Troubleshooting a no-crank issue

[E46m3zcp]

Hello,

My car clicks repeatedly (as in: it's not a single "click", then nothing, but a rapid click-click-click) as if there wasn't enough power to spin the starter. I'm at that point where I'm considering diving into the engine bay and removing parts to get to the starter motor, but I reeeealy would love to avoid having to do that.

What I've done (note I have 2 m3, so it's easy for me to swap parts):

- Battery charger in "jump start mode" -> still just clicks
- Jump start with another car -> still clicks
- Swap batteries with the other m3 -> still clicks
- test both batteries, both tested above the spec (in cranking amps), and around 12.6V
- Checked the grounds and wires I know of: the + connection by the drug-bin, the ground connection on the side of the cylinder head (above the headers), and the engine to chassis ground strap by the passenger-side engine mount. Looked perfect, but still sanded both ends connectors just in case. -> still clicks
- Noting that the negative battery wire looked a bit damaged - probably from connecting and disconnecting while in storage (really not that much, like 2 copper strings inside the large wire are cut, and the clamp has slipped off the rubber), swapped wires with the other M3 -> still clicks
- I read the codes and there aren't any relevant codes (like EWS)

I also did things like shorting the chassis to engine from above with jumper cables, but I don't trust these jumper cables.

The car is relatively clean there is below-average corrosion on things like connectors, nuts and bolts, etc. I'd be surprised if anything corrosion-related would be an issue.

So before removing the intake, did I miss something? Are there any common failure modes that correspond to these symptoms and aren't ruled-out by my tests?

I'm not really sure what to do once I have access to the starter... hit it with a rubber mallet?

Thanks for any advice.

[sapote]

Measure the voltage from starter to engine while key turned to Start position (it’s easier to measure from alternator big red cable to alternator body). If it’s above 10v then it’s a bad starter.

[Bebop]

Remove the starter and test it outside the car.
Check if the engine isn't seized and spins.

[E46m3zcp]

sapote I'm measuring a 0V between the alternator body and red cable, when attempting to start the engine (whether the key is turned to start or not doesn't change the 0V voltage). The clicking I hear is a click sound that sounds like a relay, maybe not the starter engaging into the flywheel (I think this would be a louder click).

I made sure that the point I was taking the ground on the alternator was connected to the negative battery terminal by checking that there is a near 0-ohm resistance between the negative terminal in the "drug-bin" and the spot on the alternator case I was using.

Also the measurement is not a straight 0, it is more like 0.002V, as I think is typical of an open circuit (I suspect the starter isn't getting powered at all).

Could it be a bad solenoid? Could it be an issue with the EWS or DME? Would it still "click" in this case?

Bebop I had this issue intermittently happening before it started being all the time, I think this rules out a sized engine (engine doesn't seize intermittently, if that makes sense). Also I see no reasons the engine would seize spontaneously, although who knows...
I will get to the starter when I rule out other possiblilities. I'm trying to see if I can figure this out without removing the intake manifold.

[Slideways]

sapote I'm measuring a 0V between the alternator body and red cable, when cranking. The clicking I hear is a click sound that sounds like a relay, maybe not the starter engaging into the flywheel (I think this would be a louder click).

Bebop I had this issue intermittently happening before it started being all the time, I think this rules out a sized engine (engine doesn't seize intermittently, if that makes sense). Also I see no reasons the engine would seize spontaneously, although who knows...
I will get to the starter when I rule out other possiblilities. I'm trying to see if I can figure this out without removing the intake manifold.

Removing the intake takes 15-20min max if you have done it before. Out of all BMW engines, the S54 probably has one of the easiest intake manifolds to remove.

[E46m3zcp]

Okay, if someone could confirm this it would be great but after some research: It's abnormal to have 0V between the red cable on the alternator and the alternator case. It means that the circuit between the drug bin positive post and the alternator/starter positive is open. This does not point to a bad solenoid or starter, but to a wiring issue between the + near the drug bin, and the starter +.

[Bebop]

You should def have 12V on the main charging wire that's for sure.

[E46m3zcp]

I feel dumb. My measurement was bad as I was probing on the bolt where the red cable goes into the alternator, but this bolt head is insulated. For anyone looking at this and struggling to measure the voltage on the alternator's B+, don't measure on the bolt by the B+ terminal, it's insulated! Instead put your multimeter + probe through the plastic shield on the back of the alternator to get to a valid B+ point.

Okay, so I did the test again and the voltage seems to never drop below 10V (my readings oscilated between 10.5V and around 12V while the key was being turned in position 3. So based on sapote's answer it looks like I got a bad starter.

