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84 5-sp. Hitachi carbed wagon. Coming down steep hill today in 2nd. Shift to 3rd at bottom, feed some gas, BANG! backfired and stumbled as if running out of fuel Made it a couple hundred yards and it died. Wouldn't re-start except if cranked at full throttle, and then would barely run, and die if throttle backed off. No evidence of flooding so I think it's fuel starvation. Yes there's gas in the tank. Hot (40C/100F) day today but car runs cool. This carb has worked fine since re-build a couple of years ago, once I sorted out a mis-routed vent hose, and rigged a manual choke. It does backfire slightly during upshifts if I let the throttle close completely during the shift. I hadda leave it where it died till I know where to start looking. This is a pushrod engine so I don't suspect a cam drive problem. Any ideas?

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could be vaporlock

 

Actually it can't be vaporlock - vapor lock occurs when the fuel in the lines boils and prevents the fuel pump from getting fuel - since his pump is back near the tank, this would be impossible.

 

Check it again tomorow - might just start right up and you can get it home to diagnose.

 

Also - could be a blown Air Suction Valve - when they go, they usually melt the plastic silencer (muffler) and it often gets sucked into the carb intake and will jam the throttle plates. Check down in the carb for debris.

 

GD

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check the timing to make sure nothing has jumped. Sudden failure like this under those circumstances i would suspect jumped timing or the car digesting something like stated above.

 

nipper

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check the timing to make sure nothing has jumped. Sudden failure like this under those circumstances i would suspect jumped timing or the car digesting something like stated above.

 

nipper

 

EA81 - no belts.

 

GD

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EA81 - no belts.

 

GD

 

i didnt say anything about belts. i just said timing. there are gears, and they can go bad too.

 

 

nipper

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i didnt say anything about belts. i just said timing. there are gears, and they can go bad too.

 

 

nipper

 

Actually - I seriously doubt that has ever occured in the history of the EA81. Ask around - if you find any certifiable evidence to that effect I want to see it. Have you ever even seen the EA81 timing gears? They are about 3/4" thick..... maybe with enough grit in the oil you could wear out a set, but not before the engine loses it's oil pressure and blows a rod.... Maybe if you hit the car with a train....

 

And he needs to check a LOT of other stuff first - if it's still fireing at full throttle then the valves are working. There is only ONE cam, and were the timing gears broken, it wouldn't fire at all, and you would hear some serious, serious crunching and grinding noises - might even seize the engine.

 

Don't scare the n00bs man - not cool.

 

GD

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Actually - I seriously doubt that has ever occured in the history of the EA81. Ask around - if you find any certifiable evidence to that effect I want to see it. Have you ever even seen the EA81 timing gears? They are about 3/4" thick..... maybe with enough grit in the oil you could wear out a set, but not before the engine loses it's oil pressure and blows a rod.... Maybe if you hit the car with a train....

 

And he needs to check a LOT of other stuff first - if it's still fireing at full throttle then the valves are working. There is only ONE cam, and were the timing gears broken, it wouldn't fire at all, and you would hear some serious, serious crunching and grinding noises - might even seize the engine.

 

Don't scare the n00bs man - not cool.

 

ccGD

 

 

The backfire is what has me concerned that it is more of a mechanical issue.

I am an automotive engineer, and over the years I've learned never say never.

Again I said jump time, I didnt say broken. Things wear out. Also before the the site cut me off (anyone else having site problems) i was going to add check the distrubitor.

Simpliest thing to do is get a timing light and make sure the timing is correct. After that he can hunt down the laundry list of things, including a bad tank of gas or water in the tank.

 

Say when was the last time the poster got gas and where did he get it.

The car is awfully young by subaru standards to have a internal mechanical issue (but it does happen).

 

nipper

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The backfire is what has me concerned that it is more of a mechanical issue.

nipper

 

Backfire is exactly why I told him to check the ASV - they suck in fresh oxygen for the cat, and when they fail it creates a big exhaust leak - this will result in massive backfireing from the fresh oxygen mixing with unburnt fuel and being ignited by the hot muffler. Backfires can be forceful enough to blow holes in the muffler. I've personally seen quite a few of these fail.

 

GD

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Speaking of backfire, let's not assume that we know what the poster means.

 

Is the backfire a loud pop out the exhaust, or into the intake (muffled, under the hood)? Although we should keep it simple, verifying good ignition timing and checking the ASV (my pick, also), other possibilities include burned valve and blown HG (though both unlikely given conditions at failure).

 

*edit* - Coil, disty and ignition electronics also could be suspect, as if these are flaking you could get spark at the wrong time causing either form of "backfire".

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Well, now! That's what I call a response. I'll try to answer some of the issues raised, starting with my general experience. I started playing with cars by stuffing a 265 Chev into my pal's 47 Ford. That was before there was a 283, 327, 350, or any other V-8 Chevy. You other O.F.'s will know what I'm talking about. But this old bucket has been here for 5 years now and impressed the hell out of me by it's simplicity and toughness. Not to mention easy to work on. The cam is a gear drive as I see in the Haynes manual. I'll start by doing the timing light/distributor check, then fuel flow after the vapor separator. Assuming the pump will operate when the ign. is hot. The tank was 3/4 full when it backfired and quit, but not today - someone siphoned it dry where I left it yesterday. The backfire was just that - not a mechanical noise, and I would say it was on the exhaust side, not the intake. The ASV is a new one on me, and I'll definitely check that out. Nipper, your comments are noted with thanks. I concur. By the way it has the same symtoms with some replacement gas today. Thanks, we'll see what we find out tomorrow.

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My friend had bad play in his distributor that caused the rotor to hit the points in the cap and snap...it dislodged it and would let it "fire" at times.

