Hi Guy's

I have an 1989 300SE that wont start, I knoe the problem is fuel as I can't get any at the pipes.

1. Does the pump have arelay, where is it, can it be tested?

2. The car is reversed up to a wall so I can't get under the back, is the pump over the axle

3. Has anyone got a pump just in case


Thanks


Tom

 

1) The pump do have a relay. It's in the engine compartment right behind the firewall. Black retangular box fuse. Looking from the front of the engine compartment to the back, it is the one that is the left side on the driver side. (the right one is for the AC and then you have overload protection relay (clear case with red or orange fuse)) If that relay go out, the pumps wont work and you'll get a no start. Not exspensive to replace and easy DIY. Sometimes a short develops where if you tap it or wiggle it, it will kick in. You can turn the car on and fiddle with the relay and see if the pumps turn on. There is also word on "jumping" the relay to test it but I never tried that method nor know the details of it.

2)You are correct. It's on the passenger side and or the opposite side of the exhaust under the axle. Real easy to get to.

3) no I dont have an extra pump, only the busted one that I wouldnt give to my worse enemy. But if you must get a replacement pump, make sure it's the proper flow rate. Usually it's a good bet to go with Bosch as the OEM.


With this, as far as parts, relay is cheapest, then pump. Oh by the way, do the 300SE have one or two pumps? I cant remember off the top of my head. If it has two pumps (as do the 420 and 560) and all of a sudden both of them stop working at the same time then most of the time it's the relay. If one is giving you problems, then it's probably the pump. Oh yeah another thing to do when you can is check the pump wiring. Sometimes I seen them fray, break, or come loose.