Troubleshoot a No Start...then Start

[mziggy16]

Some maybe relevant stats:
07 Z4M, 130k miles
Battery/alternator last replaced 2014 around 80k.
Original starter.

Daily driven for the last 3 months, no issues.

Came home from work tonight, parked it and it sat for an hour. Hopped in, turned the key, lights came on, heard a click and then nothing - no crank, just silence. Repeated this maybe 3 times and was running late, so I pulled out the key and took my wife's car.

Came home tonight (3 hours later) and went to troubleshoot it and it fired right up. Twice. No issues.

Thoughts?

[3002 tii]

check battery cable?

[mziggy16]

Originally Posted by 3002 tii

check battery cable?

All snug.

[Finnegan]

Clutch depression sensor switch? I had my clutch stop extended a bit high at one point and had this intermittent issue. Could be a bad switch, or there's an aftermarket clutch stop that's become misadjusted. From there it's on to the ignition switch. There are a few threads covering that issue in higher mileage cars.

Here's a pretty good one. Z4M Intermittent Start Issue https://www.zpost.com/forums/showthread.php?t=791803

[Daemonblitz]

Most likely a starter. Mine is also on its way out. Got stuck at the gas station after filling up once already. We share the same starter as the E46 M3 and it's not uncommon to have it fail.

[Reborn_]

sounds like the starter (they can get intermittent like that). But I would take the route Finnegan suggests, as those are cheap and easy to check off the list before going to the starter. I also had this experience and my root cause was the clutch engagement switch (the clutch stop was set a hair too high).

[Steeler]

Clutch Stop. Can be temperature dependant.

[mziggy16]

Helpful stuff - thank you.

Can someone point me in the right direction on troubleshooting the clutch stop/depression switch option? The clutch has not been modified in any way.

I'll probably also go ahead and replace the ignition switch after I troubleshoot the clutch stop.

Thanks again.

[ceeyo]

It may be your ground cable (engine to chassis)

07 mcoupe 151k miles DD (60 miles a day)

Long story so bear with me lol

Same thing happened to me a year ago. Fired back up an hour later and never happened again. Replaced the battery to be safe (it was oem anyways)

This last Feb, my intermittent start was happening almost every other day (shake car or push start to get it to fire up)

Ruled out ignition switch since all dash lights came on.

Ruled out clutch switch since cruise control was fully functional.

Cleaned battery terminals but it wasn't dirty to begin with.

I read about all the posts regarding the starter and how it sometimes fails to start due to either age or brushes randomly unable to make contact but whenever the car would fire up, the starter was strong so I had my doubts about that being the culprit.

I reluctantly replaced that starter and two days later, no start again until I push started it.

One morning otw to work I went over a large puddle when it was raining hard in LA. Otw back from work, radio kept restarting and a bunch of dash lights came on and car stalled (signs of a dying alternator) but fired up immediately and I was able to get it home where it wouldn't start shortly after. Did not try and use for a few days since I was pretty over it.

I figured the starter and alternator issue had to be related and remembered reading about how the engine, starter and alternator are all connected and use a single ground cable to connect back to chassis (someone correct me if I'm wrong) so I grab jumper cables and attached the neg end to the engine hook and the other neg end to neg terminal under the hood and the car fired right up.

I didn't bother looking at the ground cable and just made a new one from the engine to the negative terminal.

TL DR

your ground cable is probably corroded / going bad

[Steeler]

Originally Posted by mziggy16

Helpful stuff - thank you.

Can someone point me in the right direction on troubleshooting the clutch stop/depression switch option? The clutch has not been modified in any way.

I'll probably also go ahead and replace the ignition switch after I troubleshoot the clutch stop.

Thanks again.

Ziggy,

Look behind the clutch pedal arm and you will see a disc on the firewall.
Turn that disc clockwise to thread it in. Thread it in all the way and try starting the car.
If car no start then you can eliminate the clutch stop scenario. Could still be the switch tho.

Hope it helps

[mziggy16]

Originally Posted by dbarton62

Ziggy,

Look behind the clutch pedal arm and you will see a disc on the firewall.
Turn that disc clockwise to thread it in. Thread it in all the way and try starting the car.
If car no start then you can eliminate the clutch stop scenario. Could still be the switch tho.

Hope it helps

Will do. Sounds like a few places to start tonight to narrow this down.

Thanks to all for the replies - all very helpful. I'll report back once I learn more.

[XMetal]

If the clutch stop haven't been modified, then it's most likely not the clutch depression sensor switch. You can also test out the clutch depression sensor switch by turning on the ignition, but don't start the car. Then press the clutch and you should hear the relay click. If you hear the relay clicking, then your clutch depression sensor switch is most likely OK.

The ignition switch is the most likely culprit as Finnigan suggested. It can cause intermittent starting issues. Just replaced the ignition switch on my 15 year old (143K miles) X5 and it solved my intermittent starting issue on that car. It shares the same switch as our Z4.

[mziggy16]

It appears to have something to do with heat.

Drove the car home from work, shut it down and then tried to turn it over...and nothing.

I heard the click of the clutch depression sensor when the ignition was on and I depressed the clutch, so at least that can be ruled out.

[Reborn_]

Originally Posted by mziggy16

It appears to have something to do with heat.

