Cant find my hp fuel pump

[Johnkarl]

Hello everyone, I own a c220 cdi and i have looked through loads of videos on YouTube looking for the location of the high pressure fuel pump on my engine, I have seen loads but the fuel pump on these engines are at the front, no fuel pump on mine in that location, anyone have any idea where to look, bought this as a none runner

 

[alecmascot]

Assming it's an OM651, the HP pump is gear driven on the rear of the engine. RHS looking from the front.

edit :

https://mymotorlist.com/wp-content/uploads/2021/08/ruk-om651.pdf

 

[Johnkarl]

I think that you are correct, will this pump need timing up or is it plug and play, cheers

 

[alecmascot]

will this pump need timing up or is it plug and play

It's common rail. No pump timing required. You need a Scan tool to read the pressure.

 

[mersum1es]

In fact some gear driven HP pumps have timing mark (I have posted a WIS document somewhere), At least OM642 has it, not sure OM651 pump... It¨s not big issue, probably your car will run ok even it is not 'on time', like said its common rail. Probably timing has been made because there is some pressure wave interference at some rpm, and they want decrease effect by correct timing.

 

[Supernoodle]

In fact some gear driven HP pumps have timing mark (I have posted a WIS document somewhere), At least OM642 has it, not sure OM651 pump... It¨s not big issue, probably your car will run ok even it is not 'on time', like said its common rail. Probably timing has been made because there is some pressure wave interference at some rpm, and they want decrease effect by correct timing.

Correct, common rail pumps usually are timed so you don't have a pumping stroke coincidental with where you'd normally inject otherwise the rail pressure read at the last interrupt will be wrong.
Also don't want the pump stroke happening at the same time as other crank loads, though that's more of an issue for belt driven pumps

And yes, it will ok regardless of timing.

Note, there are some pumps that use something called a digital inlet valve rather than a quantity control valve. These valves are controlled by ECU to open just before pump inlet stroke. These will not work if not timed. AFAIK they are not used on Mercedes though.