moxnix
moxnix Reader
4/20/10 6:18 p.m.

I recently picked up an 88 RX-7 for RallyX and since the ignition switch is dead at this point (was sticking and got ripped out by the prior owner) I figured a push button start would be the way to go. I am not worried about theft of the car I just want to start it up.

How would you normally add this in?
a switch the turn car on (like the on position with the key)? and a button for the starter?

Something I can pickup at advance/autozone?, radio shack?

I do have this diagram from the manual That I am sure that if I could read and understand it I would know most of what I need to know.

Keith
Keith SuperDork
4/20/10 6:49 p.m.

That tells you everything you need. When the key is turned to "ON" (ie, ignition), 12v is sent from the B pin (power from the battery) to ACC, IG1 and IG2. Meanwhile K1 and K2 are also connected.

When you hit the starter button, you'll need to hook ST, L, E, K1 and K2 together. The stock ignition switch disconnects IG2 and ACC at that point, but that's simply to drop the load on the electrical system when you're cranking.

Parts are easy. You need a switch that's rated for enough amperage or you need a relay, and you need a button with the same abilities.

porksboy
porksboy Dork
4/20/10 7:57 p.m.

Keith, what would you expect the amperage draw to be? It is just the starter solenoid and 12 volts to points if it has them.

moxnix
moxnix Reader
4/20/10 8:41 p.m.

Thanks Keith. I knew if I understood it then it would all make sense.

egnorant
egnorant Dork
4/21/10 12:46 a.m.

I did this on my Escort when I wore out the second switch.

I used a headlight switch from a mid 80s Thunderbird as it was a 2 position rocker switch with plenty of heft to handle the loads.

Position 1 (parking lights) was for accessory only while full on was accessory and run. Works like a champ and looks stock enough that a thief would not think to flip it to steal the car.

Found a lighted temporary switch at Radio Shack that was wired to light up and have power only when the switch was at run. Wasn't a very large switch and has held up for 2 years of pizza driving with 20 to 80 starts a day!

Originally I had a direct wire from the button to the solenoid but discovered that this bypassed the clutch switch and I learned that the original solenoid wire was also the ground for my cooling fan relays!

I don't have the function that disables the accessory when starting, but it has not caused any noticable problem.

Bruce

Toyman01
Toyman01 Dork
4/21/10 6:55 a.m.

I did mine with two toggle switches and a button. One toggle for the accessory stuff and one for the ignition. Theft deterrent is not having a working choke. Most idiots couldn't start it cold if they had to.

Raze
Raze HalfDork
4/21/10 7:13 a.m.

we have a main power switch that turns 'on' all accessories and a second arcade button that does the cranking only, works great

mad_machine
mad_machine SuperDork
4/21/10 8:32 a.m.

now this is a starter button I can get behind.

dlmater
dlmater New Reader
4/21/10 8:57 a.m.

I did this on old BMW once. The lock cylinder broke so you could only turn the ingnition on, not energize the starter. More trouble than it was worth to try to replace the cylinder and lock.

I used two relays (one normally open and one normally closed) and a "start" button switch. The switch was a round, 1" lighted pinball machine "start" button I found on e-bay for a few bucks. It came with a panel mount bezel and nut as well. It even had the word "start" printed on the button.

The button/switch was wired to one side of the coil on the normally open relay. The contacts of that relay were wired to the OEM starter circuit on the ignition switch.

The power (12v) for the button light and the contacts in the button/switch came from the normally closed relay. The contacts for this relay got 12v from the OEM ignition circuit. I wired the coil on the normally closed relay to the 12v output wire on the alternator. Thus, once the car started, this relay opened killing power to the button, button light, and subsequent starter circuit.

I mounted the button/switch in the dash in a spare switch panel not used on the dash from the factory. When you put the key in and turned on the ignition, the "start" button on the dash would light. Hit the start button. When the car started, the light on the button went out and the starter could not be re-engaged unless the engine was shut-off. Worked well and it only cost a few bucks for the switch, two relays, and spare wire.

Kia_racer
Kia_racer Reader
4/21/10 9:05 a.m.

Many years ago the run part of the ignition wore out on my 124 Fiat. We pulled the cig lighter and replaced it with a two position round key. Turn the round key and pull it out. then use the normal key to start. Worked like a charm until the engine threw a rod while a friend borrowed it.

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