89 560sl Fuel Pump Relay Looses Ground
 

Please help!. We have an 89 560SL in our shop that starts and wont run. After car starts, the fuel pump relay opens shutting pumps off. We tried two new fuel pump relays, fuel pumps, and the overvoltage relay and battery are good. The car has been sitting, the customer jumped it, thats what started this mess. Thank You for any help. Karen

An easy way to determine, get an amp meeter thats fused, and bridge terminals 7 & 8 where the fuel pump relay goes. Check to make sure the pumps are working. The pumps should be drawing 6-10 amps, if more, you have a plugged filter or bad pumps. If the pumps dont come on at all, check the wiring, after you see if you have power. Let us know

Jump started?
 

Possibly damaged OVP over voltage protection relay? Have never seen that affect fuel delivery though.