[sapote]

Okay, so I did the test again and the voltage seems to never drop below 10V (my readings oscilated between 10.5V and around 12V while the key was being turned in position 3. So based on sapote's answer it looks like I got a bad starter.

Sounds like a bad starter as it should spin with 10.5v

It's a plastic cap nut for safety when working around the area.

[E46m3zcp]

TL;DR still not working, I made some progress but I am struggling with the EWS and SMG preventing any further testing.
My question here is what does that P, N thing mean (see below, in bold), and is there a way to crank an SMG car without putting back pentosin and the airbox every time I need to attempt?

Progress made so far (bear with me, I'm inexperienced but determined!) :

• Removed air intake, cleaned up 3 starter connections at the solenoid.
• Removed salmon relay to avoid getting air in the SMG pump when I reconnect the battery.
• Removed fuel pump fuse as I don't want the car to start without an intake manifold.
• Reconnected battery and put the key to "start".

Note the car was left in N, to avoid having to use the SMG system to get the car in neutral for testing the starter.

However: no more clicking, and multimeter readings at starter suggest the car isn't attempting to use it.

So I took out the laptop and using INPA read values for the EWS and found what it seems to be.

I'm assuming that removing the salmon relay, and the fuel pump fuse has nothing to do and that these components aren't required to start. My car is in neutral. Also using INPA's EWS module I get results suggesting that the car is in fact not allowing cranking because of a reason I don't understand:
-

EWS virginial	NO
key is sending	YES
DME line switched free	YES
Starter switched off because of :	--
reached resolutions limit	NO
P,N / US-clutch switch	YES
central lock closed	NO
BC	NO

-
Is there a clutch switch even on SMG cars? Like it needs pressure in the SMG system in order to depress the clutch pedal and unlock the starter?
Do I really have to put back the air intake (SMG reservoir) for any test?

Should I just short the solenoid S terminal to B terminal?

[sapote]

TL;DR still not working, I made some progress but I am struggling with the EWS and SMG preventing any further testing.
My question here is what does that P, N thing mean (see below, in bold), and is there a way to crank an SMG car without putting back pentosin and the airbox every time I need to attempt?

Starter not working: I should have asked to check the voltage at pin1 and pin2 of the EWS but seeing you wrote about asking the coder to "delete EWS" and so I assuming it's bypassed.

OK, to run the starter and bypass all of those N/P and SMG pressure threshold, remove the EWS and short out pin1 and pin2 using a 15A or higher fuse.
Also if the EWS disables the starter then it should not make any clicking noise when key turned to start. If indeed ews disabled the starter then even if you can crank the engine with the bypassing fuse, the DME will still not give sparks and fuel.

[E46m3zcp]

Spun the key after doign that and my starter went:

"A problem, what problem?"

It just worked.

to clarify: the clicking noise was before I removed the intake and cleaned the contacts.

then, after removing I had the SMG issue simply because I had removed the salmon relay, so the EWS wouldn’t give its “ok” due to the clutch not being disengaged.

After your hack of bypassing the EWS, I get cranking and so my conclusion is that the problem was corrosion on the terminals.

im going to reassemble the car now.

[E46m3zcp]

Well well,

After reenabling the EWS, the syptoms are back. But at least now I know it isn't the starter! (I could have just shorted EWS pin 1 and 2 and known this without removing the airbox, but now I know!)

I suspect some SMG components (like the slave cylinder) to be the cause. It looks like the clutch disengages for a brief period, but bounces back before the starter has time to spin. It sounds like the slave cylinder pushes the clutch, then lets it go immediately.
Take a look:

EWS: https://www.youtube.com/shorts/E5rugnuuR1U
SMG Digital 1: https://www.youtube.com/shorts/-_O0caQYSxM

Any reason not to leave the fuse in until I get some free time to tackle this? I guess that would mean I'd have to be more careful not mistakenly turning the key while the car is in gear (like good ol' 90's cars)

[Maxhouse97]

From a nearby thread, I’m having a similar problem with my engine not cranking. But mine clicks once, not the fast click click click that you have. That being said, I would like to troubleshoot the EWS like you have. Can you clarify what pin 1 and pin 2 you are talking about?

OK, to run the starter and bypass all of those N/P and SMG pressure threshold, remove the EWS and short out pin1 and pin2 using a 15A or higher fuse.
Also if the EWS disables the starter then it should not make any clicking noise when key turned to start. If indeed ews disabled the starter then even if you can crank the engine with the bypassing fuse, the DME will still not give sparks and fuel.

[E46m3zcp]

It's the two slots by my thumb, you will be able to insert an automotive fuse (like the ones in your fuse box) in there. No jumper wire needed. Also, conveniently, it's the only place where a fuse will fit.



The EWS can be accessed by removing the plastic under the dashboard/steering wheel on the driver side.