Time to start wiring the car!

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stevieturbo
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Re: Time to start wiring the car!

Post by stevieturbo » Wed Oct 02, 2019 5:59 pm

DaveEFI wrote:
Wed Oct 02, 2019 12:14 pm
Not looked through them all - but one thing stands out. You're using an MS3? That supplies a ground for the fuel pump relay, not a switched 'live'. As do pretty well all of the MS outputs.

I'll have a better look at them on a decent size monitor.

I'd not be able to comment on anything which is race regs specific.
And on top of that, you cannot run the fans directly off the ecu. They must use a suitable relay, and likewise these will be ground triggers to activate.

The photos are a little blurry ( and/or my eyes arent improving lol ), so some parts not so easy to make out. But there are fundamental problems on the above items alone.


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chodjinn
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Re: Time to start wiring the car!

Post by chodjinn » Thu Oct 03, 2019 6:42 am

Hi Dave/Stevie, thanks for the replies and apologies for the shitty pics, i will try to get better ones. Definitely I want to start at the battery and then move forwards, so I've kinda posted pics in the wrong order, sorry.

The rad fans aren't run directly off the ecu, they are triggered by the ecu via a relay (ECU rad out goes to relay, which switches and supplies power to rad fans).

The wiring diagram I used for the fuel pumps I thought was pretty standard relay setup from what I gather (google). I rechecked and it seems ok?

Pin 30 - 12v Fused
Pin 86 - ground
Pin 87 - Power to device (then ground after device)
Pin 85 - Ground to ecu or switch


Ok as for my fuse board (5 relays / 10 fuse generic thing), I use 4 relays off it. The first is the Main Relay, gets power from the 150amp breaker and which powers up two others (Aux for gauges/wideband etc. and the other for injectors and spark). I also take a feed off the main relay for the tacho and ecu (via a fuse). The fourth relay is for the rad fans as described above.

I then use four non-relayed fuses; 1. wipers/washer, 2. brake lights/warning light, 3. interior blower fan, 4. starter circuit

Will get pics later if i can, massive massive thanks for advice (but I have man flu at the moment and feel like poo!)
RIP MGB V8 .... served me well as a learning curve.

R32 Skyline V8 .... this one is gonna be a monster!

DaveEFI
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Re: Time to start wiring the car!

Post by DaveEFI » Thu Oct 03, 2019 9:01 am

When being triggered by MS, the connections to a relay would be:-

+12v Power to 30/51 and 85
Load to 87
Ground trigger from MS to 86

I dunno how happy you are with computers, but a 2D CAD prog like the free version of DraftSight makes drawing so much easier. Once you've drawn a relay (or found a suitable drawing online) you can keep it in a library so never need to draw it again. And you can show the wiring colours you actually use.

Image
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chodjinn
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Re: Time to start wiring the car!

Post by chodjinn » Thu Oct 03, 2019 9:40 am

I've made a wiring diagram in excel (sorry, don't have anything else) - I can't seem to get this into a format that I can upload (I can email). But based on your comments, my fuel relays are wrong...and i think i get it now

For my fuel pumps, I have two relays with built in 30amp fuses. So i feed each of these fuses directly from the battery +ve (via the breakers). These are pin 30
Pin 87 yes, load to fuel pumps

Now I have my 85 and 86 different to what you suggest. I can switch the ECU ground trigger from MS to Pin 86, but how can I add +12v to 85 do I loop it from pin 30?
RIP MGB V8 .... served me well as a learning curve.

R32 Skyline V8 .... this one is gonna be a monster!

DaveEFI
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Re: Time to start wiring the car!

Post by DaveEFI » Thu Oct 03, 2019 12:12 pm

Yup - you can loop the +12v power feed from 30 to 85. Although you might want to use a different +12v supply. Like say one switched by the ignition, with the main power direct from the battery, via a fuse.

It may help the think of a relay as two separate devices. A switch (contacts) and the means to operate it (coil). The coil can be driven by anything you want, without making any difference to what the switch handles.

FWIW, the beauty of using a CAD prog for drawing such things is the files (DXF) are cross platform. The clip I gave was actually done on an ancient Acorn RPC, using ProCAD+, but can be read etc by any other 2D CAD prog.
Dave
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chodjinn
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Re: Time to start wiring the car!

Post by chodjinn » Mon Oct 07, 2019 12:53 pm

Looping is ok, I have done that on another circuit (starter push button). I've updated my wiring diagram to match those comments, will try and upload later this week. Almost finished the decorating now so should be able to get back on the car soon, at long last....

Right, as for ignition etc. I basically don't have an ignition switch/key etc. Everything goes through the FIA kill switch, then the breakers and then the fuse/relay board.

One thing I have guess at is how to wire the starter push button/relay/toggle etc. I based it on what I could find, but I am purely guessing that feeding the relay a +12v 20amp from the fuse board is suitable. You'll understand when you see the diagram. As always, thanks for almost unlimited patience.
RIP MGB V8 .... served me well as a learning curve.

R32 Skyline V8 .... this one is gonna be a monster!

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