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Fixing Your Rb26 Afm's


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This guide will show you how to repair one of the most common problems with the rb26 (and other) afms.

The problem most afms have is dry solder joints. This is where the solder joins on the plug it self dry up and crack. It can also be an intermittent fault, which makes it hard to diagnose the exact cause.

If your GTR won’t idle properly, and wont rev over 3000rpm, then either one or both of your afms are faulty.

Before doing this, make sure its your afms that are the problem.

Check the ecu for error codes, and borrow a set of known working afms to see if you afms are faulty.

Tools Needed:

Soldering iron


Sharp knife or other sharp object

Black Silicon

1. Remove the afm from your car, the pics show what it looks like.


2. Using a sharp knife, cut away the silicon. I found if you cut straight down on both side of the silicon, more comes out.


3. Once all the silicon is cleared, pry off the lid. It should easily come out.


4. The Following pics shows the joins that dry up and cause the problems. Resolder the joins using fresh

solder. Be careful not to hold the iron on for too long as the heat might damage the components inside.


5. To show you the severity of the dry joints, i removed the 4 bolts and easily pulled the whole plug out.

All 4 joints where completely loose!! Note that you don’t have to do this, just apply new solder over the

whole lot, the old solder will melt.


Also, do this at your own risk; if you cause any damage to anything or anyone by following these instructions, it’s your fault.


Check (if you live in usa): Kroger Weekly Ad, or Myer catalogue. Edited by PHATR32
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I had a problem with my afm a while back and did the same thing.....hasn't missed a beat since.

It was fine at idle, but when I went over bumps the afm would obviously get moved a bit and the car would start to jerk and carry on and then when the road smoothed out it would be fine.

I'm sure I mentioned it in a thread somewhere but as per my username was too lazy to do a DIY thread.

Nice work :bunny:

Edited by Lazy-Bastard
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  • 1 month later...

I fixed my hunting problems, thanks to the books at my local library... no wait this tute! I looked under the copper shield covering the circuitry to find dry joints and flux everywhere, cleaned it up and BAM, my hunting issues resolved!

- Dont attempt this unless you have some background in electronics... -

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  • 3 weeks later...

This is the same problem i had on my GTR. i thought it was internal AFM fault. i just cleaned them out when i took my turbos off and when put them back together i cleaned the connections and put a heat shield around the top AFM..

this thread is good idea as all GTRs seem to do this :happy:.

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wow great advice :D mine has been playing up a little in my R33gtst. I tried cleaning it out with elec contact cleaner but it made little difference. I've also tried the AAC valve and it still seems to want to play up a little at times (although cleaning the AAC has helped the car shedloads at 5-10mph speeds so I definitely recommend that bit of maintenance).

I'll give my AFM a shot and see how the connections are to the plug :D (might get a spare first tho eh hehe!)

SAU rules!




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yeah I've got a Z32 but I was told I wont really need one until I'm running higher boost - I might consider getting it fitted anyhow tho

AAC - Auxiliary Air Control valve ..theres a tutorial on this site on cleaning it out :thumbsup:

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  • 3 months later...
  • 3 months later...

good tute.

had prob with my afm when i dropped it by accident that it showed signs that something was wrong. before going straight to a change over, i tried this and found dry cracking of the contacts.

re-solder the contacts and bam! car good as new!

good post

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  • 4 months later...

Hey thank you very much, i actually fixed mine before readng this by trial and error with a lot of stuffing around and without removing the silicone, mine is not soldered together rather they just touching therefore working i go over bumps etc n it fine now, but i may do this in future to fix it.

I have a 33 gts and mine did not go over 2500rpm, and another question if i was to put a GTR AFM into my 33 would it upgrade its performance? Regard hame

could some one PM me the answer..

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  • 2 months later...

Can't thank you enough Steve. Almost had enough of it when the problem started, but got down to it in the end. Your tutorial really helped!

Over on the other side, I was told to simply replace them, and send the car in to somebody who knows what they're doing! But I saw this tut and thought I would have a go, and presto!

Thanks again!

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Hey people, one of my AFMs just died last week. Started with intermittant rough running and stalling that would restart fine run ok for a few minutes then run rough again etc etc.

Turned out the signal return pin was the one with the dry joint and would not resolder until I cleaned it up.

AFM works fine now but I'll need to tidy up my power FC map now as the car was tuned with the dry joint which would be causing the voltages to be compromised. Something for other people to consider too......



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  • 2 months later...

its pretty much exactly the same for the rb20det. just did it today. when I took the cover off there was almost no solder holding the contacts in place, which explains why it would run good sometimes and shitty other times. thanks for the tutorial. saves me and the guys up here in the states alot of cash as parts for the rb engine are harder to come by up here, and not everyone wants/can upgrade to z32 mafs. Thanks again

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  • 3 weeks later...
  • 4 weeks later...


I have a few questions and please excuse the fact that I am so newby to all this...

1. After step 3... do I apply solder lead on that joints or what do I do... I don't understand?

2. Also, how do I reseal everything?

If you or anyone else can provide additional pictures, this would be much appreciated.

Edited by Spunky Munky
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  • 3 weeks later...

Hey guys this is a great tute, especially for people with some skills for doing this. It fixed my problem of car cutting out and stalling. Thumbs up to people on here for sharing their wealth of knowledge :(

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