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Vauxhall Astra 1.7 DTi 2002 - Fluctuating air mass sensor #

Posted by George Ambelas on February 2, 2013, 8:45 pm

Year of Manufacture *: 2002
Engine Size and Code *: 1.7dti
( Optional ) Scanner Used: superscan

hi everyone this is from my own car which drives well and has no fault codes i am just a bit conserned with the air mass output which flaxtuates on idle between 1.4-2.0v the flactuation is there if i hold it steady at higher rev's as well. if i snap the pedal down it will peak at over 4v like i said it runs well and the idle is generaly steady but sometimes the revs will momentarily jump up about 50 revs
has anybody seen this?

Re: astra flaxctuating air mass sensor

Posted by Kevin Apps <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT2589' width='330' height='300' border=0 style='border:none;'> on February 2, 2013, 9:17 pm, in reply to "astra flaxctuating air mass sensor"
Kevin Apps

George.

What does it look like if you scope the MAF.

Kev.

Re: astra flaxctuating air mass sensor

Posted by James Eardley <iframe src='https://members.boardhost.com/ukautotalk8/info/user=ukat3143' width='330' height='300' border=0 style='border:none;'> on February 3, 2013, 6:19 pm, in reply to "Re: astra flaxctuating air mass sensor"
James Eardley

Hi George

Kevin is right, of you scope it all will become clear.
The refresh rate on the scan tool is simply not fast enough to display what is actually happening......

Although its having a good go

James

Re: astra flaxctuating air mass sensor

Posted by keith brown <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT1429' width='330' height='300' border=0 style='border:none;'> on February 4, 2013, 4:58 pm, in reply to "Re: astra flaxctuating air mass sensor"
Keith Brown

I totally agree with both replies & use scope first however there must be a fault with oyur dec ,although in panel mode its generally slow ie "not live data" its usally more dampend than your pic

Re: astra flaxctuating air mass sensor

Posted by george ambelas <iframe src='https://members.boardhost.com/ukautotalk8/info/user=ukat3245' width='330' height='300' border=0 style='border:none;'> on February 4, 2013, 8:22 pm, in reply to "astra flaxctuating air mass sensor"

thanks for your comments i will scope it as soon as time permits me and report back. as for the superscan it's graghing is very good and compares well with the my scope. i have graghed many air mass sensors and i have never seen one flactuating like this.

Re: astra flaxctuating air mass sensor

Posted by george ambelas <iframe src='https://members.boardhost.com/ukautotalk8/info/user=ukat3245' width='330' height='300' border=0 style='border:none;'> on February 9, 2013, 2:12 pm, in reply to "Re: astra flaxctuating air mass sensor"

hi chaps here it is i have scoped it with hot engine and on idle and it's exactly the same as the gragh, flactuating between 1.10v-2.10v as i said no faults it drives well it's just that i have never seen anything like it. has anybody got an explanation

Re: astra flaxctuating air mass sensor

Posted by Craig Hewison <iframe src='https://members.boardhost.com/ukautotalk8/info/user=ukat3409' width='330' height='300' border=0 style='border:none;'> on February 10, 2013, 12:40 pm, in reply to "Re: astra flaxctuating air mass sensor"

Bad earth?

Craig

Re: astra flaxctuating air mass sensor

Posted by aidan birley <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT2879' width='330' height='300' border=0 style='border:none;'> on February 10, 2013, 1:36 pm, in reply to "Re: astra flaxctuating air mass sensor"
Aidan Birley

hi

Not sure of your time base, but could it be reflecting EGR ?

Try scoping against EGR

Cheers Aidan

Re: astra flaxctuating air mass sensor

Posted by george ambelas <iframe src='https://members.boardhost.com/ukautotalk8/info/user=ukat3245' width='330' height='300' border=0 style='border:none;'> on February 10, 2013, 5:45 pm, in reply to "Re: astra flaxctuating air mass sensor"
George Ambelas

hi aidan thats an interesting idea and i will test it as soon as posible

Re: astra flaxctuating air mass sensor

Posted by george ambelas <iframe src='https://members.boardhost.com/ukautotalk8/info/user=ukat3245' width='330' height='300' border=0 style='border:none;'> on February 11, 2013, 4:30 pm, in reply to "Re: astra flaxctuating air mass sensor"
George Ambelas

i had a bit of time today and had a look at the air mass at 2800 rpm when the egr is't pulced and it's still flaxtuating althow a little less
the next step is to try another ams or remove the egr valve and have a look at it

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