Opel Zafira 1.8 200018XE grey import - MIL on, holding back, lacks powerArchived Message
Posted by Alan Potter on August 29, 2006, 1:15 am
The cars MIL light keeps coming on and the car has been back to Vauxhall 3 times (I think they are just switching out the light). The customer has not noticed any problems when driving but I can feel it holding back (lean miss fire)at high revs under acceleration. The car is also pinking. The fault code is for the Lambda sensor but I have checked it and it is switching perfectly. The MAF however peaks at 3.8 volts and the o2 then drops to 0.2 volts instead of increasing. a shot of carb cleaner makes it jump to 0.9 I also checked the fuel pressure which is ok at 3.8 bar and air leaks - none. no comms with autodiagnos vauxhall soft ware, however got in to eobd and found LTFT at 14%
Autodata says the Siemens MAF should be 4 (I thought a normal MAF reading was around 4.7?) therefore is 3.8 low enough to cause the symptoms and get this fault code?
I was also getting an odd effect when scoping both the maf and the o2 together. when the o2 went high the maf voltage was dropping to zero. Is this an o2 sensor with a floating earth,I had both leads earthed on the battery is that where i was going wrong I was starting to think there was something wrong with the scope, going back to this job on in a couple of days. any advice appreciated Thanks Alan.