New MAF, now won't start unless unplugged?

DukeDiablo · #1 05-12-2009, 09:41 AM

Dear Forum-

'01 X5 4.4i, 107,000 miles...

After a bunch of repairs lately, pre-cat 02's, fuel filter, valley pan gasket, intake gaskets....

I was told by a local independent german service shop that I needed to change my Mass Air Flow sensor to correct a drivability issue and jumpy or not sustainable idle when hot and restarted.

So I got a Bosch (Beck Arnley) from RockAuto.com today.

Put in on and now it won't hold an idle at all... even if I use the throttle. If I unplug the MAF it starts right up and acts fine at idle, I haven't tried to drive it like that yet.

Any ideas? I already got what I thought was a bad MAF from eBay so this go around I decided to get what I thought was a good replacement from RockAuto.com.

No Service Engine Lights either.

Thanks for any help.

Oh and I tried the Throttle Adaptation Procedure and it actually idled for 30 seconds before it went into a 500RPM jump up and down and finally died.

Sincerely,
Jim Kennedy

Sponsored Links

Wayne's World · #2 05-12-2009, 10:38 AM

Try pulling the negative battery terminal. This may clear the ECU. I'm not sure of a way to clear the ECU otherwise but the idea is to let it relearn the fuel trim from scratch.

DukeDiablo · #3 05-12-2009, 03:12 PM

Thanks Wayne-

Although it's always a fun time getting to the battery... that did the trick. After I disconnected the battery for about 30 minutes, I went out, reconnected and then performed the Throttle Adaptation Procedure again... and it worked perfectly.

I guess just like Windows... my BMW needed to be rebooted.

Yall have a great week.

-Jim

Wayne's World · #4 05-12-2009, 03:17 PM

No prob man!

I'm in IT. And I have the same love/hate relationship with my PC as I do my BMW. hahaha. It's fun though!

simoncpw · #5 05-12-2009, 07:54 PM

Hi Jim, can you let me know where I can find the Throttel Adapation Procedure?

Thanks.

(Edit: oops.. never mind... I've found did Thanks).

Quote:

Originally Posted by DukeDiablo

Thanks Wayne-

Although it's always a fun time getting to the battery... that did the trick. After I disconnected the battery for about 30 minutes, I went out, reconnected and then performed the Throttle Adaptation Procedure again... and it worked perfectly.

I guess just like Windows... my BMW needed to be rebooted.

Yall have a great week.

-Jim

DukeDiablo · #6 05-13-2009, 07:52 AM

Well, it's back.

I guess all I did was delay the inevitable.

My Actron Scanner is telling me Bank 1 and Bank 2 "Too Lean" again.

Which I believe once again points back to the MAF when they set off together like that.

Does anyone know a way to test the MAF by using a multimeter or something. Some kind of resistance reading? I just can't believe it's still the MAF after trying two new units.

Any advice would be appreciated.

-Jim

Wayne's World · #7 05-13-2009, 07:56 AM

Sorry to hear Jim. The next likely culprit other than the MAF is a vacuum leak. Popular suspects are intake boot off-shoot elbow (goes to the ICV just before it goes to the throttle body), valve cover gasket, oil cap (sealing ring on the underside), spark plugs (not torqued to spec) and potentially any of the hoses going to and from the Oil Separator/CCV.

Edit: Is it even starting at all?

Whoopitupinmo · #8 05-13-2009, 07:59 AM

Same issues here so any additional help on how to fix would be great

DukeDiablo · #9 05-13-2009, 08:02 AM

Wayne-

Well I've changed plugs and I'll check the torque on them again...

The intake gaskets were just changed, so I'll keep that in mind...

The Oil Cap is original, I'll see what that looks like...

I'm hoping it's the intake elbow, but I was thinking that was more of a problem with the 3.0 liter motors?

I guess it's just going to take some trouble shooting time with vacuum lines.

Thanks,
Jim

Wayne's World · #10 05-13-2009, 08:05 AM

OK - I have a 3.0 motor and that's been my experience.

Does it start with the MAF plugged in?

If it doesn't and it's starting with the MAF unplugged, that may actually be generating your errors.

Troubleshooting with all variables is not a good way to start. I'd say pickup an original BMW MAF from the dealer and plug that in. If it starts right up, then you know you've got bad MAFs - which isn't entirely impossible. If it doesn't work, you can always take it back.

If you do suspect you have a vacuum leak, check the usual areas but if you don't turn anything up, take it to someone who can perform a smoke test on it. That will save you alot of grief.

Sponsored Links