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Ecu Diagnostics - Afm Came Up Faulty

WazR32GTSt

By WazR32GTSt,
in Engines & Forced Induction

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WazR32GTSt Grand Master

WazR32GTSt

Posted
Posted

my first post described the initial problem i was having... http://www.skylinesaustralia.com/forums/in...howtopic=111605

so basically for no reason the car would almost stall (or actually stall) and then when it was re-started would idle about 2000rpm and then bounce between 1000 and 2000rpm... It sort of sounds like "limp-home mode"

then if i wait about 1-5min or if i shut it off and start it again soon, it would go back to normal.

I tried resetting the ECU and then cleaning my AFM yesterday, but the problem happened again today, so its not simply a 'dirty AFM'

BUT... this time it happened, i had my laptop (with nissan datacscan) with me! i plugged it in (but could not display the values for some reason?). i could, however, do a diagnostics test. It came up with AFM faulty

SO MY QUESTION IS THIS:

given people's ast experiences with AFMs, and that this problem seems to be intermittant rather than full time, is it likely to be

a) faulty AFM - has it happened before like this?

b) break in wire to AFM - thus ECU sees no signal

c) faulty ECU - somehow shorted the AFM circiut on the ecu board.. unlikely, as the problem is intermittant

And, if its the AFM unit itself, can i get a new one from nissan, and if so how much? or am i best to find a second hand one and hoping for a fully working unit?

I'm personally thinking its a dodgy solder in the AFM which has come loose, and causing it to intermittantly fail

i would really like some help here guys, as my car isn't driveable until this is fixed

cheers in advance,

Warren.

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https://www.sau.com.au/forums/topic/111844-ecu-diagnostics-afm-came-up-faulty/
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RedDrifter Experienced

RedDrifter

Posted
Posted

Dont bother buying a new one the old can be fix fairly easily and cheap.

Just get a nife and cut the top rubber seal out and remove the plastic cover.(Take your time as its a pain in the neck).

Then once the top is removed you will see a copper cover that is soldered onto the afm's circuit board box(also copper) Just desolder its join and take it out.

Now where the plug is you will see that it has 5 pins that go into a fork like peice of metal.

It is soldered to this and these joints tend to fail and require resoldering. Use a fine tipped soldering iron and resolder these joins. This fixes the afm probs 9 times out of ten.

Once done test it and if ok resilicon the top in and away you go.

I have done this to:-

my afm R32

My brothers AFM R32

My mates Subaru Liberties afm

And my mates 300xz afm and it has fixed them all.

If you know you afm is farked then give it ago as you will have nothing to loose.

Good luck and hope this helps.

RB30-POWER Mentor

RB30-POWER

Posted
Posted

As above possibly dry/cracked solder joints.

If the AFM circuit board looks ok. It can't hurt to check the wires for continuity as well to rule out potential breaks somewhere.

If all the above fails get a s/hand one off here from $50-$100 on average.

RedDrifter Experienced

RedDrifter

Posted
Posted
thanks heaps for your help guys

i only have moderate soldering experience, but want to give this a go tomorrow...

off to buy a fine-tipped soldering iron! (and some solder)

cheers,

Warren

Dicksmith or jaycar sell them for sfa.

You wont need an ultra fine tip just the common ones found at the above places.

When I get a chance I will put up a diy to fix an afm with pics and everything. Most likely after easter when I get my car back.

When/if u change to z32 afm you can actually use the same procedure to swap over the afm plugs so the Z32 plugs staright into you stock loom. Anyway enough of me rambleing on have fun and good luck.

WazR32GTSt Grand Master

WazR32GTSt

Posted
  • Author
Posted

ok i re-soldered it this afternon, plugged it back in, and it starts.. which is the first plus - that i didn't stuff anything else up

now to give it a test drive.. will post the results of how i go tomorrow

might also write a little "how-to" document as i took a couple of pics as i was going..

cheers,

Warren

  • 1 month later...

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