Afm Problems - How Often Have You Had Them

[Scooby]

Guys;

Just wondering what your experiences are re AFMs failing. 6 months ago one of my original (I assume) 92 ones failed and I replaced both with some 94 ones (from a mate but it still cost me $200). Just had another one fail. There's another $350 thanks. That's ridiculous and I'm really unimpressed, my RS Liberty has 285k on the clock and no problems from the AFM, I don't know of another car type ie Skyline that seems to have so many problems with what shoud be a robust item - the forums seem littered with examples but no mention of what trhe life expectancy has been.

Regards

Edited August 15, 2005 by Scooby

[sav man]

I need new AFM's, and i'm not keen on paying $800 for new ones, or getting 2nd hand ones. I'm thinking of getting 2 new Nismo AFM's, and a PFC. I read on here that GTR's and MAP sensors are a real pain for a road car.

[Beer Baron]

i personally don't know of any GTR owner that has had an AFM fail. I know quite a few GTR owners too!

I know of plenty who have upgraded to nismo/RB20/VG30 AFMS but not because their RB26 ones failed.

[Sydneykid]

Guys;

Just wondering what your experiences are re AFMs failing. 6 months ago one of my original (I assume) 92 ones failed and I replaced both with some 94 ones (from a mate but it still cost me $200). Just had another one fail. There's another $350 thanks.  That's ridiculous and I'm really unimpressed, my RS Liberty has 285k on the clock and no problems from the AFM, I don't know of another car type ie Skyline that seems to have so many problems with what shoud be a robust item - the forums seem littered with examples but no mention of what trhe life expectancy has been.

Regards

<{POST_SNAPBACK}>

Please define "FAIL"?

An AFM is simply a hot wire that changes voltage due to airflow, no moving parts to wear out. A postive voltage supply and an earth (to heat up the wire) and a sensor wire back to the ECU. Not a lot to "FAIL" in there.

Are you sure they are not just dirty?

Like the Beer Baron, I also have never had an AFM fail, as in stop working, go open circuit, pass zero voltage. I HAVE seen plenty that are filthy from over oiled PODS and that makes the voltages variable. I have also seen a few very dirty ones due to zero air filters or screens. I have even seen one smashed to pieces by engine vibration after it was solidly mounted.

If you truly have a failed AFM, then I would be looking for the real cause, things like a short circuit, faulty wiring, over voltage alternator, excessive vibration, oil, dirt etc Becuase there is very little chance that the AFM is itself the cause of the problem.

cheers

[Scooby]

Thanks guys, this is good news...and bad. SK re FAIL I mean car running fine then occassionally jerk/stall/run OK/jerk stall etc. Fault codes show AFM. Examination reveals it has had some physical grief (but was previously running fine as stated). Tried cleaning with contact cleaner down the bore onto the element but to no avail (running stock airbox anyway). Replace with another one in A1 condition and all OK. 6 months later same thing, fault code shows AFM.

I agree there's not a lot to go wrong - that's why it peeves me.

It might be the connections I guess, do you know where I can source some aftermarket plugs to splice into the loom?

Thanks

Edited August 15, 2005 by Scooby

[sigsputnik]

my mechanic said the circuit board inside the afm can crack - this happened to mine.

[BH_SLO32]

Scooby,

I managed to kill an AFM on an RB20DET several years ago because I used silicon to seal the unit as I didn't have the standard O'ring. Apparently the vapours from the silicon will play havoc with electronics. In my case the AFM gradually failed. It started with the occasional hicup and finally wouldn't let me rev past 2000rpm (went into limp home mode).

It is for this that there are a variety of 'Sensor Safe' sealants on the market.

Some food for thought.

Cheers

[Scooby]

my mechanic said the circuit board inside the afm can crack - this happened to mine.

<{POST_SNAPBACK}>

that's the second time i've heard this, apparently there is a NZ company that repairs them. looking into it now.

[sigsputnik]

would like to know if it's true so i can get my old one repaired.

my gf would also like to know as the old one is sitting in the kitchen.

[sav man]

Thanks guys, this is good news...and bad. SK re FAIL I mean car running fine then occassionally jerk/stall/run OK/jerk stall etc. Fault codes show AFM. Examination reveals it has had some physical grief (but was previously running fine as stated). Tried cleaning with contact cleaner down the bore onto the element but to no avail (running stock airbox anyway). Replace with another one in A1 condition and all OK. 6 months later same thing, fault code shows AFM.

I agree there's not a lot to go wrong - that's why it peeves me. 

It might be the connections I guess, do you know where I can source some aftermarket plugs to splice into the loom?

Thanks

<{POST_SNAPBACK}>

That's the same as what mines doing (but i'm still on my first AFM)

Edited August 15, 2005 by sav man

[MountainRunner]

My top AFM did the same thing, was going intermittent. It was the circuit card having cracked so all I did was put in some jumper wires, easy job. Thats was 2 years ago. Its the only fault I have had.

[GTR32]

looks like they are fixable then...like your approach Mtn Runner. Advan reckon they'd go through 30 in the space of a year but then they get a lot of cars there.

