C250td

[John Rodgers]

I am having trouble getting fuel to injectors,I have been Told it could be my injector pump,could this be the case,any other ideas,all lines are clear and no air in them,all I can get is a dribble coming out at injector pipes thanks johnr

 

[Dieselman]

It won't be the main pump, they really can't fail unless catastrophic failure happens.

Is the lift pump pumping Ok, next up would be the stop solenoid then the wiring and ECU.

 

[Terry_]

Can you hear the stop solenoid when switching the ignition on/off?
Crank sensors do fail on these as well

 

[John Rodgers]

Yes the stop sensor is working,
Where are the crank sensors located.thanks johnr

 

[John Rodgers]

Will check lift pump to morrow,thanks johnr

 

[Dieselman]

The crank sensor is mounted into the bell-housing area, but you can measure the output in the diagnostic socket, Pin-13 WRT Gnd, Pin-1.

 

[230K]

Hi

Would the crank shaft position sensor stop this car from injecting?

John has had all the injector pipes and the stop solenoid off and a bottle of diesel going direct into the side of the IP where the stop solenoid goes and still nothing shooting out of the top of the IP.

Is there a K40 relay or something that would stop it too??

Thanks

230K

 

[Terry_]

Well it's a diesel. If it doesn't prevent fuel being injected the motor would run!
It has no spark so the only way to prevent it firing is to strangle it of oxygen or prevent injection.

 

[Dieselman]

Yes and Yes, but the pump needs to have fuel under pressure to be full.

Anything electrical will stop this pump flowing as the rack will move to the STOP position, so shutting off the fuel supply.

 

[230K]

So what to try next then, think the pump filled with diesel from a bottle with a head of pressure though the stop valve solenoid hole eliminates the stop solenoid??? Would you agree?

Next is try the crank position sensor and measure voltage between pins 1 & 13 of the 32 pin diagnostic socket???
It should pulsate as the engine rotates is that it???

230K

 

[230K]

Right we tried a known good cps sensor and no change. Also swapped a known good k40 relay.

I removed the cps from my E 300 TD and she behaved exactly like this c250td is behaving.

Fuel is just over flowing the delivery valves withe the injector pipe removed.

What else can stop her from fuellling??

Help anyone????

What to try next??? The ecu??? Anyone got a known good one????

Feel free to quiz away.... you hopefully will have an idea.

Thanks

230k


230k

Sent from my Nokia 6310i on giffgaff using MBClub UK ;-)

 

[Dieselman]

Without correct power from the ECU the rack moves to the STOP position, hence no fuel flow.

Wiring or ECU would be my first port of call.

Is the ECU definitely getting power. There is a fuse for the injection system.

 

[230K]

How do we check if ecu is getting power??

Interesting thing was stop solenoid was only getting 5 or 6 volts to one of the 4 terminals.
Pins 1 and 13 gave about 0.9v and 2 cranking... the same as my car.

Where is injection fuse?? Fuses everywhere!!

230k

Sent from my Nokia 6310i on giffgaff using MBClub UK ;-)

 

[Dieselman]

F5 is the fuel relay fuse.
+12v enters ECU on pins 37 and 55.

The shutoff solenoid receives power from ECU pin43 (pin 3 on solenoid) and is grounded the other side. (pin 1 solenoid connector)

CKP enters ECU on pins 28 and 20.

 

[230K]

Will


The pin numbers you mention, they are the pin numbers on the ecu??

Thanks,

230k

 

[230K]

Update

Took the connector of the ECU and only two pins were powered up with the ignition switched on.

They were the 2 pins shown in the photos below





Excuse the poor quality photos

Is this right??

Anyone?

Thanks,

230k

 

[Dieselman]

Yes. They are for 300TD, but should be the same, I believe.




^^ What number pins are they? Doesn't sound right as things like the EGR transducer should get power but no active low signal.

 

[230K]

No numbers on the pins. I haven't seen it myself but no reason to doubt John, he even looked with a magnfying glass for numbers.
Not familiar with the egr on the c250td but it can be disconnected without throwing a code and they dont have a maf either.

Keep the comments coming, we will get her going. ....

Thanks

230k

Sent from my Nokia 6310i on giffgaff using MBClub UK ;-)

 

[neilrr]

How old is the fuel filter?

 

[John Rodgers]

Filter is a almost new