Time to start wiring the car!

General Chat About Electrics, And Ignition Systems.

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DaveEFI
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Post by DaveEFI »

Sorry not to have been any help, but I know zilch about race car wiring to regs. So best not to muddy the waters. :D


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chodjinn
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Post by chodjinn »

DaveEFI wrote:Sorry not to have been any help, but I know zilch about race car wiring to regs. So best not to muddy the waters. :D
Haha don't worry about it I'm in a similar position. I'm finding as I go along, as usual, there are about 15 other jobs I forgot about first!
RIP MGB V8 .... served me well as a learning curve.

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

chodjinn
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Post by chodjinn »

So I have been at this for weeks, and particularly most of this weekend, and despite some great help from Richard I am still no closer to making a wiring diagram or getting my car wired. I am massively stressed about this and on the verge of abandoning it all to recoup some money. I have wired in the MS3 Pro mostly, to the engine sensors/injectors/cops. The main circuit is still a mystery to me. Different people tell me different things, and always it's wrong after I make changes.

Rich sent me a wiring diagram, but it has two separate fuse boards on it and I don't want that.

I don't get why I can't just have the fia kill switch and ignition toggle switch turn everything on via the fuse/relay board, and a push-button starter for the starter solenoid? I want it as simple as electrically possible!
RIP MGB V8 .... served me well as a learning curve.

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

stevieturbo
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Post by stevieturbo »

Ultimately you can do whatever you want.

What 2 fuse boards has he ? Some for permanent lives and others ignition only or something ?

As long as the push button can handle the current of the solenoid ok, I dont see an issue with a push button for starting ?

Simple is good !
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unstable load
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Post by unstable load »

Why not have a look at what the scrutineers check and wire according to that? You have come too far to abandon this project over this problem.

Check what they want to see and make it as basic as possible to meet the requirements.
Cheers,
John

chodjinn
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Post by chodjinn »

stevieturbo wrote:Ultimately you can do whatever you want.

What 2 fuse boards has he ? Some for permanent lives and others ignition only or something ?

As long as the push button can handle the current of the solenoid ok, I dont see an issue with a push button for starting ?

Simple is good !
Basically yes, but I don't know how to quite set it up like that. He sent me an email late yesterday which kind of explains the ignition on/permanent - but in my head turning the kill switch makes everything 'permanent' surely as that is controlling the main feed to the fuse board... I left it all along last night for a break for a day or so will get back on it later today now I have calmed down a bit hah. I have another mate who does wiring looms for a living reviewed my slightly older diagram, basically said I was almost there (but then I messed it up again!)

The push button is a proper one not some cheapo Chinese junk (I hope!).
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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Post by DaveEFI »

Just for info on the MS side. You do need to stick reasonably close to what they suggest. The reason being that MS switches pretty well everything on the ground side, and can sometimes provide that ground to some things when MS is powered down. So everything associated with it has to powered down at the same time as it.

(An example of what I mean could be the coils. If they had power and MS grounded them when powered down, they could burn out. Not saying this happens - just an example)
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chodjinn
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Post by chodjinn »

I should be ok for the MS for now, following the instructions to the letter.

I think my main issue was understanding 12v ignition and 12v permanent, I couldn't get my head round it. I have a little better knowledge now so after a few days off I am now trying to redraw my diagram, for like the 8th time...
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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Post by DaveEFI »

I'd call them constant and switched feeds. Ignition switched would be things that only work with the ignition switch on. Sidelights and so on work at any time.
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stevieturbo
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Post by stevieturbo »

If it's a race car, then really there isnt much that would need a permanent supply.

but it might be nice to have things like internal power, some sort of lighting etc available when the key is off so to speak.

By internal power, I mean maybe a radio, power outlets for cameras, chargers, some lights inside etc.
It can be handy to have the cooling fan able to operate when the key is off too, although this would be via a manual switch as the ecu would not be in control at that point.
Only caveat there is battery power and dont run it flat. But I always favour huge batteries, none of that race crap !

