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Señor Brat

85 Brat stalling at cruising speed... Help?

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Hey all, long time reader first time poster here.

 

I'm hoping one of you subie geniuses could help me diagnose a wired problem with my 85 GL Brat..

 

Details & Symptoms:

 

- starts quickly, runs great & drives great for about 5 - 10 miles (varys each time)

 

- after reaching normal temp & driving steadily for a few miles the car starts to hesitate a bit (not much, barely noticeable)

 

- its typically after a stop that the real problem hits.

 

- takes off normally but after reaching 2/3 throttle or so, it completely loses power and seems like there's no fuel whatsoever reaching the engine, forcing me to limp over to the side of the road.

 

- From that point on, even in neutral, the car struggles when the accelerator is pressed and wants to die unless I floor it.. It idles flawlessly.

 

- problem didn't start until after the maintenance listed below....

 

 

 

Recent Maintenence

 

- Changed plugs, cap, rotor (forgot wires, doh!)

 

- seafoam treatment

 

- oil, air filter, both fuel filters (twice)

 

- radiator, thermostat & more....

 

 

 

Suspects

 

- carburator? I cleaned it but it seems like its getting too much air & o fuel when it's dying. Weird thing is it runs fine for a few miles while cold/at temp

 

- cat? The exhaust is probably the most neglected system on this vehicle. I know little about cat symptoms and have tried to search the forum but couldn't tell if it truly is the culprit..

 

- pcv?? I doubt it, but i popped off the t connector on the drivers side of he engine bay, and it was pretty gummed up so I shot it with some Seafoam spray and let it set before starting it back up, but the problem persisted...

 

ANY HELP IS APPRECIATED AS ITS SNOWING AND I WANNA PLAY, haha :headbang:

 

Thanks!

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Suspects

 

- carburator? I cleaned it but it seems like its getting too much air & o fuel when it's dying. Weird thing is it runs fine for a few miles while cold/at temp

 

- cat? The exhaust is probably the most neglected system on this vehicle. I know little about cat symptoms and have tried to search the forum but couldn't tell if it truly is the culprit..

 

- pcv?? I doubt it, but i popped off the t connector on the drivers side of he engine bay, and it was pretty gummed up so I shot it with some Seafoam spray and let it set before starting it back up, but the problem persisted...

 

1) Carburetor - Possible. Dirty, gummy carburetors do funny things

 

2) Cat - Not likely. A plugged cat will cause the car to bog down when you step on it, especially at higher rpms. You'll hear a deeper noise from the engine as air "stacks up" in the intake manifold. If the cat was plugged it would run bad all the time.

 

3) PCV - Not likely. Spend the $3 and replace the valve since it's gummed up, but I doubt it's your issue

 

 

4) My best guess (I'm an ASE Certified Master Auto Tech) - It sounds like your coil is dying. Coils will tend to get worse as they warm up, and it takes more energy to fire the plugs under load than it does to idle. It could also be a bad ignition wire from the coil to the distributor. You can check resistance on the coil and on the wire, but in my experience resistance tests will only show a bad part maybe half the time. You might be able to catch it in the act by testing resistance both cold and hot. Resistance values should be listed in any repair manual (there's a bunch online if you don't have one). I can look them up if you need me to.

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+1 on the coil and fuel pumps will do the same thing. The windings get hot and short, then cool down and open back up. You need to check for fuel and spark when it happens.

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Hmm, didn't think of that but you might be on to something!

 

I was actually thinking of replacing it with an Accel supercoil (I believe this is the one without the horizontal mounting issues I've heard about) last month with the rest of the maintenance, but passed on it.

 

I have 160k and it's all original, so I figure it's about time regardless.. I'll grab my dvom and let you know the results.

 

Only thing that had me thinking Cat was that I seafoamed it to high hell for the first time ever and figured that could have caused my cat to plug up, but from what you described, I think the coil is the prime suspect.

 

Thanks guys, this forum is awesome!:banana:

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Also on the subject of the supercoil, I vaguely remember reading somewhere that I may need an extra resistor (can't quite remember) to install the supercoil due to the higher voltage?

