable.
To be fair to MB (~!"£$%^&*) they have spent 8 weeks now trying to fix this problem, thus the £1,000 bill. However, during all of their 8 weeks efforts MB have seen the fuel line full of air bubbles but eventually opted for the non-return valve just to get the car started - and hopefully get rid of their customer. Well, they have succeeded with the latter - I will never go back to them. But for one of the largest MB dealers in Scotland to fail to find this problem seems astionishing to me. That an AA man with basic tools, no diagnostics to speak of, can fix a problem in the rain at the roadside, both get the car started and identify the cause of the air filled fuel line says montains for the AA and next to nothing for MB.
The reall issue is that the AA man was a "proper" mechanic who saw the problem and without codes, manuals or courses found it by following his instinct. MB didn't have this - relying on computers, fault codes, spotless workshop floors, "free" coffee for customers, factory backup - so they didn't stand a chance. They did however get my £1,000 !!!

 

[haggis]

Well it could be the new filter and pipe, or it could be the MAS, who can tell - but it does seem happy starting from warm now. It's hard to sit and let it start and idle without trying to keep it alive with the throttle, which probably points to the MAS doesn't it?

Oh well, hopefully the cleaning has made it happy again, meanwhile one of my week-old injectors has sprung a leak, so I get to do another one...

My 220CDI was eventually "fixed" by a major Scottish MB dealership fitting a non return valve to the fuel line from the tank.
The "fixed" car then started OK but was down on power by approx 50%, and with more bubbles in the fuel line than a champagne bottle on heat! I'm afraid I'm totally disillusioned with MB having now spent £1,000 and for a fault which is still there (air in the fuel line) and if I remove their non-return-valve the car fails to start 100% when warm. I consider this level of service disgraceful!! Letters of complaint have resulted in them agreeing to limit their bill to £1,000 if they coulkd get it started.
This morning the car failed to start even with MB's £1,000 non-return valve fitted. The AA man took approx 30 minutes to identify that the fuel filter had an inadequate seal and air was being introduced to the fuel line. He showed me the problem, stripped down the fuel filter, cleaned all O-Rings with an oily rag and the car not only burst into life but it had 100% powerf or the first time since January. What he said about my £1,000 bill from MB isn't printable.
To be fair to MB (~!"£$%^&*) they have spent 8 weeks now trying to fix this problem, thus the £1,000 bill. However, during all of their 8 weeks efforts MB have seen the fuel line full of air bubbles but eventually opted for the non-return valve just to get the car started - and hopefully get rid of their customer. Well, they have succeeded with the latter - I will never go back to them. But for one of the largest MB dealers in Scotland to fail to find this problem seems astionishing to me. That an AA man with basic tools, no diagnostics to speak of, can fix a problem in the rain at the roadside, both get the car started and identify the cause of the air filled fuel line says montains for the AA and next to nothing for MB.
The reall issue is that the AA man was a "proper" mechanic who saw the problem and without codes, manuals or courses found it by following his instinct. MB didn't have this - relying on computers, fault codes, spotless workshop floors, "free" coffee for customers, factory backup - so they didn't stand a chance. They did however get my £1,000 !!!

 

[Dieselman]

The reall issue is that the AA man was a "proper" mechanic who saw the problem and without codes, manuals or courses found it by following his instinct. MB didn't have this - relying on computers, fault codes, spotless workshop floors, "free" coffee for customers, factory backup - so they didn't stand a chance. They did however get my £1,000 !!!

Well, it sounds like you need it back, maybe through the small claims court if necessary. They have charged you for a service that you didn't get.

Sounds like a dead easy fault.
Look at the fuel lines and see bubbles after filter but not before. Hmm, wonder where the leak is.??

 

[fredfloggle]

My 220CDI was eventually "fixed" by a major Scottish MB dealership fitting a non return valve to the fuel line from the tank.
The "fixed" car then started OK but was down on power by approx 50%, and with more bubbles in the fuel line than a champagne bottle on heat! I'm afraid I'm totally disillusioned with MB having now spent £1,000 and for a fault which is still there (air in the fuel line) and if I remove their non-return-valve the car fails to start 100% when warm. I consider this level of service disgraceful!! Letters of complaint have resulted in them agreeing to limit their bill to £1,000 if they coulkd get it started.
This morning the car failed to start even with MB's £1,000 non-return valve fitted. The AA man took approx 30 minutes to identify that the fuel filter had an inadequate seal and air was being introduced to the fuel line. He showed me the problem, stripped down the fuel filter, cleaned all O-Rings with an oily rag and the car not only burst into life but it had 100% powerf or the first time since January. What he said about my £1,000 bill from MB isn't printable.
To be fair to MB (~!"£$%^&*) they have spent 8 weeks now trying to fix this problem, thus the £1,000 bill. However, during all of their 8 weeks efforts MB have seen the fuel line full of air bubbles but eventually opted for the non-return valve just to get the car started - and hopefully get rid of their customer. Well, they have succeeded with the latter - I will never go back to them. But for one of the largest MB dealers in Scotland to fail to find this problem seems astionishing to me. That an AA man with basic tools, no diagnostics to speak of, can fix a problem in the rain at the roadside, both get the car started and identify the cause of the air filled fuel line says montains for the AA and next to nothing for MB.
The reall issue is that the AA man was a "proper" mechanic who saw the problem and without codes, manuals or courses found it by following his instinct. MB didn't have this - relying on computers, fault codes, spotless workshop floors, "free" coffee for customers, factory backup - so they didn't stand a chance. They did however get my £1,000 !!!

Get your money back - I was told that MB technicians are the best of the best , 100% competent and that to suggest otherwise was completely wrong . What you have posted suggests that they don't know their arms from their earholes , a problem that a normal agricultural mechanic would have found and sorted with his eyes shut . With a very few exceptions these guys aren't technicians or mechanics , they look at STAR and are capable of swapping components (just) .

As for free coffee - I hope you had plenty , could have cost £1000 a cup !