Possible causes of breakdown

[John Vine]

That sounds like progress!

It suggests that your relays are ok after all. I suspect the relay terminals and the spade connectors they plug into may be in need of a good clean.  Try pulling and re-plugging the relays several times to improve electrical contact.  Also check that the spade connectors themselves are correctly located in their housings.

... diagnostic done on the fusebox/relay ignition system...

I agree.  No doubt your neighbour has a tame auto electrician?

JV

[wild bill]

Yup John he's proper geeky old school and weird. Folicly challenged but with a pony tail and always in black and sporting an AC DC t shirt with a roly on the go  BUT very good

[wild bill]

So there are actually 4 relays and after removing all of them one by one the car starts with none in 

So basically i am back to having absolutely no idea why the car stopped and now no way of finding out. Bl**dy kit cars 

[John Vine]

As I recall, my 1999 1.8K didn't have an ignition relay.  Assuming your chassis harness is still fundamentally K, your discovery makes some sort of sense.

It looks like some detective work is required.  Can you tell us:

What the four relays do?
What year is your car?
Was it EU2 or EU3?
What changes (if any) were made to the engine and chassis looms when the 2.3D was fitted?

JV

 

[Jonathan Kay]

What John says.

I have lots of diagrams with four relays. If you can discover the position and function of as many as possible we can probably work out which loom it is.

Jonathan

 

[wild bill]

Well interestingly it's difficult to find out what they all do due to overlap (it was explained to me and i glazed over because it was beyond my brain functionality) I do know that the bottom one is flashers so i'll try and work out what the other do but perhaps Caterham know?

Car is a 1997 K series originally. EU3 i believe and the only loom changes were the actual plugs/connectors.

The only loose wire is the defunct OP wire as i went mechanical after multiple sensor failures.

[Jonathan Kay]

That should be as below.

Jonathan

 

[SLR No.77]

#31

A 1997 K-Series wound have originally been EU2, if it helps!

Stu.

[wild bill]

So whatever caused the breakdown was not relay related. As the car is now fine and i've effectively done nothing to fix it the whole thing is a mystery. Nothing looks loose that i can see. Other than swapping coil (which didn't resolve) and removing and reinstalling the same relays i've done nothing. 

Thanks for the diagram JK. Stu thanks for the EU clarification. I thought (possibly wrongly) that when i upgraded my car VHPD etc (i did a K series fettle first before going Duratec) that the Emerald ECU was remapped to EU3 by Dave Walker.

 

[Ian Macquarie]

I may have missed it further up the thread - but have you checked the MFRU? Isn't it this, in the engine bay, that contains the Fuel pump relay and main ECU supply relay?

I believe that Revilla has put wiring diagrams and explanations on Blat Chat in the past.

[Jonathan Kay]

I have the MFRU diagrams and the suggested fix if anyone needs them.

Jonathan

[SLR No.77]

Have you checked the main feed into the engine bay for a good contact? For the K-Series it was a heavy (2.5mm?) purple wire linked to a brown near the MFRU, if the connection is dodgy/intermittent it can cause all sorts of confusing issues.

Stu.

[wild bill]

OK I'll check this to see. 

[John Vine]

...but have you checked the MFRU?

Good call!  Concentrating on individual relays, I'd completely overlooked the MFRU as a possible source of the problem. 

I believe that Revilla has put wiring diagrams and explanations on Blat Chat in the past.

There's a veritable mine of information here on the EU2 engine loom, and an informative thread (post #8 on) here.

I guess both of these should help your old school auto electrician...

JV

[wild bill]

Thanks John for the links

[anthony1956]

This sounds like the fuel circuit, yellow with a green line. It runs ... everywhere.

Faults on mine (K R500) were:

inertia switch intermittent connection failure - test by shorting it (the terminals were goosed.)

purple connector as in #37 - should replace it anyway, a "well known" point of failure that connects the engine loom to 12v power. Terminals were goosed.

the "large grey plug" multi connector, my fuel feed supply was intermittent because the yellow/green connector was loose inside i.e. terminal was goosed.

fuse bank connects - terminals were ok. 

Can you hear the pump priming? Sounds like not. If you feed 12v straight to the pump does it work?

I also checked for heat soak damage (loss of conductivity due to hardening of the wire)) where the yellow green runs along the front of the bulkhead with all the other main loom wires, but it was ok.. if I thought a little stiff.

In the end I replaced the entire engine loom (thanks Andrew).

Which reminds me the brown feed wire from the alternator; the connector to the alternator disintegrated upon being touched; however I forget if that is relevant to this problem. 

Anthony

so my trouble was caused by geese ;-)