Quote:
Originally Posted by mweisdorfer
Quote:
Originally Posted by mcaval465
Hi all,
I have a 2007 335i E92 AT with 160k miles currently in a no start condition due to what i think is an electrical/grounding problem. Looking for any help I can get before I take it to a shop.
I'll do my best to describe what happened and what i've done so far:
The initial problem was a sudden no start about 3 weeks ago after work. The only sign of it dying up to that point was a slow start in the morning, but i brushed it off since it was a cold day. I tried jumping initially and no luck. After a bit of research I read about grounding straps breaking and got it to start by connecting the jumper across the chassis ground to the engine. Unfortunately my house was about an hour away, and since the battery couldn't charge about 3/4 the way back things started to act crazy since voltage was probably dropping. I ended up having to cruise to a stop roughly 1/2 mile from my house since the ABS and the trans were giving warnings and everything was flickering off. At that point a friend and I just slowly towed it back using some straps, putting it in neutral, and connecting it via the tow hooks to another car. (in hindsight just getting a tow back originally rather than jumping it might have saved me from further electrical issues but in the moment it seemed like the way too expensive option) Below is the list of the things i proceeded to change/check with no luck:
I immediately replaced the engine ground strap. Before, when i pressed ignition, there was no sound coming from the starter/solenoid. After replacing, you could hear the solenoid/starter give a strong click and spin for half a second, but then die out.
Charged battery.
Checked OBD codes. Initially, there were tons of codes because of the low voltage at the battery. After clearing and trying to start a few times no codes popped up.
Replaced Starter. Spun it around a couple of times with a harbor freight bump starter as well to make sure it worked when it was in the car. Also proved that things are moving and the engine isn't locked
Replaced Battery. I replaced it with a BMW battery from the dealer. Since its still sitting in my garage, i havn't been able to register it. Waiting to do that at the indy shop or dealer if i can get it running.
Disconnected IBS Cable. Also read on several forums this was a possible cause.
Replaced the black CAS relay in the fuse box. I saw on youtube this was a potential solution and said why not try. Doesn't seem like a CAS problem since the dash lights up as normal when i press ignition - just has check engine light. I've also tried using my other key.
Moved it from park to neutral. I've read on other forums this is a test to see if the brake pedal sensor works which may stop the car from starting?
The most notable thing is the moment I hit ignition, the voltage drops across the entire car. From ~12.4 V to 9 V or less, you can even see the cabin lights flicker. Also notable is that the + cable that connects to the starter near the ECU and B+ post fluctuates in voltage randomly when the car is awake. It seems like when the car is awake every ~5-7 seconds it dips to 8 V and then back to 12.4 V. The other two positive posts/connections have a solid 12.4 V. I also measured from chassis ground to the engine and the alternator case and get a solid 12.4 V.
My next step is to remove the airbox again and see whats going on at the alternator and ground terminal to the starter. Any recommendations on what else i should be trying would be greatly appreciated. I believe its a grounding issue somewhere, but i'm at a loss for where since I've replaced the engine ground strap.
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Did you change out the ground strap underneath the drivers side? |
Hey I'm have a simmer problem my mechanic said that I have ground and continuity but there is no positive single to the starter for it to turn over when we use a probe and give it power it starts fine does this sound like a cas problem or something else