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Vauxhall Corsa 1.2 Z12XEP 2006 - Hunting at idle - Unresolved #

Posted by Paul edge on September 29, 2016, 3:46 pm

Year of Manufacture *: 2006
Engine Size and Code *: 1200 z12xep
( Optional ) Scanner Used: Kts and vaux com

Hi All

Hunting at idle. Fine when revved.no fault codes.timing checked all OK. Compression check all 210 psi. Fuel pressure good.

Manifold vacuum on tick over only 10 inhg.

Connected mityvac to map senso, live data alters when vacuum applied 20 inhg = 1.85 volts (within spec.)

smoked tested inlet no leaks..

Any pointers to what to test next

Paul

Re: Vauxhall Corsa 1.2 Z12XEP 2006 - Hunting at idle #

Posted by andy pethig on September 30, 2016, 5:19 pm, in reply to "Vauxhall Corsa 1.2 Z12XEP 2006 - Hunting at idle #"
Andrew Pethig

low engine vacuum can also be caused by restricted exhaust, also late valve timing, are you sure that the timing chain has not streched??

have you checked if there is vacuum present in the crank case put your vacuum gauge in place of the dip stick.

what are your fuel trims at idle ??

Re: Vauxhall Corsa 1.2 Z12XEP 2006 - Hunting at idle #

Posted by Paul edge on October 2, 2016, 1:17 pm, in reply to "Re: Vauxhall Corsa 1.2 Z12XEP 2006 - Hunting at idle #"
Paul Edge

Have pegged crank and put bar across cams all lined up.
Will check vacuum tomorrow and trims

Re: Vauxhall Corsa 1.2 Z12XEP 2006 - Hunting at idle #

Posted by aidan birley on October 2, 2016, 1:40 pm, in reply to "Re: Vauxhall Corsa 1.2 Z12XEP 2006 - Hunting at idle #"
Aidan Birley

Hi
agree restricted exhaust / cat next check

Also check brake servo, may be masked by one way valve when smoke testing.

Aidan

Re: Vauxhall Corsa 1.2 Z12XEP 2006 - Hunting at idle #

Posted by Paul edge on October 3, 2016, 9:18 am, in reply to "Re: Vauxhall Corsa 1.2 Z12XEP 2006 - Hunting at idle #"

Removed front o2 sensor..car still the same..
Stft. idle -1.8 <>2.3
Ltft. idle 0.0
Stft.1500 rpm -3.0 <>7.0
Stft. 2500 rpm -12.2 <>-3.0

Re: Vauxhall Corsa 1.2 Z12XEP 2006 - Hunting at idle #

Posted by Paul edge on October 5, 2016, 10:58 am, in reply to "Re: Vauxhall Corsa 1.2 Z12XEP 2006 - Hunting at idle #"
Paul Edge

No vacuum in crankcase

Re: Vauxhall Corsa 1.2 Z12XEP 2006 - Hunting at idle #

Posted by andy pethig on October 5, 2016, 6:19 pm, in reply to "Vauxhall Corsa 1.2 Z12XEP 2006 - Hunting at idle #"

evap purge stuck open, or egr slightly open , they have a habit of getting little balls of carbon that hold them open. this will nick your vacuum and make the car run a little rich , (if its a map engine) ,

you can see the position on a scan tool, it should be closed at idle

Re: Vauxhall Corsa 1.2 Z12XEP 2006 - Hunting at idle #

Posted by Paul edge on October 6, 2016, 7:51 pm, in reply to "Re: Vauxhall Corsa 1.2 Z12XEP 2006 - Hunting at idle #"

Egr fully working and reading on diagnostics kit..removed from car incase it had a burnt valve.but all OK...evaporation valve pipe disconnected and blanked off..servo pipe disconnected and blanked off...it is a map set up.

Think I have found something see pic
Waiting for new manifold to arrive
Paul

Re: Vauxhall Corsa 1.2 Z12XEP 2006 - Hunting at idle #

Posted by Tony Ludford on October 7, 2016, 7:16 am, in reply to "Re: Vauxhall Corsa 1.2 Z12XEP 2006 - Hunting at idle #"
Tony Ludford

Looks nasty, have you ordered an injector too?

Re: Vauxhall Corsa 1.2 Z12XEP 2006 - Hunting at idle #

Posted by Paul edge on October 7, 2016, 9:06 am, in reply to "Re: Vauxhall Corsa 1.2 Z12XEP 2006 - Hunting at idle #"
Paul Edge

Customers has supplied a 2nd hand manifold with injectors
Paul

Re: Vauxhall Corsa 1.2 Z12XEP 2006 - Hunting at idle #

Posted by Paul edge on October 8, 2016, 8:31 am, in reply to "Re: Vauxhall Corsa 1.2 Z12XEP 2006 - Hunting at idle #"

Well.manifold fitted.car still the same.damm
Have also done a cylinder leak tester. All OK.
Paul

Re: Vauxhall Corsa 1.2 Z12XEP 2006 - Hunting at idle #

Posted by andy pethig on October 8, 2016, 7:48 pm, in reply to "Re: Vauxhall Corsa 1.2 Z12XEP 2006 - Hunting at idle #"
Andrew Pethig

how much of the timing chain tensioner can you see sticking out,

on a nissan any thing over 10mm means the chain has stretched .

we did a nissan chain last week with the tensioner showing 18mm and all the timing marks lined up.

this was hunting on idle and no codes,

if you don't have too much money in it, just time there no shame in giving it back not fixed, give up and move on life too short.

Unresolved #

Posted by Paul edge on November 1, 2016, 10:42 am, in reply to "Re: Vauxhall Corsa 1.2 Z12XEP 2006 - Hunting at idle #"
Edited by board administrator November 3, 2016, 1:53 pm

Customer decided not to proceed any further with this fault.

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