How to wire starter button in MX5?

[Synchromesh]

Trying to wire up a starter button for my mk1 MX5, please see picture. Can anyone suggest where the connections should go?


The bottom picture is the original wiring diagram for the ignition switch. The top picture is my new starter button.

Please let me know any other information that you would like me to provide.

Cheers

[Penelope Stopit]

Please post a head-on picture of the switch panel or what symbols are on each switch and warning light

You do know that those switches wont power anything other than a relay dont you?

I or someone will post you instructions later once you have shown the switch and warning light symbols or commented on what you want the switches to do, there are lots of different methods here

The main thing is to ignore any help that doesnt show relays or heavy duty switches in the circuits

You would do better building your own switch and warning light panel. Post what you want to achieve and I or someone else will post you the best method

Edited by Penelope Stopit on Sunday 14th February 10:32

[Penelope Stopit]

That diagram is as follows

B1 and B2 are 2 x battery positive supplies and possibly have heavy fuses

ACC Is for your radio and possibly something else like cigarette lighter, B1 Is Switched to ACC

IG 1 Is the engine ignition supply, it turns on ecu pump etc to make the thing go, B1 Is switched to IG 1 when the ignition is turned on and remains connected when going to the ignition key start position (start button)

IG 2 Is the vehicle ignition systems supply for everything that is only meant to work with ignition on (not the engine...IG 1 does that), B2 is switched to IG 2
Note that IG 2 is disconnected from B2 when turning the ignition key to the start position so that all battery power is available for cranking. Headlights, cooling fan etc should go out on cranking. You may find that the headlights stay on when cranking

[Synchromesh]

Thank you for the response, very helpful!

Would everything not be on a relay anyway? How do I check? Surely the standard ignition switch couldn't flow all the current for everything?

Would it work if I had two switches, one for the stuff thats needed to start the car when cranking and one for everything else that can be switched on when its running?

[PaulKemp]

You may already be aware of this
You can't bypass the ignition key switch totally as it unlocks the steering lock
You have to insert key and turn one click to release that
If we do this on kit cars we simply bypass the second click that starts the car with the push button on the switch plate
As we usually wire our own cars the fuel pump is on 1 toggle and any other stuff can be on the second toggle, most of the time it's the ECU power supply

[Penelope Stopit]

Synchromesh said:

Thank you for the response, very helpful!

Would everything not be on a relay anyway? How do I check? Surely the standard ignition switch couldn't flow all the current for everything?

Would it work if I had two switches, one for the stuff thats needed to start the car when cranking and one for everything else that can be switched on when its running?

The standard ignition switch will be of a much higher current rating than those plastic switches in your panel, you could replace those switches with heavy duty switches that have the same or higher current rating as the ignition switch
Whatever you decide to do, those plastic switches will still need to be replaced with good ones, the plastic switches will fail in a short time due their mechanics not being robust enough. Due to having to replace the plastic switches, you may benefit much by finding switches with a current rating high enough for the job, the problem that you may encounter is that the correct current rated switches are too big for the panel/aperture, if the correct rated switches are too big you would need to use good lower current rated switches and wire them through relays

As the above poster mentioned (which I took for granted) Dont forget to remove the steering lock, your car will not be legal with the steering lock fitted once you are able to start the car without keys, also check with your insurance company about the theft side of your policy if this modification is carried out

So, its good switches with relays or even better switches wired direct but switch size may well play a part in your choice