Newbie needs help with fault codes!

[afish01]

I'm new to working on cars, so about all I've learned about working on Subarus is by reading posts on this board and trying to figure out what you guys are talking about.

I have a '92 legacy ej22t MT, and I managed to check my own engine error codes using the method listed on this site. Even after clearing the memory by disconnecting the ECU fuse, I'm still getting two error codes: 22 and 24, which are the air control valve and the knock sensor. However, when I drive around, I do not see a check engine light.

So first off, are these two things likely to affect engine performance very much if they really are failing? I don't have alot of money to buy new parts, so I need to know what the cheapest option is.

Secondly, if I can fix/replace these things cheaply myself, how the heck do I find them on my car? I'm not familiar enough with cars yet to immediately locate things like the knock sensor and air control valve, so if anyone can post pics of either of these, I would really appreciate it.

Thanks for your help!

Adam

[afish01]

BTW, the car does have some rough idling problems even after it's wamrm, and during hard acceleration there is sometimes a temporary loss of power that comes and goes. I'd like to know if these problems are related to my two error codes.

Thanks,
Adam

[tris91ricer]

Probably are related, yes. The temporary loss of power, and the erratic idle are directly related to the codes you got, knock sensor and air control, respectively.
The knock sensor sends a signal to the ECU when it detects knock, which makes it pull timing, IIRC. Don't quote me, I'm not 100% sure, the knock sensor isn't my forte.
The erratic Idle, though, would be anything air or fuel related, and since you've got an air error code, we'll assume that's the broken part.
The knock sensor isn't too hard to replace, from what I understand, but it sounds like you're a little hesistant to dig into your car by yourself. Find a competant friend to help you, and the process gets much easier.

Keep us posted.

[gnuman]

BTW, the car does have some rough idling problems even after it's wamrm, and during hard acceleration there is sometimes a temporary loss of power that comes and goes. I'd like to know if these problems are related to my two error codes.

Thanks,
Adam

the power loss is related to the knock sensor. This is located under the intake, just to the drivers side of the Throtle Body (that metal box the four metal tubes come from). It looks like a (usually) black circle with a single wire coming out of it, and a 12mm bolt in the center. you need a 12mm socket and at least a 6" extension to get at it without having to remove the intake manifold. Josh (Legacy777) will probably chime in here soon enough with pictures of both parts (I'll bet that guy has a picture of each and every part on a Subaru engine. . . ) The knock sensor is fairly easy and cheap to replace. Not as sure on the Air Valve. . .

[BAC5.2]

The power loss that comes and goes is from the IAC valve.

That's fuel cut. The car bucks and jerks when you lose power, doesn't it?

The knock sensor pulls timing, which makes the car bog horribly. It only does this when there is an active knock code.

If there is an IAC code stored in the ECU, Fuel Cut is gonna happen. It's based on TPS, RPM, and Vehicle speed (I believe those three), and if the three are out of sync (i.e. WOT at low RPM at high speed), then 3 seconds and BAM fuel cut. Then 3 seconds, BAM fuel cut.

The IAC is a bitch to replace, and is really easy to get to when the turbo is removed from the car. If the turbo is out, then it's the easiest thing in the world. 4 8mm bolts, a wiring harness, and a hose and your done.

Problem, the IAC valve for the turbo car costs almost $500 from the dealer.

Good news, I've got a brand new one that I'll sell you for less money.

FWIW, when I was having IAC problems, my idle was really really shitty and the car would sometimes stall out when I would be coasting in neutral.

[dzx]

Is the IAC Denso?

[BAC5.2]

Is mine?

It will work on your car

[Legacy777]

here's pics of lots of stuff

http://www.main.experiencetherave.com:8 ... /injectors

knock sensor
http://www.main.experiencetherave.com:8 ... P_2481.JPG

[afish01]

So basically, unless I take off the turbo and fork out a few hundred dollars, the IAC is not going to be easy to fix? I heard somewhere that you could take it apart, clean it to free the stuck parts, and then reinstall it. Is this true or even possible?

Thanks for the help with everything, though. That pictures link is really helpful.

Adam

[afish01]

BTW, BAC5.2--how much are you selling your IAC for?

[Legacy777]

the coolant temp sensor on the turbos is actually on the other side.....or at least it is on the motor I have sitting in my garage.

[Tleg93]

So basically, unless I take off the turbo and fork out a few hundred dollars, the IAC is not going to be easy to fix? I heard somewhere that you could take it apart, clean it to free the stuck parts, and then reinstall it. Is this true or even possible?

Thanks for the help with everything, though. That pictures link is really helpful.

Adam

Yes, you can clean a sticky IAC valve. Search the bbs, it's here. If you need help searching, set it for all words and pick the category(s) instead of just searching everything.

[dzx]

I think i'll try this too just because it couldnt hurt. Unless i broke something in the process....

[BAC5.2]

When I cleaned my original bad IAC, it began to stick open, and the car would idle at 2k RPM's. Better than stalling entirely, but a pain all the same. Just a warning.

Afish01 - I'll take $250 shipped for it. I paid over 400 at the dealer, and it's only got about 100 miles on it or so.