Hello All,

 

New to this forum. Relatively new to subis and am a relatively new DIY "mechanic"

 

My 93 legacy is idling bad. Runs down highways fine. Will idle enough to keep engine running until fans kick on then its just to much and she stalls. I have read a lot of similar stuff on here but I'm still stuck. I have checked and cleaned the IAC and replaced gasket. Got the code (35 i believe) for the canister purge solenoid and replaced it. Upon replacing the later idle became a little worse maybe more pronounced. Currently have no CEL codes coming on. I'm fairly convinced it could be a vacuum leak or poor gasket somewhere. I "checked" around with the propane bottle but didn't get any spikes in the idle. I really want to know how I can check the vacuum system but don't know how.

 

Any help would be very much appreciated.

hello again.

 

Did some looking on you tube and found a guy who said you could check for vacuum leaks using a cigar. I tried it out and found a lot of smoke coming out from underneath the intake manifold. Looking at the chilton manual there doesn't appear to be any gaskets under there just the right and the left sides where it attaches. Maybe that trick doesn't even work. Is air supposed to come out somewhere under there? Even just blowing on the hose you can hear a good amount of air coming out on the drivers side half of the intake manifold.

 

I notice that it sounds like a lot of air is being sucked in somewhere when it's running

 

Just trying to get someone to bite on this if they have had anything similar or any other ideas.

 

I'm tempted to take off the intake manifold or at least some stuff around it to get a better look to see if I can see more smoke coming out

K I might reveal how stupid I am here but since you're waiting so long for a response here goes.

 

Do you think you may have a valve leaking? Making your PCV system work overtime?

I wonder if a bad valve leak ends up throwing off your air/fuel mixture because the extra air input after the MAF sensor would not be calculated by the computer. (I GUESS not realized by the computer at least until the O2 sensor crys foul)

 

need a compression test to find out for sure...

Edited March 25, 201214 yr by glkiller2

I was just playing around with it again and took it for another drive. I can hear a very distinct whistling sound up to about 2k rpms.

 

I am hardly a mechanic, and correct me if I'm wrong, but wouldn't a leaking valve lead to overall poor performance? Would it be possible that it would only affect the idling.

 

Since I saw all the smoke coming out from underneath the intake manifold I feel like I should get the new gaskets pull it off and see if anything is going on that I can't see from above. I've been all over the net trying to find answers. Similar symptoms on same model cars have all said the IAC or a vacuum leak. After taking off the IAC and seeing it was working, I guess I'm forced to look over the vacuum system and look for leaks before moving on.

in all honesty, 19 yr old vacuum hoses should probably be replaced anyway - dry, brittle hoses dont seal very well.

 

That said, I would be trying very hard to determine exactly where that "smoke" was coming from - are you 100% sure it wasnt smoke from perhaps an oil leak dripping onto the cat and burning off?

 

Not saying you are wrong about where it is coming from, but there really isnt anything under the intake that could produce smoke...

I guess I could have been more specific. The "smoke" was the cigar smoke I was trying to blow into the vacuum lines to find a leak. The engine was off and cool so I don't think it was oil burning off. Never had that problem in the past. I disconnected about a 1" hose off the main air intake which lead to the IAC. Lots of smoke came out from under the intake manifold, (just replaced the gasket on the IAC) but as the smoke was coming out from underneath it was hard to see. I am trying REALLY hard to figure out the vacuum lines with my chilton manual but just get more and more confused every time.

I can hear air sucking like crazy but can't see what's going on short removing a bunch of the hoses and other stuff that's in the way

 

Another note: In my search of vacuum hoses I've been reading about a brake booster. When I go to brake and I get the severe idling issues when slowing down I can feel the brakes losing it. I have read about a check valve on this break booster which is there so that when vacuum is lost it should keep your brakes functional. First what the heck is the brake booster? Is it the same as the Master Cylinder? Is there potential of a vacuum leak there? Is that entirely unrelated?

 

Please pardon my lack of knowledge in regards to overall vehicle function, I am new to this and sorta flying solo.

 

Thanks for the responses!

Edited March 26, 201214 yr by beatersubi

I guess I could have been more specific. The "smoke" was the cigar smoke I was trying to blow into the vacuum lines to find a leak. The engine was off and cool....

 

ah, ok... thanks for clarifying.

 

the brake booster is the big round thing on the firewall, the master cylinder is attached to it, and yes, it does use vacuum to operate.There is a fairly large vacuum hose that runs between the booster, and the engine.

yeah, Ifeel kinda stupid now after seeing what the brake booster is. I checked last night after talking to my Dad.

yeah, Ifeel kinda stupid now after seeing what the brake booster is. I checked last night after talking to my Dad.

 

dont feel stupid, we all had to learn somehow at some point, some of us just learned it sooner than others is all.

All the same I checked out the hose, and I really thought I had it, but there is no change. I'm still hearing air sucking. Did some more research. I'm getting very small miss fires occasionally and read about leaky o rings on an injector. I'll probably pull off the intake manifold and replace all gaskets and replace the o rings on the injectors. It;s going to be on the back burner now though. I have to start work again.

I started this a long time ago, but haven't had enough time to work on the car. I had gone over everything and I just had a feeling it was the gasket for the intake manifold. After getting most everything off the top of the intake, we could see where the gasket had blown out. Got her fixed up and she's purring like a kitten now. Reasonably easy fix. You just need to be mindful of how to take things off and how to put them back on. Two guys makes it go a lot easier when placing the gaskets and putting bolts back in.

well, glad to hear you got the problem solved!

 

and thanks for coming back and updating this thread - it DOES help when someone is searching for a solution to a similar problem.