Idling and acceleration 20001.9m43

[dazthephot]

Hi guys, here we are again with a poorly zed. This time i'm thinking camshaft sensor, reasons being:

will start but won't tick over
can't get the revs past 2000 so can't drive it

my Peake tool is showing 2 lambda related faults but i'm just not sure, the fault started when i went out one day and had to brake hard, it started spitting and farting and i just made it home.

any thoughts?

[Robert T]

First guess would be camshaft sensor, which doesn't always register with the ECU. Mine had exactly these kind of symptoms - would fire up and rev, but wouldn't maintain the revs and was spluttering and coughing and sounding really grumpy. I wouldn't have run it, but I was on the A556 at the time - not the best place to break down - I limped off the road and called the AA. Annoyingly it behaved itself after the AA man had a fiddle, but BMW diagnosed sensor the following day and has been a good as gold since.

Cheers R.

[Mike Fishwick]

Before doing anything expensive, take the cam sensor out and clean it - they tend to attract metallic debris, which masks the sensor.

It's on the front of the engine, in front of the cylinder head.

[dazthephot]

i cleaned it today and put it back but no difference. it won't tick over now so i'm gunna unplug the lamda probes one at a time then both and see what happens. i'll keep you posted. my thinking is that if the engine ticks over and revs with the lambda's unplugged then they are faulty. if not, i'll replace the cam sensor first as it's the cheapest option. i've tried walker lamda's before and found them to be poor so i'll go for Bosch. stealer's price for a probe is circa £140 each! £70ish for the sensor. fingers crossed it's the sensor, it just confuses the issue with the peake II tool showing a post cat and regulating probe fault.

[PORTMYSTER]

I had this problem a few months ago, car exhaust poped and revs was up and down and when driving would not put power down. My garage on their machine found 2 lambar faults and then BMW found coil pack problem but in the end it was the air mass sensor and this fixed the problem, around 170 pound but I would take it off and clean that and see if it makes a difference.

[dazthephot]

well well, it just shows you why this forum is a great source of info. i just unplugged the MAF sensor and low and behold the car started straight away, without accelerator and ticked over and revved no problems.
i took it off and tried to clean it but there isn't really anything you can do except blow it out. funnily that fault when unplugged is on the same table as my lambda faults, could this be causing a false error?

[PORTMYSTER]

Yep you realy carnt clean it with the new MAF the sensors should go off they did on mine but i;m no mechanic hope this has solved your problem

[dazthephot]

All hail to the forum!
Found a link to cleaning the MAF, pulled it out, cleaned it as per instructions, put it back - runs a treat. Cleared the codes now so waiting to see if those pesky lambda faults come back with my CE light.
Many thanks guys, saved me at least £200 squid.

[dazthephot]

This is the link i found, i used digital camera sensor cleaner and a cotton bud.

http://www.louv.tv/cars/m5/MAF/

[dazthephot]

well, as a continuation. the ce light is back on and my peake tool says its lambda related, so i guess i'll just swap the 2 probes.

anyone recommend suitable non oem replacements the stealer wants £140 each!

on the upside my maf clean is still working.