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Vauxhall Zafira-B Z19DT 8V 2011 - No throttle response from standstill, code P2279 #

Posted by Shaun Dale on February 5, 2015, 5:54 pm

Year of Manufacture *: 2011
Engine Size and Code *: Z19DT 8-Valve
( Optional ) Scanner Used: Tech 2
( Optional) Fault Codes: P2279

The vehicle has little or no response to the throttle pedal when pulling away, once it has moved off power then picks up and it drives normally.
The car is an auto and pulling out of junctions can be a nightmare.
The P2279 code "Intake air system leak detected" led me to smoke test the intake and a split hose was found and replaced. No improvement.
The EGR was removed and found to be jammed open with carbon. As I couldn't clean it sufficiently well a new genuine one was fitted.
The MAP sensor was dirty and was cleaned.
The MAF appears to correlate with expected values but a MAF reset was performed anyway.
When driving the P2279 does not return but as the DPF is about 60% loaded I attempted a forced regen it failed and the P2279 code is logged again.DPF back pressure (from memory) was about 8kPa at a steady 60mph.
Something I have not addressed yet is that the engine runs excessively cool, about 60deg C and I suspect the thermostat, I can't see how this would affect throttle response though.
APP values are as expected and I also checked the UEC for water ingress/damage.
The car was originally a Motability car and also a Cat-D with damage repairs to front nearside, to cap it all it was bought for use as a private hire car!
Perhaps I'm missing something simple.
Shaun.

Re: Vauxhall Zafira-B No throttle response from standstill

Posted by Mark Carter <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT1428' width='330' height='300' border=0 style='border:none;'> on February 5, 2015, 6:34 pm, in reply to "Vauxhall Zafira-B No throttle response from standstill"
Mark Carter

Desired over actual boost plus air mass ?

Modern cars, Its all wizardry and witchcraft

Re: Vauxhall Zafira-B No throttle response from standstill

Posted by Shaun Dale on February 5, 2015, 7:21 pm, in reply to "Re: Vauxhall Zafira-B No throttle response from standstill"
Edited by board administrator February 6, 2015, 2:59 pm

Expected and actual airmass correlate fairly well, boost is a little low, but at tickover there wouldn't be any boost anyway and that's where it won't pick up. It just doesn't seem to add any fuel. I'm not sure if it's possible to graph values on Tech 2 as I'm not particularly familiar with it as it's borrowed.
Shaun

Re: Vauxhall Zafira-B No throttle response from standstill

Posted by andrew pethig <iframe src='https://members.boardhost.com/ukautotalk8/info/user=ukat3731' width='330' height='300' border=0 style='border:none;'> on February 5, 2015, 7:24 pm, in reply to "Vauxhall Zafira-B No throttle response from standstill"
Andrew Pethig

changed the diesel filter ?

does it rev up nicely when its in netural ?

have you scanned the gear box for codes?, has the box got enough fluid in it ?

8 kpa is only 1 psi so thats not where your problem is.

i think the p2279 is a red herring.

has the app got a dead spot in it that the scan tool can not see because its too slow ?

Re: Vauxhall Zafira-B No throttle response from standstill

Posted by Shaun Dale <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT2719' width='330' height='300' border=0 style='border:none;'> on February 6, 2015, 8:58 am, in reply to "Re: Vauxhall Zafira-B No throttle response from standstill"
Shaun Dale

I always preach "You can't go wrong by changing the fuel filter" on a Diesel but in this case it is not short of power at WOT so I haven't done one yet.
No, it revs poorly in neutral as well.
I think the DPF is OK too.
I agree with the red herring.
The App seems good and most systems seem paranoid about track 1/track 2 plausibility. So I would expect a code to be flagged.
Both gearbox and ABS have been checked to see if a torque reduction is being requested but both appear OK, no fault codes certainly.
It has just come to mind that the vehicle has recently had a gearbox replacement, I will check with the customer to see if there is any apparent relationship between the two events.
I intend to scope fuel pressure actual/demanded and injection duration when I get on it later.
It just seems like the accelerator demand is being rejected.
Shaun.

Re: Vauxhall Zafira-B No throttle response from standstill

Posted by Shaun Dale <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT2719' width='330' height='300' border=0 style='border:none;'> on February 6, 2015, 11:42 am, in reply to "Re: Vauxhall Zafira-B No throttle response from standstill"
Shaun Dale

Update on this one.
I took the air hose off the throttle body and there appeared to be excessive EGR being returned even with the EGR solenoid unplugged.When some throttle is applied the gas flow is a massive.
I strongly suspect a blocked exhaust, possibly the catalyst. I'll get it next door onto the ramp later and have a look.
As it's a taxi and "We need the car" is the ruling they have applied I suspect it's been driven for ages with the engine light on and due to the split intake hose and jammed open EGR the exhaust is now all sooted up.
Shaun.

Fixed: Vauxhall Zafira-B No throttle response from standstill

Posted by Shaun Dale <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT2719' width='330' height='300' border=0 style='border:none;'> on February 11, 2015, 10:48 am, in reply to "Re: Vauxhall Zafira-B No throttle response from standstill"
Shaun Dale

We took off the first catalyst and found it to be blocked with soot.
I had already fitted a new EGR valve which it blocked with carbon on a road test.
Final remedy was to clean out the catalyst, clean the new EGR and refit, replace the split turbo hose and of course replace the thermostat so the engine got hot enough to do a natural regen, which it did on a motorway roadtest.
Thermostat failure on these is quite common apparently but of course combined with an airleak and a faulty EGR making excess soot and the low temperature preventing DPF regeneration from happening it was bound to end in tears.
Shaun.

Re: Fixed: Vauxhall Zafira-B No throttle response from standstill

Posted by andrew pethig <iframe src='https://members.boardhost.com/ukautotalk8/info/user=ukat3731' width='330' height='300' border=0 style='border:none;'> on February 11, 2015, 11:41 am, in reply to "Fixed: Vauxhall Zafira-B No throttle response from standstill"

how did you clean out the CAT ?

i usually bin them.

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