There's an unknown spare plug in my engine loom ......

[SLR No.77]

Rewiring/recreating my K-Series engine loom, and as well as adding a few extras for future changes (thanks Adrian ) I have a whole section with a connector plug that's not connected to anything. It appears to be routed to both the MFU and ECU plugs and is protected with a heavy rubber sheath, and sits next to the ECU. Is this for diagnostics? Is it superfluous? Any reason to not simply remove it?!!!!

 

Stu.

[Englishmaninwales]

Ive always assumed it's for diagnostics.

[Sigmamark]

Only one! I am running an Emerald and seem to have an engine bay full of things not connected to anything. Because I am a bit OCD about things like that, I did consider dismantling the loom and trying to work out what they are and getting rid if possible. I was warned off doing that by a Caterham mechanic, so I took his advice

[Frying Pan]

Diagnostics plug is a 16-way connector which woudl normally be under the dash.

 

You say it has a rubber sheath - sounds like the inertia switch, which would normally be on the bulkhead behind battery / ECU / MFU

 

-----See some pictures of the build here. 19,000 miles completed!

[Mankee]

Is it the little white plug covered by a rubber nipple thing near the bottom left corner of this picture?

[SLR No.77]

Not 16 way and not the inertia switch. This one is maybe 4 way, maybe 2 way, difficult to tell because it's female and has 4 slots and 2 smaller holes in the cover piece.

 

I have a picture of it (here) - it's the grey covered section cable tied to the ECU cable - the grey covering appears to be original and I think some of the internal cables are shrouded.

 

Stu.

[SLR No.77]

Mankee - No, I had one of those on my last car and it's not that!

 

Stu.

[Adrian Williams]

Stu

 

Looks like it might be the plug for the exhaust lambda probe, do you have one fitted?

 

 

Adrian

[SLR No.77]

Original Lambda has been swapped for a wideband Lambda / Innovate LC1 ...... I'll retrace the wiring because if it is for the Lambda it may help to incorporate the LC1 into the plug rather than piggy-backing the connections at the ECU!

 

Stu.

[Johnty Lyons]

Stu that's your original lamda connector Now US cos your using an innovate wide band into the Emerald

I suggest you completely remove the engine loom and remove all redundant wires and reloomI know your thinking of putting engine loom back to under the bottom pulley But you can make a good job having it NOT so. Only wires fwd on near side near exhaust are Oil Pressure and Alternator sense and in fact they can come down Off side and across cruciform Mine is like that with no wires anywhere near Headers I just pull wires off sensors and lift engine out leaving all wiring in Engine bay .

 

Old enough to know better Senile enough not to care.

 

[SLR No.77]

Checked it all against the wiring diagram and yes, definately the lambda connection Sigmamark's advice is good .... I'm now think I'll leave it be!

 

Johnty, probably a case of six of one half a dozen of the other etc! There's likely as many connections to make/break when doing an engine out with an o/e engine loom as there are with the old "engine bay loom" setup - my problem is fault finding and because so much of it has been modified in the past, I have found small areas that have proved to be unreliable - I've already been stranded because a wire fell out of the bottom of the inertia switch connector! A lot of hard work was done historically in developing the car (more than I'd ever achieve) but now unfortunately as the years are passing the electrics will really benefit from some fettling to ensure reliability.

 

So far everything that was the original engine loom is stripped out, unwrapped and I'm choosing to route it back onto the engine which is conveniently out of the car on a stand! In doing so I'm checking all the connectors, pins, plugs, sockets, etc and renewing if necessary - I've set myself up with the tools I need so that I can make reliable connections and dispose of any of the small red crimp connectors not normally present in an o/e loom. There's spare pins in the big grey loom plug that will enable extras that have been added to be routed properly within the loom - eg. d/s warning signal, oil temp cable etc., rather than being cable-tied around the engine bay where they were probably most convenient at the time. I'm also using the correct colour coded wire wherever I can - definately OCD!!!!

 

One interesting point I've discovered is that the wiring of the big grey connector varies between different wiring diagrams, and although I've now found a diagram that's pretty close, it still doesn't quite apply!

 

Stu.