1986 560 Sel

[surgicalpro]

I inherit my mom's 1986 560 SEL with 80,000 miles :-) The car sat for almost a year. The car start right up every morning but after it seats for awhile it's very hard to get it running again. Could this be (Fuel Pressure Regulator, Fuel Accumulator, Fuel Filter?) Thank you for any advise!!!!

[JPutt]

I'm more of a diesel guy but I would start with the fuel filter and make sure you got some good new fuel in the tank. Old gas can cause problems. Injector/fuel system cleaner wouldn't be a bad idea either. If this does't help then you probably need to look further into the fuel pump, pressure regulator, etc. and an electrical system tune up, spark plugs, timing, etc.

I bet its a nice car with just 80,000 on it.

Good luck, John

[surgicalpro]

I have replace the distriburor cap, rotor, spark plugs and spark cable, fuel pump relay and overload relay, new fuel filter and fuel pressure regulator...The car seem to have a problem in the wire harness plug for the fuel pump relay or overload relay. Sometimes the car start right up and run great for awhile and then very hard to start or no start at all. I took reading to the fuel pump when this was happening and have 0 volts going into it. I by-pass the relay and applied 12 DC volts straight to both fuel pumps and both work just fine. Thereafter, I put the old fuel pump relay and overload relay and the car started right up..but again after awhile hard to start again. Does any one have the voltage reading for all pins connectors for the FPR and OLR? Could I be experiencing a ground problem or a faulty wiring harness?
Thanks in advance to any help!!!!

[marlinspike]

The fuel pump relays have a tendency to go bad (well...after 20 years or so). Combine that with the fact that it worked fine when you bypassed it, I would start by replacing the fuel pump relay (IIRC they can be gotten from an MB dealer for less than $150).

[jrrr3]

I inherit my mom's 1986 560 SEL with 80,000 miles :-) The car sat for almost a year. The car start right up every morning but after it seats for awhile it's very hard to get it running again. Could this be (Fuel Pressure Regulator, Fuel Accumulator, Fuel Filter?) Thank you for any advise!!!!

I had the same prob in my 420 sel I replace the vac connetor that where old and it started running fine