I've had a few posts here before and I've done a few things to the car since buying (some have definitely improved things) it but I still feel certain something isn't 100%. For one I can not get the fuel consumption to go under 10L/100. And it feels gutless a lot of the time.
It's a 2005 Zafira manual. According to redbook.com.au the fuel consumption should be:
Fuel Urban (l/100km) 9.0
Fuel Extra Urban (l/100km) 6.8
Fuel Combined (l/100km) 9.5
Parkers.co.uk: 33mpg = 8.56L/100
The 9.5L/100 figure is what is quoted in the Holden brochure material. As said I'm consistently above these figures. I've been generally filling up with E10 unleaded but have tried both 95 and 98 octane with little difference. What I've done so far:
Replaced cam and balancer chains
Blanked off EGR
Installed K&N panel filter
Replaced coolant temperature sensor
I've had the exhaust off and there was no pre-cat fitted.
Installed reconditioned injectors
Cleaned throttle body
The car runs well from take off until I start pushing the accelerator further in. Then it becomes all growl and little action until the rev counter gets close to 4000rpm and it starts pulling better. I find I'm generally better off holding back on the throttle until the revs pick up to that value as it seems to bog down more if I floor it. Classic signs of wrong fuel air mixture aren't they? If it was having compression issues I wouldn't expect it to pull off so well on low revs...?
It seems that a new coil pack can solve performance issues on many Z22SE's but are there any give-away symptoms for this? The revs occasionally wander a little on idle, maybe +/- 50rpm? But there are no obvious misfires as far as I can tell.
Could it be fuel pressure?
Airflow sensor?
Lambda sensors?
Air leaks in the inlet? How reliable is the connection of the EGR hose to the inlet? I've just left the valve in place, swung to the side on the blanking plate.
There are no fault codes. Hope someone can shed some light on what I should try next!
Thanks, Kristian