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Discussion Starter · #1 ·
i think my air flow meters have being playing up the last couple of days

i checked the values on the pfc and there is about a 0.4v diffrence between them both

is this normal?:nervous:
 

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I have the exact same thing with my nismo ones, i currently have a misfire off-boost on light throttle but am still unsure if the difference in AFM values is the cause or not...
 

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I noticed that my standard AFM's read differently with HKS filters, and I thought one was faulty.

So I upgraded to nismos because I was thinking for the future and they have the same difference (well slightly less because the relationship between airflow and voltage on the nismo's is different).

On boost the rear turbo AFM reads less than the front then on trailing throttle the difference reverses. I think it is down to the different shape and length of the path from filter to turbo inlet, which affects the flow distribution through the AFM housings.

Pete, I doubt it is the cause of your misfire as the PFC uses an average (sort of) of the two readings to calculate load. Have you tried cleaning the earthing points. Come to think of it my intermittent misfire has become less frequent since cleaning up a couple of the chassis earth points. As you have an R32 you could just run extra cable from the battery -ve terminal to the ignitor earth and a few extra to the chassis. This isn't easy on the R33 as the battery is in the flipping boot! :rolleyes:
 

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Doh!

There's 2 chassis earth connections at the off side front under where the oem boost solenoid sits. There's a further 2 earth's on the inlet manifold under where the oem FPR sits. There's the one on the ignitor and then the main chassis earth direct from the -ve battery terminal to chassis.

Also check fuel injector connectors as one coming loose has caused a misfire for me on the impreza previously.
 

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Discussion Starter · #10 ·
well i think i'v cracked it.took of the pipe's on the apexi boost controler and gave it a good squirt of carb cleaner

and it's been ok since:clap:
 
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