240 Fuel Pump Relay

[rtbcomp]

Hope this can be of help to some of you.

The following refers to my 240 SE Estate, UK model, it runs on petrol and it's red.

This is the circuit as far as I can tell, my Haynes manual doesn't even resemble what I have on my car.

If I've got anything wrong or left any gaps, please add your comments!

1992 240 SE Fuel Pump Relay 01.jpg

When the ignition is switched on both relays close and power is applied to both pumps (one is in the tank and the other isn't). I'm not sure which pump is fed from which relay.

I'm guessing the ECU controls the relays by providing them with a ground path.

If the engine isn't cranked for about a second (or it stops due to a crash or something) relay 2 drops, switching that pump off.

You can test the circuit with a test lamp as follows:

1) connect one of the test leads to the chassis and the other to the LH end of fuse 6, the lamp should light, if not check the clips, leads and bulb.

2) connect the test lead to the RHS of Fuse 6, if it doesn't light now check the fuse (6), it may have blown or not connecting with its holder correctly. This fuse can run warm which may cause it to distort, weaken the spring connector of the holder or make the contacts corrode.

3) with fuse 6 working move the test lead to the LHS of fuse 4, turn the ignition on (don't try to start the car) and the lamp should light immediately and go out after about a second. If it doesn't light it looks like a faulty relay.

4) if it lights OK repeat the test with the lamp connected to the RHS of fuse 4. If it doesn't light this time give the fuse the same treatment as for fuse 6 above.

5) now you have power to both pumps and if the car still doesn't start something else is wrong.

If you listen carefully you can hear the pumps, they both run for about a second then one of them stops, the other stops when you switch the ignition off.

If you can't hear the pumps it's time to examine the relay.

The relay is fitted to the inside of the bulkhead, behind (or in front really) of the glove box, which has to be removed for access. To do this open the door (of the glovebox) and remove the cross-head screws around the perimeter of the glovebox. Then pull the glovebox towards you, no need to empty it. The little light will remain behind, lit. Pop the light assembly out towards you to extinguish it (this removes its earth).

You can see the relay ahead of you, it's the white plastic thing:-

1992 240 SE Fuel Pump Relay 02.jpg

Simply slide it out of its clip and unplug the connector to remove it.

To remove the cover spread it slightly where it joins the base to release the clips and withdraw the relay complete with its base, you need three hands ideally.