K click 8/8 I have a wire vs Low flying article

[GF04RCE]

Hi, I have done what many before me have done and cleaned out the solenoid, cleaned and changed HT leads etc. in a hope of getting rid of the inconsistent starting non-starting problems.

 

So its time for revilla's Low Flying K-click relay change modification.

 

Problem: 2004 140bhp Roadsport and I seem to have a wire in 8/8 which in the low flying article is show as NC based on Andrews 2003 VVC 160 that the article was based upon. What should I do with this wire?

 

Thanks

 

David

[revilla]

Unfortunately it seems some cars are wired differently to mine. Somebody else found a connection to 8/8 too. Looking at the wiring diagram, if you have a connection to 8/8 then the Main Relay in the MFRU will be in use and I'm afraid that you won't be able to do the modification I described. I did put some fairly heavy disclaimers in the article to make it clear that if your wiring was in any way different to mine, you shouldn't proceed. Is you car EU2 or EU3? I'm just wondering if it is the EU2 engines that are wired differently to my EU3.

[GF04RCE]

EU3, the only difference seams to be that yours is a VVC, but dont understand why that would utilise an extra wire...

 

David M

[revilla]

The odd thing is the Caterham K Series wiring diagram I have doesn't show 8/8 as connected. I'd be interested to know what it is running. NB: The pin numbers I used are consistent with the diagrams from the Haynes manual, but the Caterham diagrams number them differently just to confuse matters!

[GF04RCE]

all the other wires are as per your example, its just one extra one in 8/8, maybe someone will come along with an idea of what it is, and why my car has it and yours doesn't....

 

[Felixgogo]

Yes, I wandered out to the garage with your excellent article, Revilla, and everything matched except this extra brown wire on 8/8. My car is a 2003 build /2004 registered 1.6K Roadsport EU3.

 

I am away from the car now but looking at the wiring diagram this wire is on the larger plug, which I believe is the MFRU Output Plug.

 

http://imageshack.us/a/img703/7519/nuo7.jpg

 

http://imageshack.us/a/img824/5340/gft4.jpg

 

According to this, the wire is electrically common with the ones on P3 and P7.

 

I don't have the article here with me, so I can't tell if this wire if therefore needed or not.

 

Cheers

Ian

[revilla]

Unfortunately Caterham use a different system for numbering the pins of the plugs to that user by Haynes, so the one which Haynes and my article call 8/8 is not the one marked as 8 on that diagram. I'd have to have a look again to see which pin it is on the Caterham diagram, but it is shown as not connected. Correct me if I'm wrong but I think on your car, if you count the total number of wires shown going to the MFRU output plug on the wiring diagram and then count them on the car you'll find you have one more which isn't on the diagram. It's a switched output from the main relay, which in my car and according to the diagram is unused. I wish I knew what that wire went to because unless you have some electrical system which I don't have, we should be able to power it from somewhere else (ie. just wire it to whatever powers that system in my car). If anyone with a wire on 8/8 wants to come over to mine one weekend I'll have a look to see if I can trace where it goes, although it might be a tricky job to trace it through the loom. Not for the next couple of weekends though, I've got my work cut out putting my engine back together from the enormous jigsaw of parts in my garage after a head gasket failure. On the off chance, I'll ask Mucus72 if he can check his car to see if 8/8 is wired as his car is almost identical to mine but non-VVC, and he lives about 4 minutes drive away.

[Felixgogo]

😳 eeek! Sorry I didn't mean to make this more complicated, many apologies.

 

I had not realised that the Haynes manual and the Caterham Manual used different numbering schemes in their wiring diagrams.

 

I had toyed with the idea of adapting an old MFRU, cutting the sockets out and making a small small loom to the new relays, so they could be plugged straight in, in place of the old MFRU. This would be reversible.

 

But your method is certainly more elegant.

[Mucus72]

Hi. I checked my MFRU yesterday. For reference my car is a non-VVC standard 2003 SV 1.6 K EU3 Supersport. Andrew asked above if I could check 8/8. My configuration is identical to Andrew's Low Flying article and I have no wire in 8/8.

 

Edited by - Mucus72 on 18 Aug 2013 08:38:42

[GF04RCE]

The plot thickens, what is this elusive extra wire, where does it go, what does it do?

 

I am tempted to cut it and see if anything stops working, although my starting is so unpredictable at the moment I am not sure I Would determine anything conclusive....

