SLK 250 diesel 2013 not starting after sitting in a garage for 4 years

[Tony Foster]

Hoping some fellow MB owners could help...?

My wife car has been sitting in a heated garage for 4 years and will not start. I have now drained the fuel from the tank and replaced with new fuel. I have also replaced the fuel filter now (the one with the module on it) and lastly removed the air filter.

The vehicle cranks over, however, will not start. I have sprayed some brake cleaner down the air intake and starts straight away then cuts out. They are fuel getting to the fuel rail, however, not passing through the injectors, essentially no fuel getting into the chambers.

And thoughts?

 

[grahamcol]

Hi and welcome.
It seems you've somewhat isolated the source of the problem and l guess it must be either the injectors themselves or something electrical / electronic controlling the injectors. My guess (complete guess) is that the injectors are crudded up. Whether it's possible to clean these l don't know. Good luck and do let us know how you get on. Hopefully you might get more comments / advice on here shortly.

 

[Tony Foster]

Many thanks for your welcome wishes. I do agree, I pulled one of the injectors out, however, there's really nothing you can see. I wonder if the car will still turn over and not supply power to the injectors if the immobilizer is on? I have no idea if that's how the system works...

 

[Mr Greedy]

If you've taken an injector out, it's pretty cheap to get them tested for spray pattern. Around £25 each I think. Might be worth it to rule them out?

 

[grahamcol]

Not sure on the immobiliser but l guess what you've said is a possibility, especially with a diesel.
Hope you get it sorted soon.

 

[Tony Foster]

Many thanks for that information. I have now realised that when cranking the vehicle they are no power to the injectors. I now think it may well be an immobiliser problem. I have tried both keys and replaced the batteries, code it be that the key needs recoded due to the key not being used for four years? If this is the case, can I do this myself? Also, can anyone confirm if the car will still crank if the immobiliser is still on?

 

[Tony Foster]

Ps. The car locks and unlocks fine with the key.

 

[Blobcat]

Many thanks for that information. I have now realised that when cranking the vehicle they are no power to the injectors. I now think it may well be an immobiliser problem. I have tried both keys and replaced the batteries, code it be that the key needs recoded due to the key not being used for four years? If this is the case, can I do this myself? Also, can anyone confirm if the car will still crank if the immobiliser is still on?

The immobiliser doesn't require batteries - there is a chip in the key that receives power from an inductive loop in the steering column.

 

[Tony Foster]

Many thanks for that confirmation Blobcat. Can you think of another reason they are no power at the injectors whilst cranking the vehicle?

 

[EmilysDad]

do diseasals have a crank shaft sensor?

 

[Blobcat]

Many thanks for that confirmation Blobcat. Can you think of another reason they are no power at the injectors whilst cranking the vehicle?

Not immediately - I'd be looking at getting codes read and go from there

do diseasals have a crank shaft sensor?

Yes

 

[Tony Foster]

Many thanks for that. I do have a small code reader and it's not showing any faults. That said, my code reader is very basic.

 

[Blobcat]

Many thanks for that. I do have a small code reader and it's not showing any faults. That said, my code reader is very basic.

The basic ones will only show the basic OBDII codes - you really need an MB specific one for detailed information.

If it is turning over then I expect that the immobiliser has accepted the key - I don't know the full start authorisation however I doubt the car would turn over without the immobiliser being "happy"

 

[supernoodle]

You may have fuel at the rail, but what is the pressure? Until the rail pressure reaches approx 150 bar injections don't get scheduled.

 

[Tony Foster]

Ok Blobcat, that's really helpful. I just didn't know if it would still crank.

Many thanks for your help also, Supernoodle. I wondered if they were air in the system? I'm not sure how you would remove that? My fuel filter has a module on it with a capped pipe, I have turned the ignition on and tried to bleed it that way, however, still not starting.

This is very strange... 30K on the clock with full Mercedes service history stored in a heated garage...

 

[Blobcat]

Ok Blobcat, that's really helpful. I just didn't know if it would still crank.

Many thanks for your help also, Supernoodle. I wondered if they were air in the system? I'm not sure how you would remove that? My fuel filter has a module on it with a capped pipe, I have turned the ignition on and tried to bleed it that way, however, still not starting.

This is very strange... 30K on the clock with full Mercedes service history stored in a heated garage...

Run back tubes going porous was always a favorite on CDI engines, the injectors would rather suck the air from the tubes than diesel from the filter.

 

[Tony Foster]

Right... I had a look at these yesterday. They looked alright, however, that possibly counts for nothing. Still confused to why they are no 12v supply to the injectors whilst cranking...

 

[supernoodle]

Even a basic generic scan tool should have the ability to read rail pressure so you can rule that out.
During crank pressure rise rate should be high, so injections are released as it passes ~150 bar in expectation that pressure at time of injection is at the setpoint, typically 250-300bar.
Common rail Injectors are normally switched on the high side and low side so you won't see anything if they haven't been scheduled by the ECU.
As well as rail pressure requirement injections don't get scheduled unless there has been synchronisation between the crank and cam sensor to detemine phase.
After a lay up I would expect the wet side components (fuel) to be more likely, so concentrate on those first.

 

[Tony Foster]

Many thanks for your information supernoodle, this provides me with a better understanding. In terms of the fuel, I have new fuel as I drained the system through the capped pipe on the fuel filter, this indicates that I have fuel to there. Then I removed the pipe between the fuel rail and the injector and there is fuel there also, so I'm getting fuel right up to the injector. The only thing I did notice is that they are a delay in fuel exiting the fuel rail when cranking, however only for a few seconds. Really not sure where to go from there?

In summary, I am able to crank the vehicle and it does turn over, also the fuel is being supplied to the injectors and the only thing I can see is no power at the injectors. Possible look upon checking the condition of the crank and camshaft sensors...?

 

[ajlsl600]

do diseasals have a crank shaft sensor?

Yes. And if not enough cranking speed it may not trigger power for a start?