Drove the car home from work, shut it down and then tried to turn it over...and nothing.

I heard the click of the clutch depression sensor when the ignition was on and I depressed the clutch, so at least that can be ruled out.

I'll share my story.

I bought my car in Portland (colder than so-cal) and drove it down. About 2 weeks later, I started having this issue. It ended up being that I had to adjust the clutch stop slightly lower so that the switch would engage every time. It did seem as if that slight increase in temperature made the difference. Since I adjusted it down, I have not had the issue.

W.R.T. the clicking of the relay, before I moved the stop, every time I tested the clutch, it would click. I just never listened for it on an attempt where I got a no start (which it sounds like you did). I would still adjust the stop a few turns down and try again, just to be sure. Takes 30 seconds.

[mziggy16]

Just went back out...turned the key and no start.

Then, turned it a second time and it started.

I also went ahead and adjusted the clutch stop, so that's crossed off the list.

More troubleshooting later this evening.

[XMetal]

Originally Posted by mziggy16

Just went back out...turned the key and no start.

Then, turned it a second time and it started.

I also went ahead and adjusted the clutch stop, so that's crossed off the list.

More troubleshooting later this evening.

How did you adjust a stock clutch stop? As far as I know, the stock clutch stop is already at the floor of firewall and isn't "adjustable". Even if the stock clutch stop backed out to the point of falling off, it still should not be high enough for the sensor not to trigger.

[mziggy16]

Originally Posted by XMetal

How did you adjust a stock clutch stop? As far as I know, the stock clutch stop is already at the floor of firewall and isn't "adjustable". Even if the stock clutch stop backed out to the point of falling off, it still should not be high enough for the sensor not to trigger.

I don't think it moved at all, but I turned both the disc and the phillips head in the middle of the disc clockwise to try and get it a touch tighter.

From what I was hearing, assuming I was hearing the sensor, was the dull click sound of the sensor maybe a half or so inch from hitting the clutch stop.

[mziggy16]

Originally Posted by ceeyo

It may be your ground cable (engine to chassis)

07 mcoupe 151k miles DD (60 miles a day)

Long story so bear with me lol

Same thing happened to me a year ago. Fired back up an hour later and never happened again. Replaced the battery to be safe (it was oem anyways)

This last Feb, my intermittent start was happening almost every other day (shake car or push start to get it to fire up)

Ruled out ignition switch since all dash lights came on.

Ruled out clutch switch since cruise control was fully functional.

Cleaned battery terminals but it wasn't dirty to begin with.

I read about all the posts regarding the starter and how it sometimes fails to start due to either age or brushes randomly unable to make contact but whenever the car would fire up, the starter was strong so I had my doubts about that being the culprit.

I reluctantly replaced that starter and two days later, no start again until I push started it.

One morning otw to work I went over a large puddle when it was raining hard in LA. Otw back from work, radio kept restarting and a bunch of dash lights came on and car stalled (signs of a dying alternator) but fired up immediately and I was able to get it home where it wouldn't start shortly after. Did not try and use for a few days since I was pretty over it.

I figured the starter and alternator issue had to be related and remembered reading about how the engine, starter and alternator are all connected and use a single ground cable to connect back to chassis (someone correct me if I'm wrong) so I grab jumper cables and attached the neg end to the engine hook and the other neg end to neg terminal under the hood and the car fired right up.

I didn't bother looking at the ground cable and just made a new one from the engine to the negative terminal.

TL DR

your ground cable is probably corroded / going bad

Where is the engine to chassis ground? Is this like the e90 near the header exit/attached to a heat shield under the car? Not finding anything in searches.

[chickdr]

My money is on the starter. I have heard it is a common issue and presents just the way you describe it. Easy DIY and not too $$$ either.

[mziggy16]

Replaced the ignition switch a few days ago. Drove it two nights in a row, got it up to temp and then came home, shut it off and it fired back up multiple times.

However, last night, on the second re-fire it cranked weakly and then stopped. Then I turned it off and fired it back up again.

So...maybe problem solved? Time will tell, I suppose.

[Finnegan]

Originally Posted by mziggy16

Replaced the ignition switch a few days ago. Drove it two nights in a row, got it up to temp and then came home, shut it off and it fired back up multiple times.

However, last night, on the second re-fire it cranked weakly and then stopped. Then I turned it off and fired it back up again.

So...maybe problem solved? Time will tell, I suppose.

Quite a mystery. It is unlikely, but possible, that there are multiple causes. It might be an ignition switch and the starter for example.



The weak crank, then good crank intermittent issue rules out the battery and alternator for me. I'm wondering if there's also a bad/weak connection at the starter, or the ground as ceeyo suggested.

Hmm...

[mziggy16]

Originally Posted by Finnegan

Quite a mystery. It is unlikely, but possible, that there are multiple causes. It might be an ignition switch and the starter for example.



The weak crank, then good crank intermittent issue rules out the battery and alternator for me. I'm wondering if there's also a bad/weak connection at the starter, or the ground as ceeyo suggested.

Hmm...

Where is the engine to chassis ground?

I'm going to keep driving it to see if it keeps acting up to, hopefully, isolate more variables (if there are any). At least the ignition switch and clutch stop are ruled out.