[Sydneykid]

Advan reckon they'd go through 30 in the space of a year but then they get a lot of cars there.

Pardon me for being suspicious, but don't they make money from selling/fitting AFM's?

cheers

[siksII]

i think mine reads too high, is this possible?

the car runs quite rich (r33gtst) with the powerfc showing 99% injector duty cycle i run 10psi, and have fmic and exhaust.

at 6600 in second gear the AFM reaches 5115mv (maxxes out)

and from time to time the car stalls instead of dropping back to idle, or the idle fluctuates between nearly 0 and 1000rpm.

i have assumed this is the AFM does that sound right?

Edited August 16, 2005 by siksII

[GTR32]

Pardon me for being suspicious, but don't they make money from selling/fitting AFM's?

cheers 

<{POST_SNAPBACK}>

i see your point sk but my experience is that he charges what nissan charges plus freight. anyway how much money would he make by replacing perfectly good afms including .5 hr labour? $40? if he does 30/yr thats a whole $1200 before tax. i don't think they're the type of operation that sees overservicing by $40/time etc as the way to a great super fund otherwise they'd go broke. i guess he could get the more well heeled customers to pay for new afms and then recycle the used ones through the customers that couldn't afford new ones. but i just can't see that path leading to riches either...

obviously i respect the experiences of yourself and others, and i am equally suspicious of aftermarket outlets, but the forums seem to provide plenty of evidence that afm failure (accounting for those that are just dirty etc) is not uncommon. for example look at Mtn Runner who jumpered the busted board and made good - the broken board theory seems to gel with what i've heard elsewhere.

maybe it just seems as though skylines have more AFM problems than most but i thought i'd ask.

tell you what, i'll send you the one they reckon is stuffed and you can try it on a racecar. if it doesn't leave you stranded mid race you can have it.

[predator]

That's ridiculous and I'm really unimpressed, my RS Liberty has 285k on the clock and no problems from the AFM

lol, my mate has a liberty also, he had no end of problems recently with his air flow meter after installing an oiled pod (silly boy)

i'm for the "AFMS are as durable as any other electronics item on a skyline" (inc those coil packs!).. I suspect voltage or other wiring problems.. A voltage spike problem may consistently destroy AFM's I guess.

I woudln't say its just a nissan "problem".. most other cars can have faults tracked down to dodgy AFM's (when they do go wrong - I'm not saying they never do)

[GTR32]

hi pred;

yes i was warned very early about oily pods on a wrx and what they do...just lucky i guess. not sure if you are being sarcastic (feel free) re durability of electronics on skylines but they seem to have issues with igniters, coil packs and afms quite regularly unlike a lot of jap cars. as for the voltage spike harming it the afm is, as i understand it, a passive sensor ie it receives a set 12v feed for the element and there's not really a means of overloading it as it just sends a voltage sig to the ecu.

it's almost inevitable that other brands have afm problems but it just seems skylines have...more...and then there's the igniters and coil packs.

guys flame at will if you think differently but please make sure that whatever brand vehicle you're comparing against has had more than just 'your mates' incidence of failures.

sometimes it seems like gtr electrics = xr6t diffs and gearboxes.

might be time to start a 'report that e failure' thread like gtr geoff's 'report that engine failure' one.

cheers

Edited August 16, 2005 by GTR32

[blur]

that's the second time i've heard this, apparently there is a NZ company that repairs them. looking into it now.

<{POST_SNAPBACK}>

ive replaced a rb20 style afm cause it was logging codes, had a faulty circuit board, swapped it with a known good one and all was fine.

[siksII]

i swapped mine with another rb25 one i wasnt sure if it was good, it reads the same as my original, and the idle fluctuations are the same.

another good friend had idling(hunting) problems with his r33 gtr when he got it, they showed errors when connected to a consult interface. he changed them to r34 gtr(newer) afms and has not had a single problem since.

so my point is assuming they are clean(i know my friends were!) afms can definetly stuff up.

problem is knowing if it is stuffed, and finding a good second hand one if u cant afford new (new are very expensive!)

Edited August 16, 2005 by siksII

[predator]

yes i was warned very early about oily pods on a wrx and what they do...just lucky i guess. not sure if you are being sarcastic (feel free) re durability of electronics on skylines but they seem to have issues with igniters, coil packs and afms quite regularly unlike a lot of jap cars.

I think you'll find "any" car 10 years old or thereabouts may start to experience some electrical failures.. or have more liklihood of them occuring simply because of age and a hot engine bay.

Wasn't actually being sarcastic. Thing is, you always hear about the problems on here, as people, obviously post when they have a problem. But when all is fine, they don't.

Just from my own experiences, I owned my R33 for about 2 years (with all sorts of electronics extras tacked on), R32 for about 8 months now, and no electrical problems. Before that i've had R31 for about 4 years (similar system in some ways - ECCS).. and again no major electrical problems.

Its possible that GTR's may be more prone to some failures because they are running 2 afm's, higher power, and things are a little more squashed in (prone to heat?), but I've never owned a GTR so can't really comment.