Now comes the Wiring!

GreatOldOne · #1 18th November 2008, 12:06

As you know, I put the car on it's wheels at the weekend. The fuel lines are complete, and that leaves me with one more job before I can tell if my engine rebuild was successful - wiring her up.

I've not got the original Beemer loom, and neither have I bought the loom from Marlin. What I do have is this:

http://www.nfauto.co.uk/wiring_module.htm

Which I bought at Stoneleigh this year.

Broadly speaking, it should be easy with this - but I'm a little aprehensive about the whole process.

I'm a little unclear on somethings... Such as:

I have two fuel pumps - I assume that each will need it's own relay. There is a fuel relay on the engine harness, and one on the wiring module. Can I the engine one for the HP pump, and the module one for the LP pump?

Cable - I need to several different sizes to accomodate the current draw of different parts of the car, but how much do you think will be required? I don't want to buy 10's of meters of cable when 50cm will do.

I've also been thinking that I could do the whole car in a couple of colours of cable, therefore saving money as I can buy in bigger quantities of each size - but then identify each circuit with these:

http://www.autoelectricsupplies.co.uk/product/344
http://www.autoelectricsupplies.co.uk/product/345
http://www.autoelectricsupplies.co.uk/product/346

Or is that bad form? The majority of it will be wrapped up in loom tape anyway...

Also, what's the minimum wiring required to fire her up?
Pumps,
Ignition circuits,
Oil pressure warning light
ECU

Anything else?

Ta,

Jason

chrislandy · #2 18th November 2008, 12:33

check out
http://www.vehicle-wiring-products.e...e/homepage.php

quick delivery when i bought some stuff from them

MartinClan · #3 18th November 2008, 12:56

Hi Jason

I am a (lapsed) electrical engineer so I should be able to answer some of your questions.

1. I hope you have the loom that came with the engine and ECU. If not you will need to get one.

2. I think that I would run both pumps from the same relay - I did that and it seems fine. In theory you should start the low pressure pump first then the high pressure one a few seconds after. This allows the LP pump to fill the swirl pot before starting the HP pump. But I don't think its really necessary.

3. I would always use colour coded cable. I culled most of mine from the old BMW harness so that the colours AND SIZES match the original. It's easier than working out what sizes you need.

4. Pretty much impossible to guess how much you need cause it depends on the location of the various components. You need to measure I'm afraid and then probably add 25%.

5. Make sure everything is protected with the correct sized fuses! Electrical fires are pretty commom in Kit Cars!

6. Use relays for the large consumption items, headlights, horns etc.

7. Loom tape is OK - but heat shrink is easier!

8. Your list to start her looks about right. I also wired up the alternator as some of the wiring is incorporated in the engine loom.

A couple of other things.

I found the company - Vehicle Wiring Products - to be cheapest.
Get some good tools - cutters, strippers and a decent crimping tool. A soldering iron can also be usefull
Plan your wiring routes carefully!
Use multiway plug and sockets to seperate the loom into three or four chunks. A lot easier to make the loom and easier to fix those little mistakes... Front, Middle (all the stuff in the dash area including the fusebox) and Rear. I also added a sepperate connector for all the dash wiring so that I can unplug the dash and wire it on the bench. One of my next jobs....

Cheers

Robin

GreatOldOne · #4 18th November 2008, 13:33

Quote:

Originally Posted by MartinClan

1. I hope you have the loom that came with the engine and ECU. If not you will need to get one.

Yes, I still have that. It's on the engine and plugged into the ECU

Quote:

Originally Posted by MartinClan

2. I think that I would run both pumps from the same relay - I did that and it seems fine. In theory you should start the low pressure pump first then the high pressure one a few seconds after. This allows the LP pump to fill the swirl pot before starting the HP pump. But I don't think its really necessary.

Did you use a new relay or the one on the engine harness? AFAIK, there's the main and the BMW fuel relay on it.

Quote:

Originally Posted by MartinClan

3. I would always use colour coded cable. I culled most of mine from the old BMW harness so that the colours AND SIZES match the original. It's easier than working out what sizes you need.

As I don't have the original any more, I'll be buying a lot of cable...

Quote:

Originally Posted by MartinClan

5. Make sure everything is protected with the correct sized fuses! Electrical fires are pretty commom in Kit Cars!

6. Use relays for the large consumption items, headlights, horns etc.

The wiring modules have all of those, so I should be OK

MartinClan · #5 18th November 2008, 14:17

Quote:

Originally Posted by GreatOldOne

Did you use a new relay or the one on the engine harness? AFAIK, there's the main and the BMW fuel relay on it.

I used the BMW one which is controlled by the ECU. I haven't added any relays as I also re-used the BMW power distribution box which has everything built in.

Mind you it upset the wife a bit unpicking the BMW loom on the kitchen floor so I couldn't recommend it LOL...

Robin

Simon · #6 19th November 2008, 07:22

Hi Jason,

You've probably already considered this but another alternative is to buy a generic car loom from Premier wiring:
http://www.premierwiring.co.uk/
I think this is what came with my Cabrio (ie could be the loom that Marlin supply) and it was reasonably straight forward to patch the BMW engine loom in to it (and you could still incorporate the CBS fuse/relay panel).

Good luck !

Simon

ps - I've still got parts of the loom from a 5 series if you want it. Its not complete but may be a useful (free) source of wire is you decide to go down that route.

