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-   -   Missing / Flat on boost .. (http://www.perth-wrx.com/vb/general-subaru-discussion/22717-missing-flat-boost.html)

RichX 23-01-2009 09:52 AM

AFM has been removed and cleaned, but haven't cleaned the coilpacks and AFM connector. That's all on my list this weekend.

Where is the idle valve and how do i pull it out and clean it?

Indeed it is a process of elimination .. Murphies Law its always the last thing you do, or perhaps i'm just shortsighting something or making it more complicated than it needs to be!

Cheers for the support in my times of desperation ;) - The car has been awesome up until this issue came about.

Kato 23-01-2009 09:54 AM

Have you tried anyone elses AFM yet?

Strubaru 23-01-2009 09:55 AM

on my99 it is the circular bit with the plug on it on top of the throttle body, not sure about bugeye but probly in the smae sort of area

of course its going to be the last thing you do, why would you keep trying after its fixed LOL :D

RichX 23-01-2009 10:04 AM

I take it you mean "A"

Coilpacks are different on MY01+ too, they are directly on the plugs.

Edit got it:

A - Idle Air Control solenoid valve and gasket directly on top of main chamber (2 screws)
B - MAP sensor located on the top left (2 screws)
C - Throttle Position Sensor located low on the driver’s side (2 screws)
D - Coolant line attached to driver’s side with spring-loaded hose clamp
E - Coolant line attached to bottom side with spring-loaded hose clamp
F - Throttle body to intercooler hose (2 hose clamps)
G - Gasket between throttle body and intake manifold

[img]http://www.stage-infinity.com/wp-content/uploads/2008/04/tb-assembly-labeled.jpg[/img]

Strubaru 23-01-2009 10:06 AM

yep, thats the one, i took mine off and cleaned it out with carby cleaner, i also cleaned the plug with contact cleaner, mine had a bit of calcification on the plug where water had dribbled down there from waterspray nozzles on my tmic

RichX 23-01-2009 10:50 AM

[size=2]Funny you should mention that !! Look at this ..[/size]

[size=2]Gonna pull that off and inspect also as that could be the fault perhaps.[/size]
[size=2][/size]
[size=2]Problem developed a few months after the waterspray went in.

[img]http://members.ii.net/~rismith/TPS/TPS%20001.jpg[/img]

[img]http://members.ii.net/~rismith/TPS/TPS%20002.jpg[/img][/size]

Rossco 23-01-2009 05:11 PM

Just a FYI: all those throttle body plugs are sealed with a 3 or 4 lip silicone seal inside the plug (ie they're waterproof).

Richy: mate if I had time to rip the scan tool out of my car again (hard wired now) I'd let you use it for as long as needed.

Do the earth thing....... See if it helps.

coil packs don't all fail at once (not a cause of the stall issue)
Idle speed stepper motor rarely fails (if it did it will stop in the fully open position = high 2000 rpm-ish idle)
your tps is within the normal range (from our previous logs)
Map sensor would throw a permanent code.

AFM WILL cause idle issues (usually high-low-high idle speed cycling (hunting)) but that is usually apparent in 99-00 gc8's with their failure mode of a fixed output voltage regardless of actual airflow (they lock to a 30-40% limp mode, also known as boost-boom!! mode for the unwary).

BUT...So will a bad earth as the ecu tries to respond to fluctuating sensor (map,afm,tps, coolant temp) outputs caused by fluctuating reference voltages due to bad/poor earth return (engine block -> battery)

Also note: the car may feel strong if the afm is sending the mixture lean now (if it's failing) lean = max grunt = boom! be careful!

RUSSGT 23-01-2009 05:15 PM

Yeah man no WOT after it stalls. Thats just silly!

RichX 23-01-2009 05:21 PM

Sean has confirmed the AFR's are alright .. The only thing which really confirms at this point that the AFM is at fault is the two codes above, which have not returned, even after the stalling issue.

I am honestly on the verge of giving up if it's not fixed after the additional earthing. What avenues do i have left other than pulling the motor to pieces.

Oh and yeah it stumbled on the way home while on boost as well and still no codes. I am at the end of my options just about. If the earthing doesn't do it i'm just gonna have to throw money at it until it hit the right spot.

Rossco 23-01-2009 07:11 PM

[QUOTE=RichX]Sean has confirmed the AFR's are alright .. .[/QUOTE]

Did it fault for him?

The stumble could be it going lean intermittantly.

Intermittent faults are the hardest to diagnose.....

The tune could be rich as fuck and safe.........

but and here's the big BUT!: when the AFM faults and decides to send incorrect data to the ECU telling the ECU there is no air flow when there actually is massive airflow (i.e at 4500 rpm on boost) it will go lean regardless of other sensor inputs or the tune.

It may only do this occasionally if the AFM brain farts aren't happening all the time, which it seems yours aren't.
So your car may be running safe rich mixtures 99% of the time....it's that 1% you have to worry about.

And don't give up...That only leads to Holden ownership :p


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