My 1994 e320 has started intermittently cutting out due to interrupted electrical supply to the fuel pump. I have checked the Fuel Pump and replaced the Fuel Pump Relay with a brand new one, but to no avail. The fuel pump will run perfectly, then suddenly loses its power supply and the engine obviously won't start again until, for no apparent reason, the power supply is restored and everything is back to normal for a short time. What else can I check? E.g. is there a fuse anywhere (additional to the fuse on the top of the relay) that might need its contacts cleaned?
grober
MB Master
Aftermarket alarm immobiliser failure??? ps there is no fuse on top of the fuel pump relay just the OVP one
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Both the fuel pump and OVP relays are essential to the fuel pump working.
kth286
MB Enthusiast
those OVP relays need the circuit board looked at for dry solder joint, then solder and it will be fixed.
OVP = over voltage protection.
It is found behind relay cover in bulkhead - has fuse on top.
OVP = over voltage protection.
It is found behind relay cover in bulkhead - has fuse on top.
Thanks, Graeme. That's a useful thought about the alarm. There was one already fitted when I bought the vehicle. I'll see if I can trace its connections.
But I'm now confused about the relay. There are 3 behind the battery in my car - the 6zyl kickdown one, the tall OVP one (0005406745), and the green fuel pump one which definitely has a fuse inserted on the top of it. It is this green one that I replaced. Incidentally I notice that when the car is running the OVP relay is warm to the touch - perhaps this is normal?
Annoyingly the car is running perfectly at the moment, but pretty-much unusable because I just don't know when it's going to stop again!
Albert
Thanks for that. I have just noticed that the OVP relay is warm to the touch when the car is running - Is that a sign of what you are talking about or is it normal?
Thanks again for that. Further to my last post I removed the OVP Relay and opened it to find that the plastic insulation card was quite burned at one point. I have decided the best thing is just to replace with a new OVP Relay. Thanks for your help
I have now replaced the OVP Relay and this seems to have solved the problem. Many thanks!
