Erratic no start/no crank w/ push button start

**S50ti** · 05-05-2018, 04:47 PM

Been dealing with a no start issue on my track car for a while and it’s really getting annoying. Happens totally randomly, no pattern. I got rid of the key/ignition barrel for a master switch and push button for starter. Worked great for a while then slowly and occasionally I’d flip the switch, hit the starter button and nothing. I get accessory/dash/ CEL lights but no crank or click or anything from the starter. Cycle the switch and hit the button a few times... nothing. I can disconnect the battery for 15-20 mins and usually it’ll fire after that. I got to the point of disconnecting he battery between sessions and it would start every time but if I leave the battery disconnected for long periods of time (overnight, weekend) it usually won’t start after that. I’ve even tried tapping on the starter with a hammer & socket extension thinking it may be hung up, nothing. Like I said...very erratic, annoying, frustrating.

Additional info:
-car has ews deleted from ecu
-key is zip-tied through the ignition ring antenna under the dash
-recently replaced the ews antenna module, no change in symptoms (thinking there still may be some level of ign interlock going on)

What am I missing here? Any help or suggestions would be greatly appreciated

**John in Houston** · 05-07-2018, 05:51 PM

In my setup (early car, no EWS), we found voltage drop across the wiring from the OEM harness to the push-button start button. Used a larger gauge wire and soldered it and all issues were resolved. If you used butt-connectors, I'd start looking there.

**S50ti** · 05-10-2018, 10:12 PM

Thanks! I’ve gotten a couple PMs saying to check connectors, grounds... anything I’ve had my hands on. Most likely the culprit. Who wouldve guessed bmw electronics would be so finicky.

**olemiss540** · 05-11-2018, 03:19 PM

Have you tried to apply 12V to the starter directly when it is giving you trouble to see if it starts right up? That would rule out any EWS issues, etc and simplify it to your starter switch wiring or bad switch. Did it do this before you installed the starter button?

**CoMZ302** · 05-14-2018, 02:22 PM

I've had not one, but two of those push button starter buttons fail on me.

They have to take a lot of amps (current enough for the starter solenoid, right?) so they just wear out over time.

https://www.summitracing.com/parts/lng-45466

This one takes 40 amps, which is probably necessary.

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Originally Posted by olemiss540

Have you tried to apply 12V to the starter directly when it is giving you trouble to see if it starts right up? That would rule out any EWS issues, etc and simplify it to your starter switch wiring or bad switch. Did it do this before you installed the starter button?

Yep great suggestion.