Subaru Forester Owners Forum banner

Stray grey female plug & vacuum tube? - smoke from passenger side? (merged thread)

1132 Views 14 Replies 7 Participants Last post by  RyanT
Stray grey female plug & vacuum tube? - smoke from passenger side? (merged thread)

PLEASE HELP: What does this grey two pronged sensor go to???

Car is a 1998 Forester DOHC 2.5 EJ25.

Reinstalled my engine and now reinstalling my intake manifold: there are exactly 10 connections on the intake manifold and I can tell where every one connects: but this grey female plug is stray. Perhaps it doesn’t plug into anything?

Fixed a blown head gasket, saved this car from going to the scrapyard. Trying to get it running today. Any and all help is appreciated.

Thank you!


Olympia, WA


See less See more
1 - 15 of 15 Posts
A few more details about exactly which model and year you have might generate more responses.
What year, engine... Add that to your sig in your user CP
Thank you, I thought I had included that, too stressed out from this project I guess.

Its a 1998 Forester DOHC 2.5 EJ25. (I believe this is the first Forester)

Have you tried starting the engine? Any CELs might give you a clue.
No, its not the knock sensor unfortunately (unless there are two separate connections -- I don't think this is the case).

That one I do have figured out and snapped in. Its a white to white connection.

Have you tried starting the engine? Any CELs might give you a clue.
Well, I don't have the intake manifold in yet, so I was going to try to figure this out before hand, but I'm going to go blow any sand out of the intake on the heads right now and start getting it in. I'll be monitoring this thread to see if anyone figures it out.

But yes, this is a good idea and I'm going to do this if I don't figure it out.

My friend thought perhaps it was an option for accessory? Like a heating block or something that my car doesn't have?
Good for you for DIY. Hope it all works out alright.

Did you replace the timing belt & pulleys while you were in there?
I did indeed replace the timing belt. Not the pulleys. I've done water pump replacement before but that was as intense as it got.

I'm hoping for the best, but I'm a pessimist so I think this thing probably only has a 50-50 shot of actually working so I didn't want to sink too much money into it. The pulleys all felt like the bearings were strong.
Make sure you can turn it over by hand before cracking the starteer.
Camshaft Position Sensor?

Also, have a look through this thread, might give you some clues
HELP! Suburu Forester 98, stray vacuum tube?

Working on a Suburu Forester 98, finally got the engine in and running!

Can anyone tell me where this stray vacuum tube plugs in? It's plugged into the intake manifold but don't know where it connects or even if it does.

I turned on the engine and only let it idle for 3 mins, then the smoke got more apparent (coming specifically from the passenger side of the exhaust) and I shut it down. Any ideas? Staying up late tonight to try to figure this out.


See less See more
@Conner Edwards no need to create a new thread, you already have an active thread on your engine project. Your threads have been merged & the thread title edited. :wink:


['07 FSXT MODding Journal] ['03 X MODding Journal]
Vacuum hose plugs into the cruise control.

Sent from my Pixel XL using Tapatalk
That loose 2 pin plug might be speedometer, reverse switch, or neutral switch.
1 - 15 of 15 Posts