Kind of stumped need alittle help

[devinshaw3]

Im not sure if this is the right section but yesterday while i was driving my check engine light came on and the rpm's dropped. i let off the gas and pulled over and the idle was alittle screwed up tell i put it in neutral then it idle correctly so i put it back in drive and tried to drive again. it ran okay tell the turbo tried to boost alittle then it cut out again so i pulled over and read the check engine light. it came up with 22 and 45. 22 is a knock sensor that i just replaced a week ago and 45 is the pressure duty solenoid. I tried calling oriellys they said they have no clue what im talking about i tried calling subaru of spokane and they didnt help me much eathier. Anybody have any clue what im talking about or whats going on? by the way its a 92 legacy awd turbo automatic.

[free5ty1e]

I've had similar issues in my '92 and '94 before, and it always turns out to be that somehow a vaccuum line came off somewhere (reference the following ridiculously handy and well-used diagram provided by vrg3 countless times in the past):

http://surrealmirage.com/vrg3/vacuum/ej22t_vacuum.png

Do you have a boost gauge? Has your spool-up been ludicrously quick lately? Or perhaps spool has been normal but your car just won't let you get into boost?

A vaccuum / boost line has most likely come loose or off completely somewhere in there; the result is either that the turbo's wastegate is unable to see the pressure the turbo is generating, thereby keeping the turbo spooling to max at all times (you are probably running 20+ PSI of superheated plasma at this point) -- or perhaps the boost control solenoid or pressure exchange solenoid (both in that little cluster by your airbox) is not seeing the boost, which confuses the ECU as it sees the airflow from the MAF sensor.

Either way, the ECU would cut fuel in these situations, and you'd experience the situation you described (I believe).

Hope this helps!

[devinshaw3]

Thank you very much! im going to go threw my vacuum lines now because from reading that i have a feeling u had the same problem. Ill let ya know! thanks again made my day to wake up and read that haha

[devinshaw3]

oh and no i do not have a boost gage yet. I am waiting for my buddys to come on in the mail so he will take his off his car lol

[Legacy777]

If you find it's just a vacuum line issue, I'd suggest clearing the stored codes from your ECU so that in the future if you have a problem you don't confuse previous issues with what's going on now.

[devinshaw3]

Do u think this could kick a knock sensor? Or a knock sensor could go bad within like 2 weeks?

[free5ty1e]

Hmm I'd imagine not, especially if you got the newer white-wire knock sensor (the older original factory ones were actually recalled at one point for false knock readings in certain situations, IIRC) - those are supposed to be pretty solid. I've done this replacement for my '92 and my '94 and it was pretty much install and forget about it for me. I haven't had any issues in that area; so it wasn't a vaccuum line issue? That's unfortunate, it's always nice to find a simple fix for your problems.

I wonder if it'd be worth pulling the new knock sensor just to see if the sensor tip has any kind of residue or deposit on it; might be a clue. I'm stumped too now

Edit: and it might be worth clearing your Check Engine codes just to see if the knock sensor code comes back. Clues, clues, clues.

[devinshaw3]

You where right! it was just a hose that was off. thank you so much! that was a very helpful diagram. im going to replace my vaccuum hoses now that i have that diagram. Such a simple fix that i stressed so hard over haha

[free5ty1e]

Sweet, gotta love finding a simple fix -- glad you got it!

I've been there more than a couple times myself and each time I could swear all the hoses were fine until I finally got in there real close with some good light and traced them all.