A while ago it was suggested that it may be possible to overcome the failure of the 561 ECU to operate the fuel pump relay by replacing the (white) L-Jet relay with the (green) K-Jet relay.

This type of relay senses engine rotation internally instead of using the ECU.
The relay fits the same relay base as the (white) L-Jet one but is wired differently.

Reading my latest edition of the UK. V.O.C Technical Driver magazine I found an article by Peter Suchy on how to do just this.
With the permission of Jack Cluer (the editor) I have reproduced the relevant part below.

"First remove fuse one! Then remove the wires from the fuse/relay unit, with a slim spike pushed down between the housing and connector release the barb then push the connector out, you will need to bend the barb back out so that it locks when you refit the connector.

Then put them back as follows making sure they correspond with the numbers on the relay thick blue/yellow wire
to 87b,pink to87, brown to 30.
Run a (blue/red) wire from terminal 15 to to fuse 13. (an igntion controlled source)
Run a ground (black) wire from the negative bus on the fuse box to 31
Run a (red/white) wire from the single Red/white wire on the tach to terminal 31b.

You will now be left with the black/yellow, red and a looped blue/yellow and brown and white wires.

Insulate these and tie them neatly away in the loom where they can accessed if needed.
Tape the wire from the instrument panel firmly to the loom and make sure that all wires are neatly fitted.
This is to prevent the wires pulling out next time you remove the fuse box!

Now refit the relay making sure all the connectors are firmly pushed into the relay base and start the engine!
The relay is now powered by an ignition pulse from the coil when the engine is turned over."

The above is a bit more work than fitting a new ECU but a hell of a lot cheaper and it retains the original safety feature of cutting off the fuel supply if engine rotation ceases.

Colin.

1990 740SE B200E/M47, remote C/Locking.