 

Might be time to speak to Caterham?

 

David M

[GF04RCE]

Just noticed, from the examples that the SV's don't seem to have the extra wire

 

Extra Wire in 8/8

Me 2003/04 140bhp 1.8 Roadsport EU3

Felixgogo 2003/04 1.6 Roadsport EU3

 

No wire in 8/8

Mucus72 2003 1.6 Supersport EU3 SV

Revilla 2003/04 VVC 1.8 Roadsport 160bhp SV

 

Can't imagine what the difference being an SV would be, but it would be good to get some more examples... Bottom right hand connection of the larger connector into the MFRU relays on top of the ECU. Brown wire with I think a blue stripe....

 

Also interesting we all seem to have cars of the same age

 

David M

 

[Stationary M25 Traveller]

2002 Roadsport SV 160 VVC ..... nothing in lower right hand corner of plug

[Jonathan Kay]

Quoting GF04RCE: 

I am tempted to cut it and see if anything stops working, although my starting is so unpredictable at the moment I am not sure I Would determine anything conclusive....

(ignore the advert)

 

Jonathan

 

Edited by - Jonathan Kay on 18 Aug 2013 10:14:36

[GF04RCE]

Jonathan..... great clip

[revilla]

When I get chance (probably not today, spent all day yesterday working on the car and promised to take the kids out today) I'll do some more investigation to see if I can get the bottom of this. The offending wire is clearly a +12v supply to something, switched by the main relay. The main relay is controlled by ECU pin 4 in the Haynes diagrams (which Caterham helpfully refer to as Pin 54 in their digrams) which is referred to as "Main Relay Control" so no great help. However the Haynes manual does say it used to power the coils and injectors. I'll have another look at the wiring. If it turns out that the coil packs and injectors have a common positive feed and the ECU switches them to ground, that will be what it is. I can then look where that positive feed is taken from on my car and advise further.

[revilla]

PS: Don't cut the wire! Can't imagine it will run very well without ignition or injection!

[revilla]

I've had a very quick look at the Caterham wiring diagram and the MG TF diagram and compared the two. I think I understand what is going on with the extra wire and if I'm right then there is a really simple fix to allow my mod to work with the extra 8/8 wire. I will do some more checking tomorrow and try to post a full explanation with diagrams.

[GF04RCE]

Great News Revilla, look forward to it, any clue as to why some have it and others don't....

 

Big thanks for your diligence from all us K Clickers

[CliffC]

GF04RCE/Revilla

 

I also have the Click and my is an SV 1.8 and it has the additional 8/8 brown/blue cable to the MFRU. So I did not install the Revilla mod but used the one in the Alcester racing web page.

 

It is pretty simple to do but.....when I installed it, the car would not start. It was if I had created the K click.

 

As I had not cut any cables I put it all back as normal and it started first time. I still have the click on occasions but clearly the Alcester Racing relay mod does not work on my car.

I'd be interested if you manage to find a solution

Thanks

Cliff

[GF04RCE]

Well that blows my SV theory, although it didn't make sense anyway..... I might give CC a call this morning just to understand why some cars have it and some don't....

 

David M

[revilla]

OK so here is my latest thinking ...

 

According to the MGTF wiring diagrams taken from RAVE (i.e. to confirm what Rover originally intended to run off pin 8/8) I can see the Main Relay in the MFRU being controlled by ECU pin 54 via a White/Pink wire (matches Caterham wiring) and switching a 30A fused +12V supply from the battery through to the following ...

 

ECU Pin 19 (Believe Input, Confirms Main Relay Engaged to ECU)

Purge Control Valve (Not UK Models)

4 Injectors

2 Coil Packs

2 VVC Solenoids (VVC Models Only)

Lambda Sensor Pin 4

Exhaust Gas Recirculation Valve (Not Used)

Cam Sensor Pin 1

 

... each of which is then controlled by the ECU by grounding the other terminal.

 

According to the Caterham K-Series wiring diagram, every single one of these is either not used in the Caterham installation or is connected directly to the battery +12V via ECU fuse number 14, 30A (as above).

 

So it would appear that according to the wiring diagram, and at least on some cars (e.g. mine) Caterham have for some reason simply done away with Main Relay control and wired everything permanently live to the ECU fuse.

