X3 3.0 Backfiring and missfiring

[skylined_gtr]

Hi All,

Hoping someone can give me some guidance. I've got a 2004 (54) X3 3.0 Sport, Auto, been a great car but has suddenly developed a fault.

Been parked for a couple of weeks, went to start it and wouldn't stay running, it went to 1k rpm then dropped almost instantly.


Tried again but this time gave it some pedal to about 2k, was really struggling to stay alive and backfiring through the inlet manifold.

Rev up to 4k, the backfiring is reduced (i.e. a lot less frequent), but again struggling and the odd misfire.


Read the codes using INPA, it came up with Air Mass Meter and Thermostat Map Cooling Control. Cleared the codes, tried it again without the Air Mass Meter but got exactly the same results (as described above). The error codes haven't returned since. Bought a new Air Mass Meter anyways to try it out but same results.

I ignored the Thermostat Map Cooling Control (I assume this is the ECU water temp sensor?) Could this be the trouble?


Pulled the spark plugs out, coated in fuel so it looks like it's dumping a load of fuel in? Not sure. I'm thinking massive air leak somewhere (although I can't hear one) but I can't think where to look. Are there common failure points on this engine?

Help!

[marti]

Could well be the fuel regulator if its banging that much fuel in.....disconnect the battery for 30mins and then try again...brown (or red) off first and back on last...

[skylined_gtr]

Thanks, tried that last night, no difference Any other suggestions?

[yes_its_neil]

Unplug the MAF if you haven't tried that already. Will run with default settings, rather than possible corrupted settings from a dirty or faulty MAF. I just replaced mine to fix irregular idle and even occasional stalling. As soon as I disconnected the MAF it ran fine. Was tempted to leave it that way, but decided to replace the MAF. I tried cleaning the original, but it didn't fix the problem.