GreatOldOne · #7 20th November 2008, 16:53

Thanks for the offer Simon, but I ordered a whole shed load of wire now. Should arrive tomorrow. Which is nice, considering I have the day off work!

My cockpit warning lights arrived from CBS today - they're the same ones that Pete and Patrick used.

Speaking of CBS, does anyone know if these are SVA compliant?

http://www.cbsonline.co.uk/toggle-sw...ard-3583-p.asp

They look good (ala Beemer Mini) and with toggles in between, quite period & in fitting with the car IMHO

GreatOldOne · #8 25th November 2008, 11:11

Guys - I have a couple of leads coming from the loom that have lost the text on the identifiying tag I put on it when I took the loom out of the donor. Can anyone tell me where they need to go?

They're a thick and slightly thinner red cable (25amp and 17amp?), both terminating in a crimped on ring terminal:

I'm assuming that they need to go to the positive terminal on the battery, but as I can't remember where they went I thought I'd ask to save embarassment later.

peterux · #9 25th November 2008, 21:56

Quote:

Originally Posted by GreatOldOne

Guys - I have a couple of leads coming from the loom that have lost the text on the identifiying tag I put on it when I took the loom out of the donor. Can anyone tell me where they need to go?

They're a thick and slightly thinner red cable (25amp and 17amp?), both terminating in a crimped on ring terminal:

I'm assuming that they need to go to the positive terminal on the battery, but as I can't remember where they went I thought I'd ask to save embarassment later.

I just had a quick look at my car. The larger one is definately the main positive battery feed to the engine loom goes to the positive terminal. I wired mine via a 60 amp fusable link. Not sure about the thinner cable as I cant see this cable on my loom (but mine be either under the dashboard or my loom might be different?).
i'll have a look through my pictures to see if I can see anything similar and dig out my wiring diagrams. Did your donor car have the battery in the boot?

Peter

GreatOldOne · #10 25th November 2008, 22:11

yes, the battery was in the boot on my donor

MartinClan · #11 27th November 2008, 07:24

Quote:

Originally Posted by GreatOldOne

Guys - I have a couple of leads coming from the loom that have lost the text on the identifiying tag I put on it when I took the loom out of the donor. Can anyone tell me where they need to go?

They're a thick and slightly thinner red cable (25amp and 17amp?), both terminating in a crimped on ring terminal:

I'm assuming that they need to go to the positive terminal on the battery, but as I can't remember where they went I thought I'd ask to save embarassment later.

I'll take a look at mine. It's so long ago that I did the wiring I can't remember what it looks like now! My battery was in the boot so I guess it will be the same as yours.

Robin

GreatOldOne · #12 27th November 2008, 11:17

Thanks chaps.

Simon · #13 5th January 2009, 18:32

Well done - it's a great feeling when you get the engine started.

Simon

Patrick · #14 5th January 2009, 21:17

yeahy good 'ol BMW engines mine was the same

GreatOldOne · #15 5th January 2009, 21:28

http://www.greatoldone.co.uk/Site/Bu...ahahah!!!.html

Don't hold you're breath on the video - as said before, no sound, and crap cameraman. You can't really tell the thing is running!

I'll try and get some better video tomorrow. With sound.

limpabit · #16 6th January 2009, 06:18

Well done mate.

Always a great felling when it bursts into life for the first time.

And what a great idea for tagging the wiring.

GreatOldOne · #17 6th January 2009, 18:18

Thanks - I have to confess that it's not my idea - I saw it here:

http://www.lbthosting.com/dutton/others/ReWire.pdf

And like all good ideas, I immediately nicked it.

I've updated the blog page with some better video, which now has 100% extra added sound.

It's also on You-boob as well:

http://uk.youtube.com/watch?v=9qNBE9O_Emw

MartinClan · #18 6th January 2009, 20:28

Awesome. I think you might need a (better) silencer for the SVA though ;-)

I checked out the ETB web site you suggested (for instruments). They are certainly cheaper than Green Gauges and I like the no nonsense advice they give (on the website) as well. Just as well I have been pontificating about ordering from Green Gauges. You may well have saved me some money! (Make the wife happy anyway...)

Robin

Mike · #19 7th January 2009, 12:17

Quote:

Originally Posted by GreatOldOne

Thanks - I have to confess that it's not my idea - I saw it here:

http://www.lbthosting.com/dutton/others/ReWire.pdf

And like all good ideas, I immediately nicked it.

I've updated the blog page with some better video, which now has 100% extra added sound.

It's also on You-boob as well:

http://uk.youtube.com/watch?v=9qNBE9O_Emw

Jason
It is brilliant when you strike an engine up for the first time - well done. I still get a tingle of excitement run down my neck even by other builders videos, and remember gettting an old J2 Comma van engine running in the middle of my Dad's work shop 35 years ago when I was 13 or 14 years old. I used a milk churn for the radiator with pipes dangled loose in to it and a milk bottle for the petrol tank!! Great fun. And well done again for getting it to start first time - no wrong wires, missed earths etc - very impressive.
As Rob says, I think the silencer will need a bit of work??!!

Mike

Patrick · #20 16th January 2009, 08:39

Not seen a DIY one, only the £80 ones

The staged ones look pretty cool that show a build up as you get near the limiter.

I'm going to be putting Megasquirt in mine soon and I'll use one of the outputs as a shift light.