Engine Push Start Button Install

[AndrewBird]

why the need for the relay?

Um, which one?

If you mean the one he used in the original post, it's because the pushbutton can't handle the amp draw the starter motor makes.

[e304me]

well it goes to another relay anyways right? i have a modified cig lighter as my starter button and it seems to do the job

[DaveSmed]

well it goes to another relay anyways right?

No.

Interesting the cig lighter passes enough current to engage the starter solenoid. Kinda thought it might, BUT for the best reliability, you will want to add in a relay yourself. There is a chance the solenoid may need more amperage one day (maybe on a hot engine on a hot day? who knows) and the cig lighter is just going to heat the element up instead of actuate the starter.

[Sean]

well it goes to another relay anyways right? i have a modified cig lighter as my starter button and it seems to do the job

Yea, I saw that video. I'd be worried that you'd melt your ashtray apart like that. The starter draws a lotttttaaa power.

[e304me]

Its actaully just the solenoid it powers. And i welded a bead across mine so it wont heat up

[Axxe]

The starter solenoid acts as the high current relay. An extra relay on the pushbutton doesn't hurt though, especially since most are cheap and can't handle more than a few amps.

[AL GReeNeRy]

fyi, my cig lighter starter mod is pretty much the same as this except mine was free!! used a relay as well and instead of buying another switch, i used my broken cig lighter that doesnt stay down. so there will be no melting of any part of my car!

[DaveSmed]

Its actaully just the solenoid it powers. And i welded a bead across mine so it wont heat up

Damn, that works too. Good thinking.

[AndrewBird]

Anyone got a link to this video you speak of?

[evil_twin]

I'm not sure if this was asked already, but can you still crank the car without pushing the button?

[e304me]

you could wire it that way but if you cut the wire you need to tap into then no

[Doughnut]

I'm not sure if this was asked already, but can you still crank the car without pushing the button?

If you wire the button same as the OP, then Yes, you can still use the key to crank the car over.

[MA-BMW]

Sooooooo, anything happen with the key pad and what not?

[Bread]

Sooooooo, anything happen with the key pad and what not?

I don't understand the point of the key pad when you can program a security code into the OBC to disable the starter anyways.

As for making your wire connections, always use solder. If your soldered joints are cracking, then you didn't do it properly. A cold solder is brittle because it sticks to the surface of the wire, rather than penetrating the strands. Cold soldering is caused by heating the solder directly onto the soldering iron and dripping it onto the wire. Good, clean wiring with the solder drawn through the strands (heat the wire, not the solder) will be stronger and conduct better than any crimp connector. Especially those cheap wire taps. Soldering your wire taps also protects the connections from corrosion. This is especially important for wiring done under the hood.

I've got a truck with many aftermarket wiring connections made with wire crimps over 30 years ago. To this day I'm battling the many unreliable connections from years of moisture entering the contacts causing surface corrosion between the wires. Had these connections been properly soldered and wrapped, I wouldn't be dealing with this. Hell, I found a handful of pastic wire taps under the dash of my M3 that were no more than 10 years old and they were already totally crap.

Plastic wire taps are the lazy way of doing electrical work. I remove them everytime I come accross one. They'll only cause you more headache in the future.

[DaveSmed]

I don't understand the point of the key pad when you can program a security code into the OBC to disable the starter anyways.

As for making your wire connections, always use solder. If your soldered joints are cracking, then you didn't do it properly. A cold solder is brittle because it sticks to the surface of the wire, rather than penetrating the strands. Cold soldering is caused by heating the solder directly onto the soldering iron and dripping it onto the wire. Good, clean wiring with the solder drawn through the strands (heat the wire, not the solder) will be stronger and conduct better than any crimp connector. Especially those cheap wire taps. Soldering your wire taps also protects the connections from corrosion. This is especially important for wiring done under the hood.

I've got a truck with many aftermarket wiring connections made with wire crimps over 30 years ago. To this day I'm battling the many unreliable connections from years of moisture entering the contacts causing surface corrosion between the wires. Had these connections been properly soldered and wrapped, I wouldn't be dealing with this. Hell, I found a handful of pastic wire taps under the dash of my M3 that were no more than 10 years old and they were already totally crap.

Plastic wire taps are the lazy way of doing electrical work. I remove them everytime I come accross one. They'll only cause you more headache in the future.

Hmm, well, thats not entirely true believe it or not. I agree that all scotch locs should be deposited in the nearest trash can, word is these days is best connection comes from a proper mechanical crimp+silicone or adhesive lined heatshrink.