code 12 i've replaced afm re-earthed can anyone help with tracking the loom??

SIR GTIR

Member
Hey everyone
currantly running a Z32 afm i've replaced the afm and the fault returned
it seems i have the same problem as craigcarlon has, while the engine was out i've replaced the coolant temp sensor
(tho i doubt this could be and any thing to do with the fault as the terminal had broke off and the engine ran fine before)

anyway I'm seriously considering running a new loom to the afm since it runs fine for a white Drove to work 20km/12miles run fine 8hrs later jumped in and tryed to drive home bearly got 5km/3miles
tryed to clear the code on the road side just kept coming back by the time i got towed back home it started and run fine again

i dont know if its related but on my greddy infometer i'm getting only 12.9 and briefly less tho when you probe the battery and the alternator i get 14.4 volts

sorry about the long post But better to have the whole picture isnt it ?
thanks in advance
Paul
 

Fusion Ed

Active Member
re-earthing afm does not help. All the sensor earths end up on the throttle body earth points, and shouldn't have an others added as it can cause earth loops/noise. Anyhow, perhaps try another ecu, I've seen them get damaged when things are removed and put back.

Its normal to see some voltage drop the battery. The GTi-R doesn't have great wiring for the charge circuit. That can be improved if you wish by running a new wire from the alternator to the battery directly. Also worth re-doing the earth strap at the same time. However neither of these will give the AFM error. Best thing to do is unplug the AFM and test the pins there back to the ECU. IF that is all as it should be and you can move all wires about with no change then could be a faulty maf.
 

SIR GTIR

Member
awesome Thanks ed to the 2 earths that bolt up at the pletuim chamber? as i did move them from there to the underside of the pletuim thought they came back from the injectors

i had wondered if there was a earth failing round the ecu and some how its all strangely connected If im on the right track above i'll shift them back

what values do i need at the afm pins ed ??
 
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All ecu earths originate from those two earth points. They merge near the ecu plug ish.
Ah I see, that's pretty crap though you'd have thought they would bring in all sensor inputs as differential pairs... the amount of noise I was seeing when using my Ion sensing project was quite bad. Still, nevermind was just curious....sorry for hijacking your thread mate haha.
 

Fusion Ed

Active Member
Noise on car looms is terrible. Its surprising they work at all sometimes.

Sir Gtir, You should have 12v gnd and signal. The ground should be pretty much zero resistance to ground. (go to the bolts on the engine manifold.) then using a diagram find the other end of the two wires at the ecu end, and check resitance across those from the engine bay to the ecu. Resistance should again be tiny. An ohm or so at most.
 
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