Problem: Ignition——-Solution: Push Button Start

[cbecker47]

One day I decided to drive my e28 to work and when I was trying to go to lunch, I go to start my car and all I got was a click. All light on battery is good, so I tried to hit the start with a large wrench to maybe break it loose and nothing. So, I had someone help me push and I popped the clutch and got her started. I recently got the alternator changed so I know it couldn’t be that. Looks like my starter needed to be changed. I picked up one at a local autozone it was $100 and $40 for a core fee. And after about two hours I got the old one out and new one in. Hop in the driver seat turn the key and nothing yet again. Tried it a few times, giggled the key. Then it randomly started back up. Now came to the conclusion it was my ignition switch needed to be swapped out. I just dropped tons of money into my car on paint, alternator, starter, and now I need a $130 Switch. I did some research and decided to hook up a push button start.

This is the link to the eBay product I bought it was $12

https://m.ebay.com/itm/Universal-12V-Ca ... SwSzRZTtdJ

So, I took off the steering column exposed the ignition wiring.

The relay for the push button start has four wires:

Red Constant 12v+
Black Ground/earth
Two blue wires: One to Accessory and the other to start. Some also do ignition and start.

Then I popped out my cigarette lighter and mounted the push button in that position.

You still need to have your key turned into the last position and then press the button to start the car.

I will post pictures soon.

Constant 12V+ Red Ignition Switch Harness
Starter Black Ignition Switch Harness
Ignition Green Ignition Switch Harness
Accessory. Purple Ignition Switch Harness
Tach Black Coil
Brake Switch Green/Red Brake Switch
Parking Lights Gray/Black L Gray/White R at Light Switch
Hood Pin n/a
Factory Disarm n/a
Door Trigger Brown/Purple (-) Passenger's Pin Switch
Door Lock Yellow/Blue (-) Driver's Kick Panel
Door Unlock Green/Blue (-)
Horn Wire Brown/Yellow (-) Steering Column

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[tig]

Are you sure it's the switch itself? Did you test it? Or could it have been the lock cylinder?

I'm sure you can find a used switch and harness (comes as one piece cheaply).

[davintosh]

The switches do go bad, and can be had for less than $130; ECS Tuning has one for $86.50, and BMW of Rochester has it for $81.22. Not cheap, to be sure, but much better than $130, and better in the long run than the push button starter.

The switch in my 528e went bad several years ago, and I rocked the push-button switch for a while, but tired of it and just replaced the switch. I think it was about $65 at the time. Replacing it was, um, interesting, but very doable. The space it fits into is pretty tight, and getting it lined up was tricky.

Part number is 61321376322.

[a]

My son had a key ring with a pound of keys and 247 blade Swiss Army knife. It wore out the switch so starting was iffy. I had a push button. Spliced it into the yellow black wire and a hot IIRC. Viola, another cheap fix for the Grape

[tn535i]

My dad has the opposite problem on his old Honda. It will crank and run but if you let the key return all the way to run position the car dies. So he added a switch to make that connection but now the car will keep running even if you take the key out, until you kill that switch.

Ignition switches much harder to find for an old Honda Prelude.

[Mike W.]

Are you sure it's the switch itself? Did you test it? Or could it have been the lock cylinder?

I'm sure you can find a used switch and harness (comes as one piece cheaply).

Not really. Since they went to the plastic housing in the early 80s the housing is always cracked. It might work in place, but I wouldn't install a cracked used one.

[cbecker47]

Are you sure it's the switch itself? Did you test it? Or could it have been the lock cylinder?

I'm sure you can find a used switch and harness (comes as one piece cheaply).

I didn't take the switch itself out to test it, from my understanding it goes lock cylinder to ignition switch and harness. I checked a local autozone prices and figured all just go this route.

[cbecker47]

The switches do go bad, and can be had for less than $130; ECS Tuning has one for $86.50, and BMW of Rochester has it for $81.22. Not cheap, to be sure, but much better than $130, and better in the long run than the push button starter.

The switch in my 528e went bad several years ago, and I rocked the push-button switch for a while, but tired of it and just replaced the switch. I think it was about $65 at the time. Replacing it was, um, interesting, but very doable. The space it fits into is pretty tight, and getting it lined up was tricky.

Part number is 61321376322.

Thanks for the references davintosh, I most likely will be ordering from one of those sources in the future. It definitely looked a bit challenging to take off the switch.

[demetk]

Does this unit have a safety anti-grind feature to prevent activating the starter when the engine is running?

[cbecker47]

Does this unit have a safety anti-grind feature to prevent activating the starter when the engine is running?

It doesn't but I was thinking if I were to put a switch in between one of the wires to create like an on/off switch would that work?

[demetk]

You could create a automatic safety switch with a 5 pin relay that has a normally closed contact (pin 87a) and use the alternator blue wire as the trigger for the relay. When the engine is off the push button switch will work normally but when the engine starts the relay will click on and disable voltage to the push button switch. Let me know if you need help with drawing the curcuit up.

[cbecker47]

You could create a automatic safety switch with a 5 pin relay that has a normally closed contact (pin 87a) and use the alternator blue wire as the trigger for the relay. When the engine is off the push button switch will work normally but when the engine starts the relay will click on and disable voltage to the push button switch. Let me know if you need help with drawing the curcuit up.

Demetk if you can draw that circuit up for me would be highly appreciated.

And without having to start a new thread to ask this question, does anyone know the size of the upper radiator hose on an e28 with a m30? I need to install an after market temp gauge because my cluster doesn’t report temp amongst other things.

[davintosh]

You could create a automatic safety switch with a 5 pin relay that has a normally closed contact (pin 87a) and use the alternator blue wire as the trigger for the relay. When the engine is off the push button switch will work normally but when the engine starts the relay will click on and disable voltage to the push button switch. Let me know if you need help with drawing the curcuit up.

Demetk if you can draw that circuit up for me would be highly appreciated.

And without having to start a new thread to ask this question, does anyone know the size of the upper radiator hose on an e28 with a m30? I need to install an after market temp gauge because my cluster doesn’t report temp amongst other things.

There is hope for your non-op temp gauge. Might actually be less work than a kludge workaround.
http://www.mye28.com/viewtopic.php?t=34049

[demetk]

Demetk if you can draw that circuit up for me would be highly appreciated.

This might work. It depends how fast the alternator begins to charge. I don't think it will provide voltage on the blue wire until the engine is running.

[Mike W.]

Demetk if you can draw that circuit up for me would be highly appreciated.

This might work. It depends how fast the alternator begins to charge. I don't think it will provide voltage on the blue wire until the engine is running.

Hmmm, I like the way you think, outside the box. My first thought was it wouldn't work, that the blue wire coming from the cluster would energize the relay, but the resistance is probably too high on the bulb to pull in the relay. Next I was thinking the bulb would glow, but probably not since I think voltage is being supplied to the D+ terminal. But now I'm thinking it might be enough that there wouldn't be enough voltage/current to initiate charging, I have seen that before on other cars where charging wouldn't start because bulb resistance was too high and there wasn't enough excitation current. But I think that was on an electromechanical regulator, not an electronic one, so that might not apply. So I guess I'll have to say, I dunno!

Good creative thinking though.

[demetk]

Well I use the blue wire to trigger my fog light relay on when the engine starts so I think it will work.

[Mike W.]

Well I use the blue wire to trigger my fog light relay on when the engine starts so I think it will work.

Really? But they only come on with the car running, not with the ignition switch on? Hmmm, interesting, what can I use that for?

[foamy]

yes i too have installed the push button start due to a failing switch. most of the time it still works from the key but every so often it just wont crank the engine and i have to push the button.