Fault mfru? - no power to starter motor

[les]

Just as I though we were finished from the winter refresh and the 'sabrehead' head was re-installed, I'm not able to start the engine. No power from to the starter itself, although the starter and solenoid will fire if I put the battery directly on the terminals. With the help from seloc I have got the (I think) the pin outs from the multifunction relay unit and I will test this later on this evening. I can hear the fuel pump prime so some power is getting through the relay itself. Fuses all look and test ok (the ones that I have found) However the mfru doesn't have any part number on the unit itself and is a different shape to the later revisions, does anyone know if its directly compatible? I managed to get a later version from a scrapped TF but still no luck. Anyone got any ideas? The S1 was registered in Sept 96 and is 63 off the production line

After a quick google I found this on a caterham site showing the differences in shape. Their write up suggested that the mfru was indeed different in which case I could be screwed Just want the old girl back on the road for the summer






Thanks in advance

[robin]

I have never heard of the MFRU in the S1 being different on older models. There are some other parts that come in very similar plastic boxes with the same set of loom connectors, and these obviously aren't what you need. I suspect that the old MFRU they talk about relates to point in time earlier than Lotus use of the K.

I've just checked the model history and no mention of it. What did change was the way the ECU is powered - on your car the ECU power comes off the main +12V stud on the starter, along with the alternator wire; on later cars there are chunky brown wires running straight to the battery for the ECU power supply. Not that this matters much, but it's the only relevant change that happened after your car.

Can you confirm that the +12v stud on the back of the starter is live and that you're taking a +12v feed to the wee spade terminal to make the starter turn? Does the engine then start and run?

When you turn and release the ignition key can you hear the relay at the back going click?

Cheers,
Robin

[robin]

BTW, the start relay is double immobilised.

Assuming the 40A fuse is in tact then the +ve side of the coil is driven from the ignition key via the immobiliser relay - note this circuit is independent from the fuel pump immobiliser, so just 'cos the fuel pump runs does not mean that this circuit is functioning. The -ve side of the start relay is driven from the immobiliser also.

So of all the circuits that might not be working, this is the trickiest to debug.

I can walk you through the process if you like.

Cheers,
Robin

[les]

Robin,

>>
>>Can you confirm that the +12v stud on the back of the starter is live and that you're taking a +12v feed to the wee spade terminal to make the starter turn? Does the engine then start and run?

Engine turns over but doesnt start (well starts and cuts out very quickly, 2 - 3 secs)

>> When you turn and release the ignition key can you hear the relay at the back going click?

Don't think so

If I ground the black/white strip wire from the relay straight to earth, will this take out (bypass) the lucas alarm?/imobiliser?