[adamcockburn1962]

Hi Folks,

So I have just replaced my Fuel Pump on my SLK 200 R171. Not an easy job smelly and messy too.
The original problem was the car would turn over on the key but not fire up. No fuel at the engine at all. The Merc diagnostic showed nothing wrong at all. No Faults ? Strange indeed. The Relay and Fuse were in working order and I could get power to the fuel tank and fuel pump ?
After about an hour of stripping out the rear boot I came across the fuel tank. The fuel pump is located inside the fuel tank, yes you heard me correctly....Didn't the Germans learn anything when the Hindenburg exploded ? Oh well apparently you can pass 12 volts through petrol without being horribly burned at the stake...
So to continue....I removed the FUEL FILTER / FUEL PRESSIURE REGULATOR which is the first part of the fuel tank that you will see. I did replace with a new one as I did think this could be blocked somehow. It was not that part. Then reaching inside the fuel tank on the right hand side at the very bottom of the tank is an assembly with TWO latch catches. Once released you can pull the FUEL PUMP assembly out. Take care of the wiring. I did check the wiring with a volt meter. All was giving a nice 12 volts. As the ignition key is turned you will get a reading meaning the fuel pump has voltage to work. Then I removed the fuel pump and bench tested it...Amazingly it worked just fine??? But after a while stopped, spluttered and died. Obviously an intermittent fault. So I took the assembly apart and carefully replaced the Fuel Pump....BTW it is know as three different things depending on who you talk to. 1. A Fuel Feeder (its correct name) 2. A Fuel Sender and 3. A Fuel Pump (My favourite name) Part numbers vary too and you will find it totally confusing when trying to order this part. I do advocate replacing with a new part and not used since it took over an hour to strip out and get to this vital part.
I replaced the pump, careful of the wiring and position to refit and hey presto a working SLK R171. Please note the older R170 cars have the fuel pump located outside the fuel tank and are much easier to replace.

Have fun, if you need any advice then message me. Happy Days !

Miles 24th January 2023.

 

[Rick_In_Tas]

Nice write up, Miles.

If I think back to my flying days, I recall an instructor telling us that you can't actually set fire to raw petrol, it's the petrol vapours which cause the explosion. I didn't have the nerve to risk one of Her Majesty's aircraft experimenting!