 

Maybe you ran out of gas? These gas gauges aren't the most reliable.

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My friend had bad play in his distributor that caused the rotor to hit the points in the cap and snap...it dislodged it and would let it "fire" at times.

 

Maybe you ran out of gas? These gas gauges aren't the most reliable.

hti, good tip on the distributor. I'll check that. Gas gauge has never worked in this car. I just don't go past 600 km before filling up and zeroing the trip meter. Never ran out yet. Had 180 km on this (full) tank.

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Well, ignition, distributor, fuel flow, vacuum hoses all checked out. I was baffled. So I disconnected a controlled vent line - the one that exits the top of the carb at the driver's side rear. She farted and started, cleared itself out in a minute or so, and settled down to it's normal 600-700 RPM idle. Hooked the line back up and all seems fine. I'm GUESSING the backfire somehow affected this vent and caused the float to hang up - although there was always fuel from the accelerator pump. This vent line is hooked to a vacuum solenoid and in turn vents to atmosphere through a small orifice (I think!!) Not sure if it's normally open or closed. Any Hitachi experts out there care to comment?

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started playing with cars by stuffing a 265 Chev into my pal's 47 Ford.
not to hijack the thread, but I remember the 265 well. Do you remember the Bon Ami trick?

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:burnout: my soob did the same thing it wasen getting enough fuel i looked at the fuel filter anmd it was realy bad so i changed it and she ran great try that:headbang:

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Common on the Hitachi's I've noticed - you probably experienced a stuck float needle - I've had this happen a number of times with them. Only thing you can do is tear it down and replace the needle and seat.

 

GD

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Me again - spoke too soon. Went to town (5 miles) had to pull the vent hose off as it starved again. Ran ************ty with the vent open, except for idle or into the secondary. Can these little dollar-sized vac. solenoids be damaged by a backfire? In reverse order, GenDis - I concur re:stuck float needle. The carb got a Niehoff kit 3 years ago Shouldn't need another by now, should it? SubGuru, changed out front & rear filters last year to solve high-speed starvation. AZ, no I don't, but then again there seems to be more and more things I don't remember. PM me and remind me.

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Vac solenoid is easy to diagnose - actually if you want you can just remove it and connect the bowl vent line to the carbon canister directly. Basically I think removing the vent line changes the pressure in the float chamber and usually unsticks the float. I've had the same effect before, and then at other times when it stuck, pulled the vent line wasn't enough to fix it.

 

The Hitachi I've had the most difficulty with I rebuilt a grand total of 7 times. Eventually I had sucess with pulling a needle and seat from a junkyard carb and using that. It seems that the rebuild kit needle and seat I used were not of very high quality. The end of the needle was rubber, where the stock unit is solid brass. I have a feeling this may be part of the problem. Of course this is all conjecture as there really is no way to see what's going on in the darn thing, and by the time you take it apart, it's already fixed itself. :mad:

 

GD

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:)

Me again - spoke too soon. Went to town (5 miles) had to pull the vent hose off as it starved again. Ran ************ty with the vent open, except for idle or into the secondary. Can these little dollar-sized vac. solenoids be damaged by a backfire? In reverse order, GenDis - I concur re:stuck float needle. The carb got a Niehoff kit 3 years ago Shouldn't need another by now, should it? SubGuru, changed out front & rear filters last year to solve high-speed starvation. AZ, no I don't, but then again there seems to be more and more things I don't remember. PM me and remind me.[/quote

 

oh i know exactly what your talking about my sube did the same thing i never found out why the carb wouldent work i keped having to pull the vent hose off. i eventualy had to put another carb on unless you rebuild it.

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OK, let me try and describe what I'm looking at and see if anyone has the answer. Standing in front of the car, looking down on the carb. There are (on my 84 Hitachi EA81) 4 vent lines, all pointing to my right (driver's fender) I need to know where the rearmost one (located on the right rear backside of the top section of the carb), and the next one(located just above and behind the fuel inlet and return lines entry) go, and what they are connected to, as well as what exactly they affect. The other 2, one from beside the bowl vent solenoid and one from the front of the carb, haven't been disturbed. If I connect the rearmost one to the vac. solenoid, the car starves and dies. Open it to atmosphere, and I have good idle and full throttle, poor to no part-throttle response. The second one is connected to a .050" orifice, then atmosphere, and seems to have no effect on things. Anyone? (GenDis - I'm not discounting your needle-seat theory, just trying to work around that next move. SubGuru, your comments seem to maybe point to the same thing, but I don't have a yard within 20 miles. And I still need to know where the h--l these lines go and do.) Anyone??

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Wow - ok I'll have to dig out my FSM and take a look. I'll reply back when I can describe all that stuff in detail. I'm not going to commit to anything, but largely I think that stuff is evap related....

 

Before I go digging around in the FSM, I NEED to know if you have a feedback carb or not. Do you have an ECU under the dash?

 

GD

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GD, I'm not sure - it's a Can. car so maybe not. Tell me where to look under the dash - my Haynes manual is not clear on this nor the vac. line routings and purposes. There is a flat metal container around 4" sq. with a harness under driver's side above fuze box. That it?

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It should be directly under the drivers side kick panel - mounted to three studs on the steering column. It will have a round hole in the front to view the LED diagnostic lamp through..... we had them in most of the 2WD's, and all california models. Actually pretty common here on the west coast. The EA81 computers are generally black, with a pretty decent sized 20-or-so pin harness connector.

 

GD

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Definitely no ECU - just the empty mounting bracket. A brown 6-pin and white 4-pin plug are tied off and not connected to anything. Assume they are A/C and cruise harnesses, as the car has neither. I remember also when I installed the manual choke there were no electrical connections left over to wonder about.

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