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Vauxhall Zafira Z18XE 2005 - Hesitation and brings up the MIL - Fixed#

Posted by Tim Watts on February 18, 2016, 7:11 pm

Year of Manufacture *: 05
Engine Size and Code *: z18xe
( Optional ) Scanner Used: Solus pro
( Optional) Fault Codes: p0170

Hi guys.
I have had this car come to me from another garage.
Every once in a while car hesitates and brings on MIL otherwise drives ok 120+k on clock.
All Exhaust readings good.(would fly MOT)
Coolant/air temp readings good.
Only code listed is P0170. This will clear but returns days later.
Both 02 sensors front and rear switch and react to additional air/fuel.
However short term F/T switches -5 to +7 but long term is frozen at 15.6 under any conditions.
Done thro testing for air leaks both on inlet and exhaust all to no major avail.
The oil is crap (service light on)and it was a litre over the max..
Maff sensor was showing low voltage across the range so replaced. The readings have improved but no improvement on fixed LT trim.
The breather inlet in throttle body was blocked solid. Good find I thought, cleared but not made the slightest difference..
Next thing I can think of is swapping out o2 sensors (if only to get a reaction) and testing for blocked exhaust, other than that it looks like having ECU tested.
Any thoughts would be appreciated..

Re: Vauxhall zafira

Posted by Andrew Pethig on February 18, 2016, 9:20 pm, in reply to "Vauxhall zafira"
Edited by board administrator February 22, 2016, 3:44 pm

do you have the ability to clear all fuel adaptations with the solus ?

also in eobd do the fuel trims match those in the vauxhall side ??

p0170 is a lean condition, so when faced with this i like to go on a test drive and graph the front o2 sensor and TPS , you can do this with the souls .

if the o2 voltage goes low when you floor it to the red line in second gear, then you know you do have a lean condition, if the voltage goes high, then you have a rich condition (as you should when you nail it).

use the TPS data PID to know when you nailed it.

have a look when p0170 sets for freeze frame data in EOBD or the vauxhall side to know what conditions set the code , you will find some valuable data in there.

For whats it worth, if the o2 voltage goes low on the test drive , FUEL PUMP, FUEL Filter, Injectors, Start with a fuel pressure gauge and go from there , Vauxhall supply a valve on the rail.

Happy hunting.

Re: Vauxhall zafira

Posted by Andyhyoung <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT5148' width='330' height='300' border=0 style='border:none;'> on February 18, 2016, 10:18 pm, in reply to "Vauxhall zafira"
Andrew Young

This may sound crazy,but have you tried disconnecting the battery?Doubt if anyone could perform an accurate test of the ecu.

Re: Vauxhall zafira

Posted by Tim Watts <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=ukat3942' width='330' height='300' border=0 style='border:none;'> on February 18, 2016, 10:53 pm, in reply to "Re: Vauxhall zafira"
Tim Watts

I suspect that P0170 is generic to a number of faults.
One of the first things was to check freeze frame. shows p0170 as long term fuel trim.(15.6 fixed) shows nothing else of much use. light load,, low rpm speed around 45kph and air and water temp norm. Nothing pending.
For some reason solus only gives fuel trims on GM in EOBD.
Tested fuel pressure KOEO 55 psi KOEO 52-54 psi
Also the car is auto, just makes gunning it that more awkward.
Might just try it on Delphi, sometimes that shows data not covered by solus.
The only suspect thing is, the external air temp sensor was reading -40c. last reading was -6c. had this of been IAT it would make sense but I can find no correlation to ECU on autodata wiring diagram. So I think it serves dash readout only which read +12c which was correct?
On early BMW it served dash read out and ecu

Regards

p.s have to wait for MIL to reset. Would help if I could repeat it on regular basis.
I suspect that the LT trim @ 15.6 is border line pid set

Re: Vauxhall zafira

No Andy it dos'nt sound daft at all.
The last thing I wanted to do before leaving to shoot myself was just that, however the owners have no radio codes.
Think I will just do it anyway and cock a deaf unn'

Re: Vauxhall zafira

Posted by Shane gray <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=ukat3442' width='330' height='300' border=0 style='border:none;'> on February 19, 2016, 3:29 pm, in reply to "Re: Vauxhall zafira"
Shane Gray

Hi,
Had one of thsee with same code and I traced it back to a split pipe on fuel sender in tank. Fuel pressure was fine but it would drop when left for few seconds.
Shane

Re: Vauxhall zafira

Posted by Matt Booth <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=ukat3028' width='330' height='300' border=0 style='border:none;'> on February 20, 2016, 1:33 am, in reply to "Re: Vauxhall zafira"
Matthew Booth

Its going back a few years, but I'm sure I had one of these that would only reset the lt ft when performing a throttle valve adaptation...

Matt

Fixed #

Posted by Tim Watts on February 23, 2016, 4:18 pm, in reply to "Re: Vauxhall zafira"
Edited by board administrator February 26, 2016, 7:53 am

Success, well sort of.
Customer took car away over weekend, MIL off and drove ok but little sluggish.
Phone call Monday morning non start.
Check out. MIl on and TCS on, no compression..
Engine bore washed and flooded.
Got it running and drove to garage.
No live to O2 heaters. Much searching and found lone fuse in relay box blown.
Cause was live feed to ECU signal wire in rear sensor shorting but only at mid to high temp and only for very short periods.
Re did throttle reset and delete stored emission data after battery disconnect.
Result LT fuel trim 0.0 ST switching -4 to +5 and both o2 sensors switching accordingly.
Car now drives good nothing pending on scanner.
Returned car for them to run till weekend then rescan prior to any invoicing, just for my own satisfaction..
Thanks for the input guys...

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