Shadow's GT-L, 5MT trouble codes

[ShadowGT]

Things have been happy in happy subaru town for me. Lots of love and lots of playing outside like a good wagon should.
My commute to work is 36 miles total. Last few trips home with hundreds of yards left until it's time to park, my RPM's shoot up above 2200 RPM and float up to 3000 RPM on it's own. I creep in first gear clutching in to get parked and shut off.
That happened twice but only on the way home, never to work.
Today in my home spot it happens again with the idle at 3000 RPM on it's own as I'm nursing the clutch to bump me in my stall.

I let it sit an watched.. it started to increases a bit more and I got worried, I turned off the AC, I pumped the gas pedal and that's when the CEL came on and the engine starting bucking horribly. I just killed the motor right then and there.
I checked the CEL with my ScanMaster, it reads one code a P1507. Simple I've been working the past twenty hours and I'm delirious research tells me that this code means the car is idling excessively high and the car will try to cut fuel, hence the bucking incident.

I have a new IACM. Actually it's a cross between two of them. The valve body with a broken solenoid, a good solenoid to a broken valve. I swapped the parts over and the car has run great for months until now.

It's always after a long spirited drive with a long slow down process when I get the code. All hoses are in place, everything looks normal to me.

Strange side notes while I'm still focused:
My clutch pedal makes a groaning / sqeuaky sound when it's pressed in. Don't know what that's about.

My gas warning (You Dummy Light )comes on with well above a quarter tank and then goes away.
Don't know what that's about.

Sorry I'm rambling, I just pulled a huge shift and I already took some sleep meds but I wanted to type this in before I crashed out.
Thanks and sorry in advance for my shit typing and meandering.

Moral of the story.. P1507 with a good IACM an good hoses, good filters.
Thanks!

[chuckthefuk]

1a) Clean you IACV or IACM. They get gunked up and tend to stay open or closed. Its just a little stepper motor.
1b) It could be your neutral switch --> http://forums.nasioc.com/forums/showthr ... ?t=1196685 (http://forums.nasioc.com/forums/showthread.php?t=1196685)
2) The squeaky noise that you hear is your throw-out bearing. Example my car only makes noise with the clutch pushed. My friends outback only makes noise when the clutch is not pushed at all. Solution open your transmission and replace it. Not cheap :-(
3) Your contacts on your sending unit in the trunk (in tank sending unit/fuel pump) may be dirty or corroded

Hope this helped
-Chuck

[ShadowGT]

Thanks for the information. By the way, those NASOIC guys in that thread are confusing. Seems like a bunch of them are describing different problems except the IACV cut off. One guy goes as far as blaming the dashboard cluster. But there are some interesting leads when you sort it out.

I'm going to pull the IACV off and look at it. I just put that in not too long ago but I've put a lot of miles on since then.
A quick glance this afternoon confirms I still have good vacuum hoses and nothing is out of place.

I'll probably get that neutral switch too, seems like that's one of the last sensors I haven't replaced yet.

By the way, I'm never posting under the influence of ambien after a long shift again.
I don't know why I mentioned that clutch pedal squeak. Its the actual pedal, the sound is coming out right there at the pedal hinge thing. Considering the clutch is relatively new, I'm not too concerned.

Hey btw, assuming that the low fuel warning light is correct, how much gas is left in the tank? This is not something I want to unintentionally discover.

[chuckthefuk]

drugs are bad mmmmmkay :-p

a little pit of grease will fix the squeak

The fuel thing is a little confusing depending on year and parts used. Usually if the light goes on you have almost a quarter tank left. That being said my last GTs light only came on just before I ran out of gas. Good rule of thumb is the light turns on you got a 100km left.

But again the only way you'll know is drive drive drive and carry a jerry can with you. Then its all dash clicks from there :-D

Good luck
-Chuck

[ouch1011]

Where is your IAC sitting as far as its adjustment? In the middle? Far clockwise or counter-clockwise?

I don't know what that code is for, but I know that when the PCM detects an IAC problem or determines it is no longer able to control engine RPM, it will stop using the IAC and cut-off fuel injectors and retard the ignition timing to bring the engine speed down, which creates a misfire/shaking engine feeling.

[ShadowGT]

I lined up the IAC to be centered with the assembly body after I figured out how it operates.

For what its worth, what you described is exactly what that code means, IAC cut off.

Freaking autozone told me the neutral safety switch costs a hundred bucks. Need to look elsewhere.

[Grafton]

find a 5mt in a junk yard, neutral safety switch is the farthest one back on the drivers side, tbh the reverse switch has the same plug, threads, connection, and tip you *might* be able to use one of those in a pinch...

[ShadowGT]

I haven't even started looking for that neutral safety switch.. I haven't had time. Tell you this.. no salvage yard in south east Texas is going to have a Subaru-anything. I've been through that before a few times.

I pulled the IACV off. The valve body was really nasty but the valve turned freely without resistance. I cleaned anyway but I noticed something.

The magnetic motor thing. Technically it works. I hooked my voltmeter to it as the Haynes manual instructs and found that 1,2 and 2,3 have 9.3 and 9.6 ohms. The manual says 9. I figured this is close enough.
There is power going to the harness from the car.

What gets me is that when I pulled the motor from the valve, it's all corroded inside and there was a ton of magnetic shavings all over the valve axis post.
The rubberband gasket between the motor and valve was broken up too. This thing really went to shit over the past few months.

Putting the motor back on the valve causes the valve automatically of center. If I close or open the valve by hand and slip the motor back on, it just slips back to a partially open (or closed if you're a pessimist)
I sort of haphazardly hooked everything back up to see if putting some voltage from the car through the motor will line up the valve.
That didn't work. Something happened to that magnetic lining. Even if I mounted and slightly rotated the motor it's not enough to be completely closed or completely open.

So.. 300 for a new one..
or 70 for a used one with shipping included. I went with the used one.