Prevent. Maint.
 

I wanted to know you guys opinion on replacing such items as electric fuel pumps, fuel pump relays, fuel injectors etc., as part of a preventative maintenance program.
What things would you add to the list and what intervals would you recommend changing them. The reason I am asking because when these items fail then we are at a loss for time which is very valuable. It would seem easier to just replace items on a timetable - like oil and filters. (less often of course) Just wanted your opinions.

Robert Davis

I don't think there is even a basis for replacing relays. You are right about when these things go, your stuck, but that is the nature of electronics. Fuel pumps will give you a heads up, they will become noisy. Though a good way to prevent burning up fuel pumps (if they are in the fuel tank) is to not let your gas level get below 1/4. The gas helps cool the pump, hence less fuel, less cooling. As far as relays, you could buy a brand new one and it could fail inside of a week. Solid state electronics don't have parts that wear, so there is no way of knowing when they are going to fail. Your line of thinking is good, it's just impractical and expensive to start replacing elctronics just for the sake of preventitive maintance.

I think it is impossible to predict when those things are going to fail. Fuel pumps generally give some warning, or become intermittent for a time.
FTR, the fuel pump on my 300E lasted 16 years/200k miles.

I suppose it can't hurt to carry a spare relay...

Replace for known problem area's like the OVP and fuel pump relays for W124.