Year of Manufacture *: N reg Engine Size and Code *: 2.8 ( Optional ) Scanner Used: X431/Multiscan ( Optional) Fault Codes: 68 (Fuel tank vent)
MOT fail on emissions (Not by much)
Actually runs great, Obviously has been a problem for some time however since although it passed last years MOT this was only because (Somehow) it had been tested (and passed) as a pre-cat car??
Live data seems credable across the board but both lambdas are stuck at 4.9v and the live data also indicates running on open loop. Thermostat seems to open early and engine struggles to get past 83C
With oil cap removed (to generate weak running, confirmed by gas tester) ECU still reports 4.9 V for the lambdas, ECU even reports 4.9 volts with the lambdas disconnected?
What I havent done (and should have) was test the open circuit signal signal from the lambdas. but I will be going back to have another look tomorrow.
I am planning to replace the thermostat and see if that makes any diference (I am not holding my breath however, but I seem to remember reading that the BMW ECM wont enter closed loop below somewhere around 80C so there could be a borderline issue there)
Now, My questions are...
1) Can anybody confirm (or otherwise) the ECM stratagy regarding temperature?
2) Might there be an ECM issue regarding the fact that the live data still reports 4.9V with the lambdas disconnected! (IE Has anybody seen this one before)
3) Any other suggestion for tomorrows campaign of action??
Well, today I tried running the vehicle with the Lambda sensors disconnected.
I got 0V from the sensors. (with sensors disconnected, Live data still recorded 4.9V)
with sensors disconnected, the signal wire on the main loom was at 4.9V
with signal wire on main loom earthed, live data reported 0V! (So I am assuming that it is reporting signal voltages correctly)
How do these BMW spec sensors work? Do they generate a voltage like the "Normal" lambda sensors or do the act as an earth signal with the ECU defaultin to 4.9V under fail conditions???
Re: Update!
Posted by ian slattery on February 16, 2012, 9:40 am, in reply to "Update!" Ian Slattery
I don't know what kind of sensor is fitted to your bmw. With 5v on a signal wire i would try to find out. It may have a Titania sensor, which needs a voltage to operate. Take a look at the pico website. regards ian
on February 14, 2012, 9:44 pm, in reply to "