steveo3002
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ok thank you....earth the meter on the car or the sensor ground ? or doesnt matter ?
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It doesn't matter for taking a signal reading but you need to confirm you have a sensor ground so take your reading between sensor signal and sensor ground first. If you don't get a reading then you can measure between sensor signal and battery -ve to see if you have a bad sensor ground.
steveo3002
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ok cheers will see if i can get a look at the weekend
steveo3002
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just a thought...if its a frazzled ecu or rat chewed the wires somewhere causing this bogus reading , wont it still read the same with my meter
the only way i could get a different reading is if its my scanner getting it wrong ?
the only way i could get a different reading is if its my scanner getting it wrong ?
ECU or scanner, yes, or a bad ground to the ecu if you get a bad reading with the sensor ground and a good reading to battery -ve. Or signal wire fault if you get a bad reading with the signal wire plugged in and a good reading with it unplugged, etc, etc....
IMO it's important to build up a picture of what you have and don't have to determine the next step.
MetalMonkey
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To me that trace doesn't look all that bad? that spike also registers on the pre-cat, possibly a misfire? 0.1v indicates a very lean mixture though.
It isn't unknown for a new sensor to be faulty or even a batch of them. But I don't think that is the case here.
First thing I would check is the exhaust for any leaks in the system, cracked welds on the cat, loose bolts on the exhaust manifold etc to be sure there isn't any air getting in before the cat. I'd also check again while driving and see what the voltage is, it may run very lean at idle.
Another thing you could do is take the airbox off and squirt something down the intake to enrichen the mixture, like non chlorinated carb cleaner or easy start, propane etc - just to make the mixture rich, you should see the ECU trim back the fuel to compensate and it should register on the pre and post cat sensors, which would suggest it is all working.
All this has to be done when the cat is up to temp.
It isn't unknown for a new sensor to be faulty or even a batch of them. But I don't think that is the case here.
First thing I would check is the exhaust for any leaks in the system, cracked welds on the cat, loose bolts on the exhaust manifold etc to be sure there isn't any air getting in before the cat. I'd also check again while driving and see what the voltage is, it may run very lean at idle.
Another thing you could do is take the airbox off and squirt something down the intake to enrichen the mixture, like non chlorinated carb cleaner or easy start, propane etc - just to make the mixture rich, you should see the ECU trim back the fuel to compensate and it should register on the pre and post cat sensors, which would suggest it is all working.
All this has to be done when the cat is up to temp.
steveo3002
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yeah i was planning to spray some carb cleaner in to see if sensor 2 respsonds
assuming the .1v isnt what it wants to see to keep the light off
assuming the .1v isnt what it wants to see to keep the light off
steveo3002
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right , thought i ought to update things
went in for a mot and it passed , but now the cat is rattling like a good un , so needs to come off anyway lol
light still comes on , havent been at with the meter yet , i guess its fit for another year anyway
went in for a mot and it passed , but now the cat is rattling like a good un , so needs to come off anyway lol
light still comes on , havent been at with the meter yet , i guess its fit for another year anyway
