Exhaust Q

[cd45]

My Soobie is still getting mediocre mileage, and it is also starting to lose power going up hills. I think that the problem is either the catalytic converter or there is a collapsing exhaust pipe. My question is, what is the other piece of equipment in the exhaust system? I know what the muffler is, what is the first one where the pipe Y's, and the next one back? Any one know?

[hooziewhatsit]

if all of a sudden you can hardly make it up hills, and there is a loud whistling coming from 'somewhere on the front of the engine' your cat is now blocked. Ask me how I know

 

Typically, all of our soobs had 2 cats, one at the Y pipe, and the other half way back. Beyond that is the muffler.

[idosubaru]

bad mileage and loss of power going up hills can be caused by many things. people tend to cry "bad converter or fuel pump" when they aren't sure what the problem is. unless you have more reason to believe the converter i'd diagnose this a bit more. i've seen lots of people replace converters and not solve their problems.

[karinvail]

bad mileage and loss of power going up hills can be caused by many things. people tend to cry "bad converter or fuel pump" when they aren't sure what the problem is. unless you have more reason to believe the converter i'd diagnose this a bit more. i've seen lots of people replace converters and not solve their problems.

 

I agree - there could easily be something else going on. My car doesn't even HAVE a cat (so I know it's not clogged!) and it loses power going uphill. All the Soob's I've ever had have been gutless going uphill though...... except for the Turbo FI sedan I had that was my first Soob - man, I miss that turbo!

[cd45]

I don't know what else it could be. I gave the car a good tune-up. It always lost some going up hill, now it loses 10 miles on the same hill.

[MorganM]

To answer your question on exhuast components....

 

Headers -> catalyitc converter (these both make your Y pipe) -> resinator -> midpipe -> muffler -> tail pipe

 

Do a compression test all around before you throw down several hundred dollars on exhuast.

[karinvail]

so, what is the 'job' of the resinator in the exhaust? (ie: what does it do?)

[NorthWet]

To answer your question on exhuast components....

 

Headers -> catalyitc converter (these both make your Y pipe) -> resinator -> midpipe -> muffler -> tail pipe ...

On all of my subes, the item you list as a resonator is the second catcon. (One catcon is a reducer, the other is an oxidixer).

 

When a "resonator" is used, its main job is to muffle frequencies that the main muffler does not handle well.

[[HTi]Johnson]

I know you said you gave it a good tune up...if this is an EA81...did you replace BOTh fuel filters? I'm not sure if the EA82s have 2...I know that MPFI doesn't. There is the one in the engine bay and the one in front of rht passenger rear tire. Right above some protective plating.

[HTi]Johnson

[MorganM]

On all of my subes, the item you list as a resonator is the second catcon. (One catcon is a reducer, the other is an oxidixer).

 

When a "resonator" is used, its main job is to muffle frequencies that the main muffler does not handle well.

 

I stand corrected then; it is part of the emissions control system.

 

I'd have to say it does both jobs also but its main job, as you noted, is an oxidizer. Now that I think about it; that does explain the air injection tube on the side of it

[NorthWet]

I stand corrected then...

You *stand* while typing??? You are a better person than I am!

 

I hadn't noticed an air pipe on any of mine, but the '88s are kind of new for me.

[MorganM]

You *stand* while typing??? You are a better person than I am!

 

I hadn't noticed an air pipe on any of mine, but the '88s are kind of new for me.

 

Yeah I'm in the server room at the exhange server rack; no seats! Acutally they don't let me in the server room unattended :-p

 

Hmm I remember a bung and fitting on mine and then a hose upto the engine bay. Can't recall where I unplugged it from under the hood. Might just be fore late model EFI modles? :-\

[85Sub4WD]

NorthWet and MorganM - you are both right - I looked in my '85 FSM, and 4WD carbed cars do not have a second cat - just a resonator, while some others do (all FI cars) - go figure

 

your problem does not sound like a clogged cat to me - fuel delivery system is high on my list, and compression is not far behind - your head gasket may be on its way out

[Sweet82]

I'm still curious about what you did on the tune up?

 

Give us a idea of what your tune up consisted of?

 

I have always found a tune up to be most helpful in getting these old beasts back in the game.

 

I'm guessing/hoping you did,

 

Plugs,

Wires,

Cap,

Rotor,

Front fuel filter

Rear fuel filter

Air cleaner,

Decals

 

That usually does the trick?

Did I miss anything?

 

Missing any one of these could cause poor performance and lousy mileage.

 

Glenn

82 SubaruHummer

01 Forester

[snowstormer]

if all else fails and you still think the cat might be plugged-

 

 

you can bring the car to an exhaust shop and have them do a "back pressure test". shops around here charge about 10 bucks for it.

 

then you will know for sure if the cat is plugged or not.

 

good luck

[cd45]

I changed everything you listed except the front filter. Where do I look under the hood, left or right, front or back of engine compartment? I found a broken pruge valve yesterday. According to what I found and read it has to be replaced if any oil or fuel is present. The problem is that no one local that I can find has one. The only thing left is the dealership. Any ideas?

[MorganM]

Looking at the engine, look right and up, behind the strut tower near the wiper blade motor.