2002 X5 won't start after driver side brake pad & rotor change

beamer9 · #1 03-21-2015, 01:51 PM

Dear X5outpost members,
I recently changed my front brake pads and rotors. After I disconnected the brake pad sensor my cars electronics went haywire. I attempted to start the car to move the steering wheel the engine was vibrating, and in about2 seconds it sputtered out and died. Now the electronics are acting like a flying saucer is hovering above, ABS light on, acting like battery is dead. I finished brakes, then checked battery, and it still reads fully charged. At first the car cranked and wouldn't start, now it doesn't crank, and alarm sort of turns on then randomly goes off and most systems including outside lights are clearly barely getting power. Any idea what is going on?

Thanks, Aaron

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beamer9 · #2 03-21-2015, 04:18 PM

Some additional history... About a year ago when I replaced the front suspension I discovered if I wiggled the brake sensor wire it would occasionally trigger all 4 windows to open half way. Has anybody else expierenced bizarre electrical behavior like this?

jgold47 · #3 03-21-2015, 05:49 PM

How old is your battery?

Actually, I don't care. Replace it anyways and report back. Step one with all BMW electrical gremlins is a new battery.

beamer9 · #4 03-21-2015, 06:01 PM

The rear light thing, has been an issue since I bought the car. I've replaced more of those sockets than I can count. Wiggling the light does produce those behaviors, and it did happen to be out again yesterday to which I promptly wiggled again to get the light working.

Battery is a little over a year old.

upallnight · #5 03-21-2015, 06:34 PM

Did you just buy this X? Did you check it to verify that it wasn't a flood car?

David.X5 · #6 03-21-2015, 07:10 PM

Sorry. Electrical gremlins are the worst to trouble shoot.

I would consider the connections at the alternator which is close to that location (at least on the 4.4). Or something in the harness - does wiggling the engine harness change any of that?

I paid almost $1000 for an Indy to track down (that's where the time was) and repair a crimped wire in the engine harness. probably should have picked up a low mileage one on eBay instead.

David.X5 · #7 03-21-2015, 07:15 PM

Have to agree it can't be those actual sensors. It's a real "dumb" thing that is either open or has continuity. The engine will run fine without it. Likewise the wheel speed sensor.(more complicated sensor). You will get the trifecta if it's broken, but it won't affect engine running.

So think about what might move when you pulled on them, etc...

beamer9 · #8 03-21-2015, 07:15 PM

The battery was dead, but now the ignition turns over but no gas seems to be making it to engine... I am a little embarrassed give the obvious symptoms.

Useful knowledge: Don't test your battery charge from under the hood using a charger. Mine gave a 100% charg e reading. I decided to disconnect battery in back due to some posts I read suggesting this, and since I already had it disconnected clipped my charger on to check for reading and it registered around 20% charged. Thanks for your help!

Sincerely, Aaron

David.X5 · #9 03-21-2015, 07:22 PM

Sorry. Keep thinking about this - is it possible the battery discharged while you were working on it (dome light on overnight, etc)? Try to get a voltage reading with the car off and while cranking (if it cranks) and when it starts. You may have dropped below the threshold (around 11 V) where the ECU won't even try to crank. No idea how that ties into the rough idle, but could be two issues...

beamer9 · #10 03-21-2015, 11:28 PM

I think an electrical short in the brake pad sensor caused something else to trigger that drained the power. Here is where it is at:
The night before I worked on the driver side brake rotor, and pads I worked on the passenger side. I know the battery was charged then, and I know the engine was getting gas, because I drove the car about half a mile, more than the distance it would take to run out of gas if fuel was not being pumped. Then I topped the engine off with oil, because it was about a quart low (it burns oil, I don't think it leaks it since I have had the bottom shield thing off for a couple months). Yesterday when I attempted to turn the car on to turn the wheel it started for a couple seconds and died.

I suspect the cause of the turning over but not starting may be fuel related. its sounds like the engine is getting no gas. The car worked before I jacked it up. I can't say if I took off the rotor or not before I tried to start, but I did have the caliper off, and the brake wear sensor pulled.

It seems to me the culprit is either the sensor, and a short somewhere, or jacking the car up on the driver's side door could of damaged an internal fuel line, or wire for the fuel line? The last and hopefully least desirable could be a shorted fuel pump regulator.

Any suggestions on steps to follow to find out why it isn't getting gas?

Thanks,

Aaron

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