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1997 740I intermittent no crank no start... Very wierd problem pretty sure it an electrical problem but I have no idea where to even start...

148 Views 4 Replies 4 Participants Last post by  u.nanimous
I took it to a import shop and they told me it needs to go to the dealership, that the Ews and key came out of synch... But just two days later it fired up and once it running it runs like a champ.. please help...
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Did you use a different key? It will no resync itself without BMW software. I'm wondering if there wasn't just a low battery issue. This car is very particular about voltage.
Thanks for the reply... I greatly appreciate any help I could get on this matter!! N No I don't have another key... And I just today put in a brand new H9 battery die hard from advanced auto parts and still no crank.... Is there a 2ay to pull up codes even if the check engine light is not on, without a OBD2 scanner?
You probably aren’t going to be able to get codes for this potential issue with a standard OBDII scanner. OBDII is only for emissions related. This will likely be in another module. Best bet is to use EDIBAS/INPA or ISTA which are BMW systems you can get for a laptop etc.
or, if you are located by a forum member with it, you might get a friendly free scan… but you would have to either provide or update your location in your profile and hope there is one around you.
Is this a no crank no start? So you turn the key and nothing. It could be a dying starter… test with a “mechanic tap”. That can jostle it to a place where it will start.
Is it a crank, no start? Could be a fuel pump, vacuum/MAF, crank position sensor, etc. issue.
Is it intermittent depending on weather, especially rain the day before? Could be an electrical distribution issue form the relevant passenger floor area getting wet.
Any more details on the symptoms that you are willing to provide? Depending on the symptoms, we may be able to steer you to a more manageable position.

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If it is "no crank" then there is no point to say "no start", that's a separate problem as TAB mentioned above.
Being intermittent it can't be the sync as Mayor said, but relating to the key it could be the ignition switch. Is there anything else you notice that isn't right when you turn the key? Search YouTube for "BMW visor test".

Being a 1997 at least it is OBD-II, but without a modification the port inside the cabin only talks to the DME. To help diagnose other issues you'll need software as TAB suggested and an adapter for the Pac-Man port (~2.5" round cap on passenger side under the hood).
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