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Vauxhall Corsa 1.2 X12XE 1999 - Bad flat spot (waveform) - Fixed #

Posted by Shane Gray on October 3, 2013, 5:33 pm

Year of Manufacture *: 1999
Engine Size and Code *: 1.2 x12xe
( Optional ) Scanner Used: Vaux com

Hi,
Had this one in as it is hesitating.
Fault code for lambda sensor and in live data it is showing lambda voltage dropping to 0 and staying there, so i fitted new o2 sensor and its still the same.
I have checked cat and exhaust for blockage.
Checked fuel pressure and hold pressure all ok.
Checked valve timing all ok.
I have scoped the coil pack and on idle the pattern will drop out every now and then is this correct?
I have uploaded pattern.
Any help please?
Shane

Re: Vaux/Corsa bad Flat spot

Posted by Kevin Apps <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT2589' width='330' height='300' border=0 style='border:none;'> on October 3, 2013, 6:01 pm, in reply to "Vaux/Corsa bad Flat spot"
Kevin Apps

Shane

"Fault code for lambda sensor and in live data it is showing lambda voltage dropping to 0 and staying there"

So what was the code ? It will almost certainly refer to lambda circuit and not directly to the sensor.
Fuel pressure OK what was it ?

Kev.

Re: Vaux/Corsa bad Flat spot

Posted by Chris Angus <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT5111' width='330' height='300' border=0 style='border:none;'> on October 3, 2013, 6:04 pm, in reply to "Vaux/Corsa bad Flat spot"

Sounds like the MAF, have you scoped it to check the output at WOT?

Re: Vaux/Corsa bad Flat spot

Posted by Tony Bickers <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT5143' width='330' height='300' border=0 style='border:none;'> on October 3, 2013, 6:08 pm, in reply to "Vaux/Corsa bad Flat spot"
Tony Bickers

Hi Shane,

I had one same age,same engine last week holding back and putting MIL on with a P0130(2)low voltage intermittent code for o2 sensor , could not fault the o2 sensor but MAF was reading low on WOT, a second hand MAF unit transformed the car.Why it was throwing o2 sensor code I dont know,read with Vauxcom

Re: Vaux/Corsa bad Flat spot

Posted by Chris Angus <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT5111' width='330' height='300' border=0 style='border:none;'> on October 3, 2013, 6:13 pm, in reply to "Re: Vaux/Corsa bad Flat spot"

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It's not telling you the o2 sensor is faulty, just that it's not happy with the signal it's receiving, most commonly down to a fuelling issue.

Re: Vaux/Corsa bad Flat spot

Posted by John Ritchie <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT2638' width='330' height='300' border=0 style='border:none;'> on October 3, 2013, 7:23 pm, in reply to "Re: Vaux/Corsa bad Flat spot"
John Ritchie

I would look at fuel pressure & Maf readings .Out of interest what are the fuel trim readings ?

Regards
John

Re: Vaux/Corsa bad Flat spot

Posted by Pete Mutlow <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1569' width='330' height='300' border=0 style='border:none;'> on October 3, 2013, 7:26 pm, in reply to "Re: Vaux/Corsa bad Flat spot"
Peter Mutlow

Hi Shane,

Agree with Chris. Scope MAF and report. Common problem.

Regards

Pete M

Re: Vaux/Corsa bad Flat spot

Posted by shane gray <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=ukat3442' width='330' height='300' border=0 style='border:none;'> on October 3, 2013, 9:10 pm, in reply to "Re: Vaux/Corsa bad Flat spot"
Shane Gray

Thanks guys.
Kev pressure is 45psi on crank and then drops to 40psi and holds.
Did think about maf but thought these wont start if faulty, suppose did has a diffrent fault

.
Will scope tomorrow with o2 sensor.
Let you no how I get on.
Shane

Re: Vaux/Corsa bad Flat spot

Posted by Pete Mutlow <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1569' width='330' height='300' border=0 style='border:none;'> on October 3, 2013, 11:48 pm, in reply to "Re: Vaux/Corsa bad Flat spot"
Peter Mutlow

Hi Shane,

*Did think about maf but thought these wont start if faulty* They do.... but can produce a bad flat spot!

Regards

Pete M

Re: Vaux/Corsa bad Flat spot

Posted by Kevin Apps <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT2589' width='330' height='300' border=0 style='border:none;'> on October 3, 2013, 11:50 pm, in reply to "Re: Vaux/Corsa bad Flat spot"
Kevin Apps

Shane
Are you going to let us know the fault code and it,s discription ?
Blindfold again !
Kev.

Fixed #

Posted by Shane Gray on October 4, 2013, 3:10 pm, in reply to "Re: Vaux/Corsa bad Flat spot"
Edited by board administrator October 5, 2013, 3:23 pm

Hi guy,s,
Been busy so didn't have time to scope o2 and maf.
So bit the bullet and fitted new bosch maf and it runs perfect now.
Sorry didn't post fault code but couldn't remember it

Funny how you over look the obvious some times

Shane

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