 

I could be mistaking but thought I'd ask just in case...

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I wouldn't bother with an aftermarket "upgrade" coil. An oem-equivalent coil is all you need. Our cars are low-rpm and naturally aspirated (or low boost pressure on turbo models), so the advertised extra spark capability of an aftermarket coil will never be utilized.

 

If you do go with the supercoil you need to find out what feed voltage the coil requires, and then find out what voltage the stock wiring provides to the coil. They need to be the same. Typically coils are fed 5 volts while running, though some run at 7.5V and 12V I think. If the supercoil is a 5V coil and the stock wiring is a higher voltage, you will need to wire in a ballast resistor to drop the voltage to 5V

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So I swapped over the coil from my 82 and alas, the problem persists.. Now it's bad at idle warm or cold.. Back to the cat perhaps? It does sound like too much air is being sucked down by the carb, which could be what you were describing about the air backing up in the manifold.. Any other suggestions?

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I really doubt it's the cat. You can unbolt the header and try driving it to rule it out if you want.

 

Since the coil's not the problem I would suspect the carburetor. Make sure the fuel is up to the dot in the float level window (rules out fuel supply to carb problem, at least at idle). Try blowing carb cleaner down the main jets (visible when you look down the barrel of the carb) to clean them out. If you put the seafoam in the gas tank it may have knocked a bunch of stuff loose that is now blocking passages in the carb. One trick to easily clean out the carb bowl is to rev the car up to 2500+ rpm then stick the palm of your hand over the top of the carb, sealing it off. This will cause high vacuum in the carb which sometimes sucks out the stuff clogging the jets. Wear a leather glove when you do this! Last time I did it I ended up with blisters where the skin on my hand literally got sucked down into the carb.

 

Did the problems start shortly after getting gas? You might have gotten a tank of bad gas.

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So it seems like its a problem that has gotten progressively worse since I did the seafoam treatment. The car had been sitting for 4 months with a near empty fuel tank. I did a basic tune up as I mentioned above and the car ran better than it had in years, to my surprise.

 

Shortly after I noticed the car could struggle to get over 60 mph indicated when going up a slight incline. I could notice a very slight misfire, but not enough to make the car hesitate, just seem slower than normal, haha.

 

It really felt like a fuel filter issue so I replaced the rear again and added some heet with the next fill up. No help, car died on the highway a few days later, I filled up with some premium & no additives and it seemed to help for a bit.. But then here we are.

 

So after the new coil and wires it idles smooth (like before) and revvs smooth at about 3k plus. It's just when I "accelerate" that it stumbles, seems like its going to die for a split second, and then revs up to 3k and holds fine. It does sound like the exhaust is popping and choking when it's in that stumble phase and backfires immediately after... Maybe I'll post a video if I can figure out how to post.

 

Thanks for all your help, if anything, I'm learning a lot from this experience, haha

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From the sounds of it, I'd think it's fuel related. I note that you already replaced BOTH fuel filters. However, considering the weather and that it's been sitting four years you might do the filters again; especially the lowere fuel filter. But before you replace it again, drop in some "dry gas" and Seafoam with a full tank of gas and wait until you're down to half a tank before installing the fuel filter by the fuel pump. You might have some crap in the bottem of the tank that needs to be filtered out before it will run normally at speed.

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That really sounds like a carb problem.

 

Ok so upon closer inspection of my carb it seems like the secondary jet isn't spraying fuel on hard acceleration. I'm not exactly sure how these beasts work but here's a vid of the problem:

 

 

In the video, When I pull the throttle cable the primary jet seems to hesitate a bit and then dump fuel, thus raising my rpms. As I said, I'm not too familiar with these carbs but I feel the secondary isnt doing something it should be...

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From the sounds of it, I'd think it's fuel related. I note that you already replaced BOTH fuel filters. However, considering the weather and that it's been sitting four years you might do the filters again; especially the lowere fuel filter. But before you replace it again, drop in some "dry gas" and Seafoam with a full tank of gas and wait until you're down to half a tank before installing the fuel filter by the fuel pump. You might have some crap in the bottem of the tank that needs to be filtered out before it will run normally at speed.

