Aiee! SOS! Save Our Subaru!

[DirtyMech]

I've been having a hell of a problem with my Subaru, and I'm wondering if anyone here has experienced something similar.

 

My car is a 1985 Subaru DL 1800 2WD @ about 179,000 mi. The problem is that it will not idle at low speeds. This is a problem that has grown slowly worse. I've tested the car at both cold and hot temperatures, and it dies at regular idle speed under both conditions. The battery is fine, and the starter motor will start the engine, but the engine dies shortly after unless I hit the gas or turn up the idle really high on the carburetor.

 

I thought at first that the problem might be with the carburetor (DCZ 328) so I rebuilt the thing and put it back on the engine. The automatic choke bell housing was loose, so I fixed that, but no luck with the idle speed problem.

 

Could this be a symptom of incorrect timing? I'm still waiting for my timing light to arrive in the mail from Harbor Freight before I can check to see (timing hasn't been checked for two years). Perhaps when I was rebuilding the carburetor I adjusted it incorrectly? I know that the problem has to lie within one of these four areas:

 

-Electrical System

-Fuel Delivery/Computer Controls

-Engine

-Exhaust

 

I'm hoping beyond hope that there's nothing wrong with the engine, although the problem might be due to a compression leak in one or more of the cylinders. Unfortunately I don't have a cylinder compression testing kit. The engine SEEMS fine, no odd noises, and at high RPM it purrs like a kitten. My best guess is that the fuel mixture is off at low idle or that there is something wrong with the electrical. For two year's I've been the only one to do any kind of mechanical work on my car, and I now I think that I might have to give in and take it into a shop.

 

But before I do that I'm hoping someone has an idea. Are there any other tests I can perform to try and locate the problem, or has anyone experienced a similar problem? All input is GREATLY appreciated!

[Humble Nuto 53]

im gonna guess its a vacuum leak.

fairy typical symptoms

 

if its not a cracked hose somewhere, it might be

the brake booster going bad

 

one method to find vacuum leak is use carb or brake cleaner

(highly flammable)

and shoot little squirts on the hoses one by one....

when your idle jumps up you've found the leak

[[HTi]Johnson]

Fuel filters? Have you replaced those...I believe there are two. The one in the engine bay...and that pesky one most people forget about...it's in front of the rear passenger tire, next to the fuel pump. I've had those prevent cars from starting. I've spent hours trying to diagnose problems and it's turned out to be a fuel filter.

Good Luck

[Cougar]

Along with the other suggestions I would look at the plugs, plugwires, cap and rotor. They may be due for replacement. Also check the intake manifold gaskets for a leak.

[DirtyMech]

im gonna guess its a vacuum leak.

fairy typical symptoms

 

if its not a cracked hose somewhere, it might be

the brake booster going bad

 

one method to find vacuum leak is use carb or brake cleaner

(highly flammable)

and shoot little squirts on the hoses one by one....

when your idle jumps up you've found the leak

 

Ahhh, you're probably right Nuto! Thank you for the diagnosis! That makes a lot of sense now that you say it. That'd make the idle mixture lean, causing the engine to die...and I never checked the intake itself when I was doing the carb rebuild. I think I'm going to take off the intake manifold and check the gasket seal, and then put the hoses back on one at a time and check them. If it isn't a vacuum leak, I'll make sure of it before I take it into a shop.

[DirtyMech]

Fuel filters? Have you replaced those...I believe there are two. The one in the engine bay...and that pesky one most people forget about...it's in front of the rear passenger tire, next to the fuel pump. I've had those prevent cars from starting. I've spent hours trying to diagnose problems and it's turned out to be a fuel filter.

Good Luck

 

 

Oh hey, on a side note, does anyone know exactly where the secondary fuel filter in an 85 DL is located (the one in the engine compartment) since Johnson mentions it? I'm not convinced that there even is more than one because when I was doing the carb rebuild, I traced the fuel line from the carbeuretor and it disappears under the master cylinder housing into the chassis wall. I KNOW about the one next to the fuel pump under the rear end of the car, the one next to the fuel pump (that ones easy). And yea I have replaced it, about 6 or 9 months ago. And when I checked the fuel in the float chamber it looked clear as tap water, which is a good sign. But thats a little off from my point.

 

Basically what I'm want to know is whether or not 85 DLs have two fuel filters, and if so where is the second one? If nobody is sure I'm gonna assume they only come equipped with the one.

[Cougar]

Intake manifold leaks are common. You should be able to listen for a leak by using a hose to your ear and down by the joint. Also spraying some WD-40 around the joint with the engine running can show one up. I had one so bad you didn't even need a hose to hear it.

[edrach]

EA81 cars have the two filters; one a true filter down under the car near the fuel pump and the other (actually, called a separator with 3 fittings instead of two) located in the engine compartment next to the master brake cylinder. I think they did away with the separator with the EA82 cars.

[subyrally]

idle air control valve, they let just enough air past the throttle plate when your foot is off the gas. keeps it from stalling.

[DirtyMech]

EA81 cars have the two filters; one a true filter down under the car near the fuel pump and the other (actually, called a separator with 3 fittings instead of two) located in the engine compartment next to the master brake cylinder. I think they did away with the separator with the EA82 cars.

 

Ahhh, that answers my question. My car's engine is an EA82. Thank you very much Edrach.

 

Subyrally, is the idle air control valve part of the carburetor? Where is it located? Is there a way to test it? I thought the carb's choke controlled air flow during idling...