NEED HELP FAST - obc issue

**Bimmerfanatik** · 02-24-2006, 08:15 PM

Originally posted by Febi Guibo

hey, real quick... I had a scare induced a couple of weeks ago (my hamster-sized brain) ...have you checked your battery??

I say this because I was doing some instrument cluster work, but ran the car with the cluster removed... it ran my battery to less than 10 volts... car would have power (eg, lights etc.) but no crank... the alternator won't charge with the cluster removed...

I thought it was the obc because fiddling with the cluster harness I yanked (a little) on the OBC... but twas not the case...

check the battery...

Battery is junk, but we're running off jumper cables and my Jeep. Worked fine the other day...now nothing. Juice is not the issue - everything power works fine - wipers, windows, signals, lighting, etc. And it cranks like a champ - just no fuel.

**PeaveyBassist** · 02-24-2006, 08:19 PM

If you cant figure out the OBC problem... and the OBC is keeping the fuel pump from getting power, just run a wire from some 12v switched source to the fuel pump and ghetto rig it just to get the car to run. It wouldnt be the ideal fix, but youre not in an ideal situation either ;)

Will

**Bimmerfanatik** · 02-24-2006, 08:20 PM

Originally posted by PeaveyBassist

If you cant figure out the OBC problem... and the OBC is keeping the fuel pump from getting power, just run a wire from some 12v switched source to the fuel pump and ghetto rig it just to get the car to run. It wouldnt be the ideal fix, but youre not in an ideal situation either ;)

Will

12v switched - is that the yellow or the red for the radio? I can never remember... also, what's the best, safest place to splice into the fuel pump?

That will at least settle the OBC issue for now.

**PeaveyBassist** · 02-24-2006, 08:24 PM

Switched is yellow I think. If you have a voltmeter its easy to check. With ignition OFF, check red/yellow and if it has zero, its probably the switched one. Check the other wire and see if it has 12v. Get it? :) That will at least get the car running so the OBC issue can be fucked with later.

Will

**PeaveyBassist** · 02-24-2006, 08:25 PM

As far as splicing into the fuel pump wiring, I would go before the plug somewhere so you can still plug it in. I'm not familiar enough with the fuel pump wiring and stuff to say which wires are which and what not back there. Good luck with it though Scotty.

Will

**Bimmerfanatik** · 02-24-2006, 08:27 PM

Originally posted by PeaveyBassist

As far as splicing into the fuel pump wiring, I would go before the plug somewhere so you can still plug it in. I'm not familiar enough with the fuel pump wiring and stuff to say which wires are which and what not back there. Good luck with it though Scotty.

Will

Oy. Fuel pump=under the rear seat, yes?

**PeaveyBassist** · 02-24-2006, 08:40 PM

Yes sir. I believe on passenger side.

Will

**rs4pro3** · 02-24-2006, 08:42 PM

what you need to do is unplug the OBC harness from this plug, and reconect the chassis end to the plug. This will completly bypass the obc relay box, check to see if you have 12volt going to that green wire, if so then the OBC relay box isn't your issue.

**Bimmerfanatik** · 02-24-2006, 09:01 PM

Originally posted by rs4pro3

what you need to do is unplug the OBC harness from this plug, and reconect the chassis end to the plug. This will completly bypass the obc relay box, check to see if you have 12volt going to that green wire, if so then the OBC relay box isn't your issue.

Jesus H christ, I had it set up like that when I removed the OBC harness in its entirety. Let's play devil's advocate and pretend I've done this, and it still isn't starting. What am I missing?

PS - do you need to have the OBC harness in the car for it to run?

**rs4pro3** · 02-24-2006, 09:04 PM

no you just have to have those 2 plugs plugged together(not having the obc harness plugged in between). Have you checked yet to see if you have 12 volts on the ecu side of that plug?

**Bimmerfanatik** · 02-24-2006, 09:06 PM

Originally posted by rs4pro3

no you just have to have those 2 plugs plugged together(not having the obc harness plugged in between). Have you checked yet to see if you have 12 volts on the ecu side of that plug?

Nope - I had to run to work, but it'll be the first thing I try in the AM. Again, let's play devil's advocate and say I do get 12 volts, and also if I don't...what to check?

**Bimmerfanatik** · 02-24-2006, 09:07 PM

Originally posted by rs4pro3

no you just have to have those 2 plugs plugged together(not having the obc harness plugged in between). Have you checked yet to see if you have 12 volts on the ecu side of that plug?

PS - what happens to the plugs under the driver's side when you remove the OBC harness? Just left there? Plugged into something else?

**rs4pro3** · 02-24-2006, 09:13 PM

:D well there are 4 plugs total, 2 on the obc harness 1 on the engine harness and one on the chassis harnes, just plug the engine and chasis ones together and dangle the obc ones.
I had the relay die on my 85 325e, and just unplugged the harness from the engine harness, obc still works and the car starts.

Ok say you are getting 12 volts, now check and see with the key in the run position there is 12 volts at the green wire on the coil, then check and see that pin 87 on the main and fuel pump relays both have 12 volts, if so and still no start check and see that pin 85 on the main relay has continuity with ground with the key in the run position.

**rs4pro3** · 02-24-2006, 09:16 PM

here is a wiring diagram that may help http://www.autolib.diakom.ru:8001/CA...RAMS/fig03.pdf

http://www.autolib.diakom.ru:8001/CAR/BMW/1987/325e/WIRING%20DIAGRAMS/fig06.pdf

**Bimmerfanatik** · 02-24-2006, 09:22 PM

Originally posted by rs4pro3

:D well there are 4 plugs total, 2 on the obc harness 1 on the engine harness and one on the chassis harnes, just plug the engine and chasis ones together and dangle the obc ones.
I had the relay die on my 85 325e, and just unplugged the harness from the engine harness, obc still works and the car starts..

This is under the driver's side, correct? Pictures of the 4 plugs? So there will be two OBC plugs not used (one two prong white, one 3 prong white, if I remember) that are not plugged into anything. What are the other two plugs under there that I have to connect? Also, is the blue plug on the column just the turn signal switch plug for OBC remote control?

What relay died on you? Which harness plug did you disconnect? Any idea what two wires would have been jumped on that green plug going into the OBC box?

Originally posted by rs4pro3

Ok say you are getting 12 volts, now check and see with the key in the run position there is 12 volts at the green wire on the coil, then check and see that pin 87 on the main and fuel pump relays both have 12 volts, if so and still no start check and see that pin 85 on the main relay has continuity with ground with the key in the run position.

I saw spark at the coil, so that shouldn't be the issue. When do I check the 87 pin on the relays - while cranking, or just with the key on? And am I just making sure that pin 85 is grounded (in the run pos)?

ps - damn you know a lot about this OBC shit lol.

NEED HELP FAST - obc issue

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment