Fuel Pump and O2 Sensors

[JaamesE36]

Hi all. I’ve got a bmw 316 with a 323 engine, it’s a drift car bottom line. I bought the car last week so have no clue about these cars yet. The battery went flat, I charged it up all okay and it went flat again, so obviously there is a drain somewhere. I noticed that when you put your hand on the rear bench there is a whirring buzzing vibrating feeling/sound, this says to me the fuel pump is constantly running (engine off key out) which I’m guessing this is my drain.

 

I done a Snap in Scan just to check for any faults and it brought up o2 sensor heater problem. I cleared the codes, scanned again (before starting or anything) and o2 sensor codes won’t go away. Now I read somewhere someone with the same issue and that they are linked however he never come back to the thread. Any help?

[Bimmer Owners Club]

Hi James....welcome to the Forums

Sounds like a short circuit which is energising the pump relay.
I would disconnect the lambda sensor connector and see if this changes anything, if not the change the relay (may be another one in the fusebox that you can substitute to see if it makes any difference.

Let us know what you find out

[JaamesE36]

It failed to start earlier. Fuel pump wasn’t priming. Opened the bonnet wiggled every fuse and relay and it primed and started, also when engine was off fuel pump/rear bench wasn’t vibrating. Battery going flat is my main concern so we’re see how that pans out now. 

[JaamesE36]

Battery was flat this morning. Useless with electrics. No idea where to start 

[Phillip Rowe]

Battery could need replacing. If so it would need to be coded by BMW. Have battery tested, if a new one needed buy one and then get bmw to code it.

 

[JaamesE36]

What even on a 97’ E36? I don’t think the car has an immobiliser let alone a battery needing coding, it’s not even OBD2 haha. Battery has been relocated behind passenger seat. Everything cut out from the inside etc apart from a rollcage and dash there’s nothing to it. Wouldn’t think a battery would need coding in a 22 year old car 

[Bimmer Owners Club]

Just thinking that if you've cut everything out of the car then I would be tempted to wire the fuel pump directly through a cut off switch and even if it is drawing power then you can switch it out completely

 

[Greydog]

Good thinking Trevor, if it is a drift/competition car won't the scrutineers want to see a master kill switch accessible from outside the car ?

[JaamesE36]

Went and got the battery tested. Replacement advised. The CCA is down under half so that’s my issue I believe. Thanks again. Posting a new thread on another issue. Here we go again!