 

I suspect that the relay is there to isolate all of the above items from the supply when the engine is not running, possibly to render them safe to work on without disconnecting the battery, possibly to avoid any small leakage through these components back to earth through the ECU output transistors which could place a small drain on the battery when not running, possibly for some other reason that I haven't thought of - the point is however that everything seems to work absolutely fine when these are all wired directly to the ECU fuse rather than through a relay. Including ECU Pin 19 will tell the ECU that the Main Relay is engaged and it will run everything as normal.

 

My guess would be that, as all of the relays in the MFRU appear to be of similar construction and that the main relay is carrying a current of the order of 30A (judging by the fuse rating) which is similar to that carried by the often unreliable starter relay, I would imagine that the main relay will also have been found to give problems on some cars (there is at least one recent thread where the fuel pump relay has played up too), so I guess by changing the wiring to take this out of the circuit Caterham have effectively done a "relay mod" of their own for reliability. Why it appears only on some cars, even of the same age, I have no idea, unless of course Caterham made the change but still had stocks of old looms.

 

OK so what does this mean for my modification? Well if correct, it would actually mean that there is a very neat solution. In my original article I describe how the brown wire from ECU pin 8/1 is no longer used and should be insulated and left disconnected. This wire carries the 30A +12V supply from ECU fuse 14. So instead of simply leaving it disconnected, you could cut this wire and the extra wire that leads to pin 8/8 and just join the two ends together with a crimp connector. As far as I can see, this should effectively convert your electrical system to work the same way as mine. Basically where I have described using a crimp connector to safely blank off this wire, you would just poke the extra wire into the other end of the crimp.

 

Now before people go rushing off to chop their wires, I would just like to say this: I tested the original modification on my own car before telling the rest of the world about it, and when I did publish I was very careful to say that people shouldn't try it if their cars were at all different, as this was moving into untested territory and I didn't want to be responsible for people making changes to their electrics on my advice which had not been tested. In this case however, I am not able to test it on my own car as mine does not have the extra wire, so it's a different ballgame. I cannot 100% guarantee that my analysis is correct, although I can't see anything wrong with it.

 

What I would suggest is that one brave soul gives it a try and reports back before everyone else jumps. GF40RCE - Although I live in Loughborough I work in Grantham, I believe you are in Peterborough so only about 40 minutes down the A1 for me. If you would like I would be happy to come down one evening after work with my tools and multimeter and have a look at it with you?

 

I would suggest the following:

 

1) A thorough check with a multimeter to make sure the extra wire is at least feeding the items which I think it is, as described above, to confirm that we are on the right tracks. If so we know that these items can be connected to +12V without damage, so ...

 

2) Temporarily splicing the extra wire into one of the brown supply wires, without doing any of the other changes. We could do this in a way which was reversible if we didn't get the results we expected.

 

3) Checking the engine to make sure that everything seems to be running as it should be, i.e. the fuel pump primes (so the other relay in the MFRU is still doing its job), the engine runs (so injectors and coils firing), nothing funny happens when starting up or shutting down (doesn't run on after switching off) etc.

 

4) If all of the above checks out, we do the mod. If not, we reconnect the extra wire and think again.

 

I have to be honest, I'm no expert and I'm not an electrical professional, I'm just offering this as my personal idea for a helpful solution and I'm happy to work alongside an owner in trying this out, but only on the basis that the owner accepts the consequences of the fact that I'm just an interested amateur owner trying my honest best. I would also reiterate that there are many possible weaknesses in the starter circuit and that this mod relieves only one of them, albeit a well known likely culprit, but the possibility exists that we could complete the mod correctly and still be left with a K-Click if the real cause is somewhere else.

[charlie_pank]

Hmm, having done lots of things to fix the K-click when I had a K, I have to say that:

 

1. If you understand what you are doing, then you will be able to interpret the step-by-step instructions to make it work in your (or any) car.

 

2. If you don't understand what you are doing and are just blindly following the instructions then it will only work if your car is exactly the same as the one in the instructions.

 

3. The quickest path to understanding what you are doing is probably to have a go, and just make sure that you take enough notes to allow you to return it to its original state if you break it.

 

 

[GF04RCE]

Hi Revilla, YHM ... happy to be the Guinea Pig....

 

David M

[CliffC]

Revilla

I'd be very interested in your findings. Thanks for your efforts

Cliff

 

[Felixgogo]

Yes, I would be most interested too, thanks for this investigation, it is most interesting.

Sorry I'm not in the UK to assist, but let me know if there is anything I can do to help.

 

Cheers

 

Ian