# Symptom's of a faulty afm?



## Vips (May 13, 2007)

Have been having some problems since the heavy rain.  

Once my car heats up, it will randomly stutter and start sounding very rough. Once this begins to happen, the car doesn't want to rev above 2500rpm, randomly stalls near idle, and idles higher as though its gone into limp mode. This does sometime does disappear, and the car feels like its normal, allowing me to reach full boost with no holdbacks. 

I have checked all the boost pipes and they are all in good condition and tight.

It seems I can only think of it being the afm's playing up.

Can anyone tell me the symptom's of a faulty afm? 
Do these progressively die or pack up altogether?
How can I test the afm's to see if they are working correctly?
I've cleaned theses with carb cleaner, anything else I could clean them with?
How do I know how much life there's left in second hand afm's?

If anyone has any other ideas of what this may be, feel free to suggest other things I can check.


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## g_torphins (Jul 20, 2005)

Hey Vips

Sounds all to like AFMs to me.

The symtoms can kick in at any time.Especially interesting whilst trying to overtake slowish moving vehicles then having to crawl past keeping below 2500RPM 

I'd just get another secondhand set.
Swap one out at a time then you could indentify the one that's roached.
Hopefully leaving you with a spare for the next time.


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## Vips (May 13, 2007)

I know what you mean about interesting... Each time I need to pull out from a junction or at a roundabout it can get quite interesting... especially when people are pointing 'there's a Skyline!' :chuckle: 

Going to check the connections on each afm, as it turns out with a little searching I found that the solder may have dried or even cracked causing intermittent connections.

First problem with the Skyline, and its been driving me mad! :chairshot


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## Demon Dave (Sep 15, 2002)

*could well be AFM's*

one of my AFM's went a few months back. Similar symptoms: engine ran fine until it got warm, then it would struggle to idle properly, stall and just not run "right". 

Took it to Nissan who plugged it into their diagnostic machine and it reported the voltage on one of them was out.


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## rasonline (Mar 24, 2005)

Faulty AFMs can be a bloody freaking pain in the a$$... symptoms can be intermittent. Plus everything else will show up fine, and you won't have an idea of what is wrong. AFM can visually appear to be fine, but still be faulty.

Good luck fixing it mate. Hope it is the AFMs causing your probs and you can get it sorted.


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## MartinC (Jan 1, 2006)

code 12 stored in the ecu???


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## WillRobDon (Jul 29, 2006)

GTROC shop allows you to hire a set to test if yours are tits. £7 and you can keep them up to two weeks, awesome idea!!


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## G18RST (Dec 23, 2006)

My idle is sometimes just over 1000 rpm, like 1100ppm does this seem right ?


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## Vips (May 13, 2007)

The problems fixed!

Took apart the AFM's last night, and it turned out to be dry solder on the connections. Re-soldered all of them and the car runs like a dream, hasn't missed a beat!

Fixing Your Rb26 Afm's - Skylines Australia


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## Panzerdan (Apr 26, 2014)

I had similar problems. I've resoldering the points and had my first trouble free drive since forever. 

However if I unplug each maf it still stalls :-s


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