OBD2 swap ?'s

[MattM]

Well, ive been working on a OBD2 swap for the last few weeks and have a few questions that i cant seem to figure out.

1996 328i donor car...

1. Fuel consumption, Both x6000p9 and x6000p46 show as fuel consumption INPUT to the DME.... P46 goes through the x6031, whereas P9 goes through X20P24. Both go to the instrument cluster... and i cant find any fuel consumption output.....

2. Fuel tank pressure sensor.... can i just put a T on like the vent line back to the tank for this?


Im sure i will have more ?'s, but thats all for now....

[Lawson509]

2. Fuel tank pressure sensor.... can i just put a T on like the vent line back to the tank for this?

As far as I know you can't do that. The OBDII systems usually always have a pump, solenoid, and sensor unit attached to the tank. It pumps air into the tank and then measures if there is any pressure bleed-off to indicate a leak. So if you don't have the pump or solenoid, it will throw an error code. Not 100% on how that applies to your setup, but that's how most systems for EVAP work.

As for your fuel usage, I did an 1999 OBDII and that system ran a wire from the ABS controller and then to the instrument cluster. I don't know how the system works with your setup....

Good luck tho

[MattM]

As far as I know you can't do that. The OBDII systems usually always have a pump, solenoid, and sensor unit attached to the tank. It pumps air into the tank and then measures if there is any pressure bleed-off to indicate a leak. So if you don't have the pump or solenoid, it will throw an error code. Not 100% on how that applies to your setup, but that's how most systems for EVAP work.

As for your fuel usage, I did an 1999 OBDII and that system ran a wire from the ABS controller and then to the instrument cluster. I don't know how the system works with your setup....

Good luck tho

thanks, the 328 i have uses Exhaust back-pressure to pressurize the tank via an electric valve. I have that system, just trying to figure out how im going to hook it all up...

Does Anyone have a complete fuel system plumbing diagram from an obd2 E36? Realoem is pretty patchy...


are you using the E36 ABS/ACS unit? E30 unit doesnt need any fuel consumption feed from what i can find... can you explain that a little more?

[luckysnafu]

I have a 96 m52 in my e30 so I've been through all of this, pretty easy to sort out.

Why are you so concerned with the e36 fuel system plumbing and venting? You can just delete any components used in the e36 fuel venting. The ECU will throw an error code but it will not affect performance at all. You can also get TRM (the racers market) to delete the fuel venting and pressure sensor from the ECU so it won't throw the code.

For a late model car fuel consumption goes from e36 x20 pin 24 to e30 c101 pin 8.

For an early model car fuel consumption goes from the c104 connector above the glovebox. c104 Pin 3 (white/yellow wire) connects to e36 x20 pin 24. Engine speed also connects from the c104 pin 1 (black wire) to e36 x20 pin 20.

Why do you need the e36 abs/acs unit?

[MattM]

i have OCD and want its to be as factory as possible...lol

im using the E30 ABS unit, but lawson mentioned something about fuel consumption to the ABS system.

[luckysnafu]

You don't need the e36 ABS unit to get fuel consumption and there is no other reason it would be needed for the swap.

You can use your e30 abs unit. It will work the same as before the swap, unless you have a late model e30 then you need to power (ignition switched 12+) c101 pin 20.

[MattM]

i think ive got it, when i turn the key i can hear relay clicking in the ABS unit.


one more question, automatic harness, what DME pins do i connect with OBD2(96 328 ) ?? it doesnt seem like the pins mentioned for obd1 make any sense in the ETM's....