Dies at Idle

[SakoTGrimes]

But only at idle, warm or cold. Runs perfectly otherwise. I'm sure this is a carburetor issue, but before I start turning the wrong screws the wrong way, could someone point out which one I should be turning?

 

86 EA82 stock carb

[ferox]

If it dies at idle and you haven't turned any screws yet, then it means you shouldn't turn any screws. It probably means you need to clean some gunk out of your idle circuit, check your anti-dieseling solenoid, or eliminate vacuum leak(s) to begin with. If you turn screws and you are not familiar with tuning carbs or I should say, Hitachi carbs, then it will only make it harder to tell if you have eliminated the likely culprits later.

 

I just went through this myself. The paper element in my fuel filter detached from the filter body and my idle circuit plugged. It would run fine on the secondary, but would not idle at all. I rebuilt the carb, and ended up taking it apart two more times for cleaning with solvent to no avail. I had been planning to buy an air compressor soon, so I used this as an excuse to go for it. The magic blow-gun, when liberally applied to the idle circuit, finally got it cleared and the machine runs like a champ again. Just make sure if you pull the choke body and use air on the passages, that you remove the little plastic ball in the accelerator pump sump and the injector weight because they will go flying if you hit them right with the air.

[SakoTGrimes]

Ferox, I looked into my copy of How to Keep Your Subaru Alive, and it also said the cause of an engine not wanting to idle (but run fine at higher RPMs) was likely the anti-diesel valve. It said the ADV is a hexagonal, thumb sized brass thing on the drivers side of the carburetor pointing to the left headlight, but when I searched there, I could not find anything resembling that. But, I also have a blasted AC compressor blocking part of the view. The book also said that I should hear a clicking sound when the ignition is on and the ADV is disconnected, then reconnected. Since I could not find the valve obviously I didn't do that, but I do hear a constand noise coming from the PASSENGER side of the carburetor. I did not see anything moving or obviously making noise. Sounds kinda likea fuel pump does, but it could also be interepreted as a constant rapid clicking. This is an 86 Hitachi carb, which should be covered by the book, but the words there and what I'm seeing just don't match up..... ??? Could the anti diesel valve be somewhere else?

['84 Flat-Four]

Have you taken carb cleaner and checked for any vacuum leaks?

Are your spark-plug wires good? on tight?

 

If you have, don't mind me... just my thought process... and that's not a very long process :-\

[Buddy]

check the stove pipe that goes from the air intake down to the exhaust below. i had a similar problem and after i put in a new pipe it solved the problem. check that out too...

[ferox]

Ferox, I looked into my copy of How to Keep Your Subaru Alive, and it also said the cause of an engine not wanting to idle (but run fine at higher RPMs) was likely the anti-diesel valve.

It is certainly possible, but I would think that a clogged idle circuit is more likely. The anti-dieseling solenoid is a pretty durable part, but it does need power so it has two things to check on it 1) Does it get power 2) Does it function when powered.

 

It said the ADV is a hexagonal, thumb sized brass thing on the drivers side of the carburetor pointing to the left headlight, but when I searched there, I could not find anything resembling that.

This is true for the EA81 carbs, and I assume it is the same on an '86 EA82. It's a 19 mm hex that is about an inch and a half long or so(the author of HTKYSA must have very small thumbs), and it does stick out of the front of the drivers side of the carb diagonally toward the drivers side headlight...on an EA81.

 

The book also said that I should hear a clicking sound when the ignition is on and the ADV is disconnected, then reconnected.

With the car off and the key in the run position you may be able to hear the solenoid click when you connect and disconnect power. It will only click once per connect or disconnect. If I have time in the next couple days I might be able to post some pics and description of how I diagnose the ADV. It's a very simple part, and once you locate it, it's an easy check.

[SakoTGrimes]

Hey, thanks for the info. I am out of the country for a few more days, but I'll be able to tackle the problem when I get back. Since this car is not my daily transportation I can take as much free time as I want to figure out how to fix everything the right way (rump roast opposed to my old way of fixing it just enough to get me to work and calling it good, ha)

[SakoTGrimes]

Is this thing my ADV?? It's the only thing that even remotely sounds like what the book describes, and is the only thing on the carb with a wire, but it points out of the passenger side of the carb.

 

[SakoTGrimes]

Annnnnnnnnnnd, bump!

 

Still not sure if I have found the ADV or not. More info: when car is super warmed up, coasting off the freeway, she will idle fine for a while and not sputter. Would that make it something other than the anti diesel valve? Would it be bad to turn up my idle screw a little?

[wagaru]

i wouldn't adjust anything till we discover what the issue is. or you get whats called a "false" idle. this masks potentially harmful issues that will go on hurting your car until something breaks. then you will have to figure it out AGAIN, and have to re-tune your idle...again. when i started restoring honda mopeds and scooters i made that mistake a time or 2, and having it idle perfect in the shop and then give up on a customer 5 minutes after pick up, it was pretty embarassing

[ferox]

The anti-dieseling valve is just a possibility, not necessarily a probability. Have you pulled off the choke body from the carb and blown out the idle circuit with compressed air? It is not uncommon to have to use mechanical and chemical methods to get these carbs cleaned up.

 

I am unfamiliar with the part of the carb in your picture. It must be an ea82 thing. I wouldn't worry too much about the ADV until you have made all efforts to clean the idle circuit.

[SakoTGrimes]

The anti-dieseling valve is just a possibility, not necessarily a probability. Have you pulled off the choke body from the carb and blown out the idle circuit with compressed air? It is not uncommon to have to use mechanical and chemical methods to get these carbs cleaned up.

 

I am unfamiliar with the part of the carb in your picture. It must be an ea82 thing. I wouldn't worry too much about the ADV until you have made all efforts to clean the idle circuit.

 

No, I have not cleaned out the idle circuit. And I'm somewhat ashamed to admit it's because I don't know what that is. Is it a tube in the carb or something electrical?? So far all I have done is used some carb cleaner while the engine was running (back when it would idle) haven't turned any screws or anything.

[ferox]

The idle circuit is just the system of passages and brass metering bits within the carb that supply fuel and air at idle, which sounds straightforward, it's the identifying them on the carb part that is difficult. Unfortunately, I think the ea82 is sufficiently different than the ea81 that I can't point you to the correct place on your carb. I do think the part in your picture must be the ADV.

 

Since no one else has chimed in about ea82 carbs, I suggest you get a manual (even the Haynes has a decent enough carb section) and use it to either identify the idle parts and pull the choke body off the carb to get to them, or, use the manual to do a rebuild. The rebuild is easier than it sounds, just be systematic.

In either case, before you blast compressed air or solvent down the passage I suggest screwing the idle mixture screw in until it stops and count the number of turns so you know where to set it back to later (very important). After you know the number of turns, completely unscrew the idle mixture screw and remove it. Then blast away, and follow-up by blasting through the idle mixture screw hole before you screw it back in.

 

Also, the ADV needs to be removed and either a finger placed over the hole, rubber stopper, etc,... or the solenoid "plunger" removed from the solenoid housing and the housing reinstalled during the blasting. Just make sure the inards of the solenoid are put back together correctly.

 

Sorry if this doesn't help much. Owning a carbed vehicle in this day and age inevitably means you have to be able to work on it at least a little bit, because most mechanics don't know a thing about carbs and do not want to touch them. So if you are going to keep the car the way it is, ya might as well dig in. If this seems like a bit much and cash is tight, you might try to swing a used Weber off of the For Sale section.