Hey guys, Yesterday I got around to replacing my front brakes and that led to me driving it around for more than 10  minutes. After the car had gotten warmed up it started to idle low, about 400rpm. I drove it home and when I parked it was idling very low, it looked like it was at zero on the tachometer but it didn't die. I looked under the hood for about 5 minutes with the car on looking for any vacuum lines that maybe came loose or something but didn't see anything out of the ordinary. Any ideas on what my issue could be? Would replacing spark plugs and wires help any?

The idle air controller handles rpm at idle. Over time, gunk builds up and interferes with proper operation. You can clean it by putting a capful of Berryman's in the valve an let it sit for 8 minutes. Engine must be off when adding. Expect a longer start initially

 I do this annually and have never had idle issues.

Edited September 12, 20169 yr by MR_Loyale

The idle air controller handles rpm at idle. Over time, gunk builds up and interferes with proper operation. You can clean it by putting a capful of Berryman's in the valve an let it sit for 8 minutes. Engine must be off when adding. Expect a longer start initially

 I do this annually and have never had idle issues.

Is this the same on carbureted engines? And will this solution work on a carbureted engine?

Is this the same on carbureted engines? And will this solution work on a carbureted engine?

 

Mine is spfi. Not sure if the carb version has an iac.

Was the low idle occurring before your recent work?  Is this wagon (85 ...a great year) new to you? This doesn't sound like plugs and wires to me but does sound like a vacuum line or maybe a cap falling off of a vacuum line.  I had that happen once to me.  It was a factory cap (in front of carburetor but toward the passenger side) which I must have bumped off or it slid off.  They age and the rubber gets tired, ...same for the hoses.  Anyway, I did a lot of normal maintenance and tuneup work, still had the problem, very low-choppy idle and running very crappy.  Searching around and about to give up I saw the missing cap, and put my finger over the tube.  Presto, the engine came back to life.  Then I had to go back and set the tuning back to stock settings because I was trying to correct the issue with timing, idle speed screw, etc.  Good luck, and hope you find it is simple.

It was idling low (about 400rpm) before but the last couple of days its been about 200rpm when warm and wont stay on at all until its warmed up (choke works fine, but now that I think about it I can start the car without engaging the clutch not sure if thats relevant or not) It will stay on at 200rpm its just really rough.

The wagon is new to me (been through nine different owners as far as I can tell) but the guy who sold it to me said he replaced most of the vacuum lines under the hood, which made the idle better (should have asked him what he meant by that) I checked the lines again this morning but couldnt find any cracked lines or cracked/worn rubber caps, and none missing as far as I can tell. Replacing my front brake rotors and pads was the only work I did recently but I didn't open the hood at all during.

Maybe make sure they all go where they are suppsed to?

Tyler, the most important point here is that the wagon is new to you.  These cars were engineered to run fine without a lot of tinkering and to be easily worked on (especially the routine maintenance) by the owners with basic tools.  Once they are set to factory specifications and in good operation they run and run and run usually until the owner messes with something, breaks something, or a part needs changing.  In your part of the country there are shops who know these cars well and maybe specialize in Subarus, I know in Denver and suburbs there are.  Look around, ask locals, find a shop that knows these older Subarus. I recommend you 1) Take or get your car into one of these shops and get the problem diagnosed and maybe fixed there.  Get the wagon running decently with the help from a mechanic or a knowledgeable local USMB guru.  2) Find online and download or find online and buy yourself a hard copy set of factory service manuals (FSM) for 1985.  For 1985 there are actually seven volumes/books but 1,2,3, are the main books and 4-7 are supplements and corrections to the first three books.  I'll add a link to 4-7 for sale now.  3) Start going through the manual's "routine maintenance schedule" for your wagon.  You will learn about the car and get things in good repair.  Good luck.   https://www.amazon.com/Subaru-Service-Repair-Manual-FACTORY/dp/B0090PRCXE/ref=sr_1_fkmr0_2?ie=UTF8&qid=1473788276&sr=8-2-fkmr0&keywords=1985+subaru+wagon+factory+manual

Ahem. The owner of USMB does work on older Subies. If you are looking for a shop to fix it, you should give them a call.

 

http://retroroo.com

Edited September 13, 20169 yr by MR_Loyale

Ahem. The owner of USMB does work on older Subies. If you are looking for a shop to fix it, you should give them a call.

 

http://retroroo.com

Well, that would be the best and they won't waste your time or money.  If you get AAA with a 100 mile (free) tow like I have, the tow to the shop (if necessary) would be free.  Keep that wagon purring.

Alright, I went ahead and changed the spark plugs anyway, looked pretty new actually I was a little surprised. After that I checked my hoses for the third time and lo and behold I found a vacuum line just hanging with grease packed into one end. Heres a few pictures

The second picture is showing where the line was plugged in but I don't know where the other end of the hose is supposed to go, my vacuum line diagram on the hood is mostly gone, also what is said device where the vacuum line was plugged in?

I think it connects to the underside of the air filter  which is a bitch to get to without disconnecting other hoses to turn it enough to see. Got a camera? Take pics as you disconnect so you/ll know where to put hoses back . What happens if you just adjust the idle screw in to increase the idle speed?

Hey Tyler, I had a similar problem with mine a few years back.  Ended up being a loose oil fill cap.  Just throwing it out there.  Good luck!

The idle air controller handles rpm at idle. Over time, gunk builds up and interferes with proper operation. You can clean it by putting a capful of Berryman's in the valve an let it sit for 8 minutes. Engine must be off when adding. Expect a longer start initially

 I do this annually and have never had idle issues.

Where is this located?