Afm Voltage Fluctuation, Q45 W/rb25det

[Rezlo]

Im noticing my voltage from the AFM tends to move around a lot, not like noise, say for instance im doing 80kph in 4th and the voltage is 2.200v on my PFC hand controler, if I keep the car 100% steady i see the value jumps semi erraticaly up and down by about .2v. Ive also noticed this AFM seems to be maxing a bit fast, I had a Z32 on previously and it ran fine up to 1.2 to 1.3bar with my GT30/40 but the Q45 at 1.4bar is up at 5V already,

Ive cleaned it, cleaned the filter, checked for leaks, all that is good, got a feeling it could be a dud AFM, is this a comon way they fail or start going bad? I did notice its got a little bit of a darker round mark on the actual sensor tab bit, not sure if its like that from new or if maybe my sensor has seen better days, any feed back would be awsome.

Many thanks

[Adriano]

Sounds like compressor surge

[Spook's_Skyline]

afms can definately be faulty

i just had to replace my standard afm as it would give a 0 volt signal randomly causing the car to stall;hesitate

graphing the afm, the graph would drop vertically when it started playing up

would just do that intermittantly to which made it hard to diagnose

[sinistaGTR]

how close is it too your tubro, we had massive problems with mine then we made a longer intake pipe and it worked a dream

[Rezlo]

Its not surge, does it even more at lower voltages, particualy around 2 to 3V,

Intake pipe is pretty long, see attached pics,

I think i must get a spare afm and take this one apart and check for dry joints, everything else seems to be perfect.

Ive got a video of the afm voltage moving around but its in this nokia format, will post it when I figure out how to convert it, also when displaying it as a graph it actualy forms a thick line because its bouncing up and down,

thinking of putting a tiny 0.1UF Cap in there to try smooth it out a bit, maybe a second ground off the ground wire right near the maf to the body to help keep it grounded correctly as well.

[Guilt-Toy]

the Q45 afm actualy has a less resolution then the z32. just because they are bigger in size it does not mean the resolution is better as well. The Z32 will handle more flow before maxing out compared to the Q45.

Looks to me that your AFM is too close to the turbo. as a test go to a hardware store and buy some PVC piping and plumb the AFM more deeper down into the gaurd and make sure the AFM is not directly infront of air flow. Block off the air duct if it is. (trust me on this one it will make it worse)

It may stop if you move the AFM further down the line. Try it. i had heaps of issues with my car but now it drives better then a stocker.

PS: Make sure the AFM is not in a position to fall down. They aint cheap to replace when you run over them =)

[Rezlo]

Pulled the maf cover off, checked for dry solders, apeared fine, gave it another clean although it was already spotless, then pulled the wiring apart, some how in my mega well wrapped up loom i managed to get some moisture in there, i pulled it right back and made sure the maf wires were wrapped, where they were joined i cafully put silicon inside heat shrink and shrunk it down to make a perfectly dry seal.

End result, car drives better than it ever has before, it must have been effecting the ground because the voltage is lower than it was and is 100times more stable.

thanks for info guys, glad it was a cheap fix, ordered a spare maf just incase.