 

Did both of those again when I suspected an issue... No dice. I've gotten about 3 tanks of gas through 2 sets of filters (this set I actually may have installed one backwards I just noticed :banghead:) and the problem became more persistent.. It's getting frustrating

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With the car shut off, hold the choke open and pull the throttle cable. You should see the accelerator pump push a jet of fuel into the primary barrel. A nice strong jet of fuel.

 

This is how the carb is supposed to enrich the mixture when you snap the throttle open like in the video. It sounds like it may not be getting a good jet of fuel from the accelerator pump.

 

Your secondaries cannot be tested like in the video. This carb uses vacuum to open the secondary under heavy load, which you cannot achieve by revving the motor in neutral.

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On the side of the carb is a vacumn pod underneath a rod goes to the arm that moves secondary butterfly. Try throttling the carb and moving this arm at the same time while looking into carb. this will make primarys and secondarys open Now just throttle hard and see if back butterfly is pulled open with vacumn. if not rebuild carb. Note Did 3 carb rebuilds last yr for same problem

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UPDATE:

 

So I finally gave in and took it to the local mechanic who suggested it was the exhaust system. After replacing it, the car seemed to run & drive like it should, albeit a tad bit underpowered (but no hesitation, sputtering, stalling, etc).

 

However, about three weeks after replacing the exhaust from the cat back, the problem came back with a vengeance... Unless I hold it at 2/3 throttle and 3000 RPM+, it wants to die, and even then, its hesitating badly..

 

Suggestions?

 

I tried to test the accelerator pump as suggested earlier, but I do not see a jet of fuel so I may be looking in the wrong place. anyone have a photo/vid of what I should be looking for?

 

Thanks all

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I hope your search for the fix works I'm following your post. I have a 1986 lifted GL wagon that seems to be having similar issues, I just bought/ordered fuel filters. Mine is strange because the car will pull strong through 1st and 2nd but once it hits 3rd about 3000rpms it seems to sputter out, wont die on me but lack of power for sure, it seems that it's better off in 5th gear with 2500rpms than 4th with 3100rpms. I am going to have to check the carb tricks to see if that's it but still unsure. I could certainly use any help/advice out there.

 

James

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Still working on it, the problem is intermittent but happens more often than not.

 

I decided to start at square 1 and replace my fuel filters again, as there is a little gunk/debris in the rear filter, but I've definitely seen worse and I really dont think this is the case, but may as well check again..

 

Most recently I just went out and started her up (started fine, choke worked). Then after letting it warm up a bit (not to normal op temp) I touched the gas, choke disengaged, idles fine.

Then I give it another tap (as if I were about to take off in 1st) and RPM's drop, almost dies.. I spray around with some carb cleaner looking for leaks and found nothing.

 

Then I go back to the fuel filter, notice the bit of loose debris and an air pocket, so I shook it, turned it upside down, etc and the problem seemed to go away (at least in neutral at idle). It revved fine (not perfect, but good)so that is what is leading me to believe maybe my filter got a big chunk of something that is just clogging the outlet... Still has that air pocket, but from what I know, that shouldnt cause a problem like this.

 

This has been quite a puzzle... any insight appreciated...

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Ok lets check this carb. take off the top of the air cleaner, with a flash light look to the bottom of carb. with engine off either throttle the carb by hand or have some one else step on the gas pedal. the front butter fly will open (directly connected to throttle cable). so if you look to the back butter fly or throttle plate it will be closed. this opens with ported vacumn. ported vacumn only occurs on hard accelaration. So now start the car and look into the carb and throttle the carb. Look to see if the back butterfly or throttle plate opens. If yes, carb may not be problem. If no, internal vacumn leak. (note on 85 to 87 vacumn comes from a line that can carbon close. ) Rebuild carb and flat file the side of the carb where the vacumn pod is attached and file the vacumn pod. Gotten into this with board before flat file bottom of bowl and top and bottom of base plate.

