ENgine management warning light (3.0l Petrol, manual)

[ianst0028]

Benengo did you find out what was wrong ??

[Smeeagain]

He's already answered that question if you read the thread

[ianst0028]

not that i've read ..... there is mention of the codes being cleared and then returning

[ianst0028]

[quote="Benengo"]
[quote="Smeeagain"]
[quote="Benengo"]
My 2001 X5 has an engine warning light is on :0(

i've got it booked in on monday but is there a checklist of simple things I can look at before i take in?

So far I'm guessing:
fuel cap
spark plugs and leads
oil cap

What can be done without specialist tools or a diagnostic comp?

Regards

Benengo
[/quote]

Benengo, how did you get on when you took it in yesterday?

Smee
[/quote]

As above really... with these faults:

P0171
P0174
P1620

The chap at the garage cleared all of them and the light went out; however, following first contact with the enemy (my wife’s driving and towing a horse box!) they are back on this AM!
[/quote]

[themoog]

Didn't I say air leak? ( breathes on finger nails then rubs them on chest)...

[Horizon]

[quote="Horizon"]
I heard of a split air intake hose after the MAF, usually on the hose at the junction of the idle valve junction, causing a fault light, s it confuses the Lambda sensor. Just guessing by the way. Spraying easy start on the hose can induce an increase in revs, signifying a vacuum leak.

[Benengo]

So I've been up to my elbows in X5 this morning and ive taken all of the air intake system out. Happily it all looked pretty solid so I gave the throttle body a good soaking in carb cleaner and put it all back together however, its still running lumpy. It seemed to be running pretty smoothly whilst i had the intake etc off.
I guess as there were no obvious holes, leaks, tares etc this is unlikely to be the problem; however, i assume it could be an issue with the MAF? Do they fail often? If i have to replace are the significantly cheaper non OEM parts up to the job?

Of course, if it's not on the air intake side of house, the other suggestion is the crank case breather. Now I dont mind getting my hands dirty, but from my first impressions, inspecting/replacing this part looks like a whole new ball game!? Anyone done it at home? how long and how difficult was it? is there a write up anywhere?

[Horizon]

Is there evidence of a high suction rare as per the video when removing the oil filler cap ?
If the MAF is unplugged it Puts the ECU settings into a default state, so ignoring the alternating MAF signals.
The MAF could be faulty, expensive trial and error though, most say get OEM, Bosch sensors as the cheap ones are not good.
The MAF monitors how much air is being drawn in to the engine and regulates the mixture with the help of the O2 sensors in the exhaust. If more air is allowed into the engine after the MAF it can't regulate properly, so the extra air causes the engine to run lean, triggering a fault code, which you have.
As said a disconnected MAF reverts to a default setting . If you remove the boot with the MAF plugged in it won't run properly. Check the DISA valve for air leaks too, they have been known for orings and the actual workings to go.

[Benengo]

[quote="Horizon"]
Is there evidence of a high suction rare as per the video when removing the oil filler cap ?
If the MAF is unplugged it Puts the ECU settings into a default state, so ignoring the alternating MAF signals.
The MAF could be faulty, expensive trial and error though, most say get OEM, Bosch sensors as the cheap ones are not good.
The MAF monitors how much air is being drawn in to the engine and regulates the mixture with the help of the O2 sensors in the exhaust. If more air is allowed into the engine after the MAF it can't regulate properly, so the extra air causes the engine to run lean, triggering a fault code, which you have.
As said a disconnected MAF reverts to a default setting . If you remove the boot with the MAF plugged in it won't run properly. Check the DISA valve for air leaks too, they have been known for orings and the actual workings to go.
[/quote]

Just checked for suction when removing the oil filler and there is nothing significant (which I suspect is a good thing!) I then disconnected the MAF (at the MAF) and the engine immediately gave me some revs and a constant idle (no hunting and no longer lumpy). on reconnecting the engine hunts for about 30 secs before settling back to a lumpy idle.

I think I will get a replacement MAF (a cheap one as times are tight!). Do I also need to look at replacing the O2 sensor at the same time?

[Benengo]

By the way thats everyone for all the responses. Much appreciated (especially for a newbie!)

[Horizon]

[quote="Benengo"]
[quote="Horizon"]
Is there evidence of a high suction rare as per the video when removing the oil filler cap ?
If the MAF is unplugged it Puts the ECU settings into a default state, so ignoring the alternating MAF signals.
The MAF could be faulty, expensive trial and error though, most say get OEM, Bosch sensors as the cheap ones are not good.
The MAF monitors how much air is being drawn in to the engine and regulates the mixture with the help of the O2 sensors in the exhaust. If more air is allowed into the engine after the MAF it can't regulate properly, so the extra air causes the engine to run lean, triggering a fault code, which you have.
As said a disconnected MAF reverts to a default setting . If you remove the boot with the MAF plugged in it won't run properly. Check the DISA valve for air leaks too, they have been known for orings and the actual workings to go.
[/quote]

Just checked for suction when removing the oil filler and there is nothing significant (which I suspect is a good thing!) I then disconnected the MAF (at the MAF) and the engine immediately gave me some revs and a constant idle (no hunting and no longer lumpy). on reconnecting the engine hunts for about 30 secs before settling back to a lumpy idle.

I think I will get a replacement MAF (a cheap one as times are tight!). Do I also need to look at replacing the O2 sensor at the same time?
[/quote]
O2 sensors ( Lamda sensors ) usually throw a different fault code when faulty.

[ianst0028]

I had the same codes and problems when I bought my 3.0 last yrar
I tried everything new mass air flow new plugs new coils all 4 lambda sensors
It ended up being the crankcase breather system.... Took a couple of hours to change it but after clearing the codes I've never seen lean running codes since

[Benengo]

[quote="ianst0028"]
I had the same codes and problems when I bought my 3.0 last yrar
I tried everything new mass air flow new plugs new coils all 4 lambda sensors
It ended up being the crankcase breather system.... Took a couple of hours to change it but after clearing the codes I've never seen lean running codes since
[/quote]

Is there a write up or step by step guide anywhere on how to do this?

[ianst0028]

http://blog.bavauto.com/5434/bmw-m54-6- ... 525i-530i/

febi part number for the kit is 46303 but the oil drain pipe is wrong so you'll need to order a febi 45358 hose too (leaving you with one spare useless hose)
stripping it all down is really easy except for the hoses will all break and then you realise that you've got to finish the job
putting it back together is more fiddly one of the hoses is a twist lock and it was a massive pain to get it to work
when / if I had to do it again i'd probably take the inlet manifold off (sounds like a nightmare but i found it easier to do than the CCV)


BTW when i took the febi parts out of the box they had all had the BMW part numbers removed so I was pretty certain i was actually fitting genuine

also when you take the 2x torx screws from the valve use a magnetic bit (voice of experience here) because if you drop one its a nightmare

[ianst0028]

there is also a youtube vid that i used ..... i know its not on an x5 but its very helpful

https://www.youtube.com/watch?v=YWXtiCwRH-k