Pretty much anything else would always be a key on scenario anyway. As for numbers of fuses, as said before lots of fuses cant be a bad thing. It can make some wiring easier, and fault finding even easier....also makes less chance of one circuit dropping out causing more of a problem if it does.
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chodjinn
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Post by chodjinn »

Ok so basically what I am doing at the moment is pretty similar to what Stevie says.

Battery > FIA Kill Switch > 300amp breaker -> this line then splits to;
> starter > inline 70amp fuse > 65A alternator
> 150amp breaker > fuse/relay board

The first relay will be the main/efi relay, which I am going to use to switch on the other four (which cover fuel pumps, injectors/COPs, Aux (gauges/lambda) and radiator fan).

The fuel pump and rad fan will be switch on by the MS3 ECU signal.

From the same fuse board I have 12v fused feeds for things like the wiper switch, washer button, interior fan/demist circuits. These are all individual direct off the main fuse board, so I guess would be '12v perm', however the relays will be switched by the ignition toggle switch, so I guess they would be '12v ignition', but essentially everything is 'ignition on'.

That's as far as I have got so far. It's looking like I might not use the No.2 connection on the FIA kills switch as I won't be needing it. I know I need a few more fuses for the starter/alt circuit but am learning, slowly. Baby steps, because that's clearly what I was not doing previously and caused me problems lol!
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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Post by DaveEFI »

You don't need an extra relay for the 12v feed to the injectors. Just power them from the same one as MS, assuming the standard 30 amp auto type. Nor do you need to power things like the gauges and so on via a separate relay, as they are all low(ish) power. The fan would be best on a separate circuit fed direct from the battery (which could also power other none noise critical stuff like lights etc), via a relay, as would the high power circuit to the ignition. Both to keep electrical noise away from MS.
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chodjinn
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Post by chodjinn »

DaveEFI wrote:You don't need an extra relay for the 12v feed to the injectors. Just power them from the same one as MS, assuming the standard 30 amp auto type. Nor do you need to power things like the gauges and so on via a separate relay, as they are all low(ish) power. The fan would be best on a separate circuit fed direct from the battery (which could also power other none noise critical stuff like lights etc), via a relay, as would the high power circuit to the ignition. Both to keep electrical noise away from MS.
You see why I get confused and frustrated with it all? One person says one way, then one person says another.

The relays are going as per my reply above because that is how the guy who is selling me the fuse/relay board has advised me to do it, otherwise I am back to square one yet again. I have been at this since May and not actually started wiring the car yet!
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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Post by DaveEFI »

For the MegaSquirt part, follow the MegaSquirt external wiring diagram for your particular one.

I'd ask your guy just why he thinks a separate relay is needed for injector power. It's not needed and simply adds complexity.
Dave
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chodjinn
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Post by chodjinn »

DaveEFI wrote:For the MegaSquirt part, follow the MegaSquirt external wiring diagram for your particular one.

I'd ask your guy just why he thinks a separate relay is needed for injector power. It's not needed and simply adds complexity.
The relay is for both injectors and cops. I am wiring in an isolation switch so they can be turned off when faffing around with the MS3. Same for the fuel pump relay as well.

It's looking increasingly like I am never going to be able to race this car. The exhaust needs redoing all the way through the cabin to comply with the half-wheelbase rule for exhaust exit (I have no room to route it under the car so it would have to go through the cabin). And to do that I will have to cut out the tubbed front arches for clearance in the engine bay (which, coincidently would make it time attack legal). That is far too much work I think, and after 4yrs of working on this I don't have it in me to start chopping a freshly restored and painted shell up.

So looks like this will be a track toy only now. Doesn't affect the wiring I suppose, certainly does affect my motivation after spending £25k+.
RIP MGB V8 .... served me well as a learning curve.

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

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