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Again...... Fuel pump getting weak.... :horse:

 

If it were the fuel pump, wouldnt it have trouble running under load/at highway speeds once the bowl is empty? The problem just feels like a flat spot at about 1k-1500 rpm with a very slight miss once it's above those rev rates.. I'll look into the pump this weekend after I change the filters and drain the tank, but if it is a 'weak' pump how would once go about testing it? Wouldnt bench testing just tell me if its operational and not if it's weak/on its way out? Would a fuel pressure test tell me this? It's complicated because it's so intermittent at idle..

 

Thanks for the responses guys, this board is very helpful

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Ok lets check this carb. take off the top of the air cleaner, with a flash light look to the bottom of carb. with engine off either throttle the carb by hand or have some one else step on the gas pedal. the front butter fly will open (directly connected to throttle cable). so if you look to the back butter fly or throttle plate it will be closed. this opens with ported vacumn. ported vacumn only occurs on hard accelaration. So now start the car and look into the carb and throttle the carb. Look to see if the back butterfly or throttle plate opens. If yes, carb may not be problem. If no, internal vacumn leak. (note on 85 to 87 vacumn comes from a line that can carbon close. ) Rebuild carb and flat file the side of the carb where the vacumn pod is attached and file the vacumn pod. Gotten into this with board before flat file bottom of bowl and top and bottom of base plate.

 

Thanks for the detailed response, I'll be doing that later today. Which vac line are you referring to that clogs with carbon? I went through it a couple days ago and cleaned out the PCV lines and will be replacing the filter tonight but those are the only lines I spotted with any build up.

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I'm working on my spare 306-22..

Too much gas in my case.. Stuck float.

 

In theory..

 

Looked up the characteristics.. And among them..

 

My issue and then.. Yours?

 

" * A flooded carburetor is another symptom that the carburetor float is sticking. The float is stuck in the open position, allowing fuel to run freely into the reservoir and then into the intake manifold. Once too much fuel is allowed into the carburetor reservoir, the carburetor floods and cannot be started until all the fuel is expelled from the reservoir.

 

 

Engine Stalls or Hesitates

* The engine will begin to stall or hesitate when the carburetor float sticks. This symptom develops under driving conditions when the operator attempts to accelerate. The engine will act as though is it going to die, but catches and begins to accelerate normally. The hesitation of the engine is a similar event."

 

See also:

http://www.autozone.com/autozone/repairguides/Subaru-ff-1-1300-1400-1600-1800-Brat-1970-1984-Repair-Guide/Carbureted-Fuel-System/Carburetor/_/P-0900c15280065ae8

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Yesterday I took off the air cleaner and thoroughly cleaned every vac line in sight, noticed that (what I think is) the accelerator pump boot was torn and pretty gunked up inside so I shot that liberally with some carb cleaner, and it seemed to restore some of the up/down movement, then I just shot carb cleaner in just about every oriface I could get to without tearing down the carb (which I will most likely end up doing next week anyway).

 

Then upon reassembly I noticed one of the hoses that connects to the top of my passenger side valve cover had literally severed in two and that the nipple was clogged to high hell with crud. I cleaned this, cleaned out the lines for the EGR and PCV, buttoned her up (minus that valve cover hose), and started it and she seemed to run better.

 

Still had somewhat of a flat spot at that 10-1200 RMP range but picked up after that. Still think the problem is there, but at least todays work seemed to help a bit.

 

I will be replacing the fuel pump (got a new one for free!) tomorrow, but if that doesnt work, theres just the carb left that could be the problem... correct?

 

 

Thanks All.

 

SB

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So after further review, I believe the problem IS a failing accelerator pump. The problem was intermittent which made it tough to pinpoint, and the brass nozzle WAS spraying fuel ok (but now i am thinking it must have been a "weak" stream). Currently there is no fuel being sprayed after I 'cleaned' the top of the carb so that just leads me to believe that whatever it was that was diminishing the flow has now completely disabled the AP.

 

So, seeing as I have little experience rebuilding carbs yet would like to learn more, I think I may take the Weber off my 82 Brat and rebuild that (as i've heard it's simpler/less finicky) then do the swap.

 

I'd like to find a few more sources detailing the swap or rebuild (the ones I've seen have left me with many unanswered questions).. links?

 

thanks to the board!

 

SB

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