One day she's fine, the next she's dead. Second opinions?

[HugeGernsback]

Finally got the baby out of the garage the other week since the weather is starting to break here in PA. Drove my E34 for two weeks with no problems. Didn't even hesitate to start after being dormant for 3 months. I go to start it yesterday morning and nothing. The dash lights, radio, headlights etc. work just fine, but the car didn't even try to crank. I charged the battery overnight thinking it may be dead... even after working fine after 3 months off . Tried again this morning with a fresh charge and still nothing.

From my research, I'm finding that it could be a myriad of things. Anywhere from the starter, alternator, fuel pump, the whole way down to the fuses or relays.

I've done part of my due diligence so far, and will continue to do so over the next few days, but as with anything BMW, I would like some second opinions from you dear forum members

I plan on voltage testing everything when I get home to ensure that the battery is still good, since I'm not entirely sure how old it is.

Thanks!


Edit: the car is NOT throwing any codes other than 1444

[The Chauffeur]

As you already said, it could be a myriad of things... I'd first check the crankshaft position sensor

[HugeGernsback]

As you already said, it could be a myriad of things... I'd first check the crankshaft position sensor

Would this throw an engine code? If so then that is not my problem

[The Chauffeur]

Don't quote me on this, but I don't think it would.

[HugeGernsback]

Don't quote me on this, but I don't think it would.

Forgive me for my unfamiliarity, but how would one "check" this sensor? I know where it's located and such, but how would I diagnosis this?


Edit: Nevermind, I found out how. Thanks!

[demetk]

Use the diagnostic connector pin 11 to crank. If it cranks then check the shift lever switch for a park/neutral signal and both the starter relay and the ignition switch for powering up the black/yellow starter wire at crank.

Have you downloaded the electrical wiring diagrams for your car?

[HugeGernsback]

Use the diagnostic connector pin 11 to crank. If it cranks then check the shift lever switch for a park/neutral signal and both the starter relay and the ignition switch for powering up the black/yellow starter wire at crank.

Have you downloaded the electrical wiring diagrams for your car?

I do have them, but have never needed to look at them yet so I'm unfamiliar. Thanks for your input though!

[tschultz]

Use the diagnostic connector pin 11 to crank. If it cranks then check the shift lever switch for a park/neutral signal and both the starter relay and the ignition switch for powering up the black/yellow starter wire at crank.

Have you downloaded the electrical wiring diagrams for your car?

I was thinking the same... Likely auto trans safety switch

[HugeGernsback]

Sounds roughly straightforward. Can all of this be accomplished with just a multimeter?

[Arman524]

I've been experiencing the same exact problem, my car at times will give no response, the dash and radio will turn on but windows and sunroof won't respond. As I try to start the car I get no reaction, no cranking nose nothing. Sometimes the car will work with no issues and once it starts I could use it throughout the entire day.

I replaced the starter, checked all of the fuses that connects to the battery, checked all of the wires that connects to the ignition switch but can't figure out what the problem is.

[HugeGernsback]

Update: battery is fine

Any way either of you can give me a little more explicit set of methods for testing this? I've never touched the wiring for this car so I'm not sure where this stuff is located. Sorry for being a noob.

[demetk]

If you have a meter then you can test a couple of things directly at the starter relay (K1) in the front power distribution box. The relay should have the pin numbers stamped beside each pin.

Starter relay pin assignments.
#86-relay coil trigger wire from the shifter neutral safety switch.
#85-relay coil ground wire connected to body ground. When the shifter is in park or neutral and the ignition is turned to ON the starter relay will get activated on with a audible click.

#30-start wire from the ignition switch.
#87-start wire going to the starter. #30 and #87 get connected together when the start relay gets activated on with the ignition turned to ON. Then when the ignition is turned to START, power will flow from #30 to #87 and to the starter coil thus activating the starter.

A couple of tests.
1. Does it click with the ignition turned to ON?
If not, pull the starter relay and check for power at pin 86 of the starter relay socket with ignition ON.
If no power, test the neutral safety switch at the shifter.
Have you tried starting the car in neutral?

2. Does pin 30 of the starter relay socket have 12 volts when the ignition is turned to start?
If not, test the ignition switch.

If in doubt, ask.

[HugeGernsback]

If you have a meter then you can test a couple of things directly at the starter relay (K1) in the front power distribution box. The relay should have the pin numbers stamped beside each pin.

Starter relay pin assignments.
#86-relay coil trigger wire from the shifter neutral safety switch.
#85-relay coil ground wire connected to body ground. When the shifter is in park or neutral and the ignition is turned to ON the starter relay will get activated on with a audible click.

#30-start wire from the ignition switch.
#87-start wire going to the starter. #30 and #87 get connected together when the start relay gets activated on with the ignition turned to ON. Then when the ignition is turned to START, power will flow from #30 to #87 and to the starter coil thus activating the starter.

A couple of tests.
1. Does it click with the ignition turned to ON?
If not, pull the starter relay and check for power at pin 86 of the starter relay socket with ignition ON.
If no power, test the neutral safety switch at the shifter.
Have you tried starting the car in neutral?

2. Does pin 30 of the starter relay socket have 12 volts when the ignition is turned to start?
If not, test the ignition switch.

If in doubt, ask.

Thank you so freaking much my man.

I'll report back after I've tested this out.

[HugeGernsback]

So, as of this morning, my issue has been solved! One loose wire and one bad relay. Both have been changed and I'm back running strong.

Thanks to everyone and their advice/help. Really appreciate it!

[shogun]

So, as of this morning, my issue has been solved! One loose wire and one bad relay. Both have been changed and I'm back running strong.

can you explain that more in detail, which wire, where does it go, which relay?
That will help others in the future.

[fo3]

Lucky!
I've been going through similar problems and for mine it seems the ignition switch. I last had the problem on the on 20 Feb. I had to use diag #11 to crank it on the 20th and have since driven the car every day multiple starts and for the past 5 days has been fine again. And it worked fine from 28th Jan to 20 Feb. It's so intermittent.