'84 GL Wagon throttle delay (39K original miles)

[GeneralDisorder]

The Weber can be tuned to get good mileage. It will have to be re-tuned for each emissions test with a gas analyzer and then turned back for good mileage. Good economy/driveability and best emissions are basically mutually exclusive with a Weber. I have got up to 32 mpg with one, but for testing you will surely be retarding the timing and leaning out the idle mixture.

 

The computer is a non-issue. Simply unplug it and the light will go out. The Weber doesn't use it.

 

GD

[idosubaru]

They stated earlier it'll perform better including improved gas mileage.

 

didn't know they were not generally considered as good carbs..

I'm fairly certain that's a massive understatement. Idon't know that there's a more hated part ever used on Subarus.

 

Makes me wonder about the first 5 years they were new - surely they weren't problematic then? maybe that carb shop will dial in the Japanese one. Clearly they're not forgiving so how often will you then need to return to keep it maintained and running right?

[Sapper 157]

All your great replies are starting to sway me to the Weber. If I go with the Weber, assume there is no way to connect the carb to the computer. I was told by my mechanic that this could cause me to not get very good milage. I was getting over 30 until recently, now I'm at 19 (don't know why). Also, would the Weber cause the 'ECS' (Engine Control System) light to stay on on the bash? I would assume the computer would trigger this off as well. My ECS comes on all the time anyways and when it does, I notice a corresponding drop in power.

No offense intended but your mechanic is mistaken. Piggy backing on GDs post, a properly tuned Weber will give up to 30+ mpg hwy regularly and 25-28 in town. My average since installing my Weber in January is 25.6 mpg... but that is because I was doing a lot of warm up time in the winter, and the carburetor wasn't properly tuned. Now that the weather is nice and warm and it's tuned correctly, I get 26-28 around town, and 31 on the hwy, providing I don't gun it. As long as all other tune up stuff is good (clean fuel filters, no vacuum leaks, NGK spark plugs ONLY and NGK spark plug wires ONLY, clean disty cap terminals and rotor, timing advanced to 12ish degrees, valves tuned, and ignition coil in good condition) then really the Weber's mpg will depend almost entirely on how you drive it. It does give a small power boost over the Hitachi, so it's tempting to floor it constantly to open up that second barrel, but your gas mileage will go wayyyy down. So the moral of the story is drive it nice and it will do just fine mpg wise.

 

As far as why you are getting only 19 mpg right now, more than likely it's a vacuum leak coming from one or several parts of the Hicrappies mind bogglingly complex vacuum system. All of which you can cap off and eliminate as vac leak sources if you do the Weber swap.

Edited June 22, 2017 by Sapper 157

[pacerfrog]

Again more great responses! I wonder if the original virgin Hitachi carbs ran okay during the 1980 until Japanese parts ran out over the years? At this point in history, I doubt there are very many Subarus that don't have tons of Chinese crap under the hood.

[pacerfrog]

first of all, I agree with everyone who says to get a weber, I used to have a similar problem on an 86 hatch and I could not fix it until I swapped a weber and started playing with all the jets, and in the process removed most of the emissions systems. The hesitation made crossing a street from a stop sign into a pretty awkward and serious situation! Anyways, whether you get a weber or do not, the excessively complex routing of vacuum hoses to various devices could easily hide leaks somewhere, or worse yet, they could be operating the emissions devices correctly, which may be causing your problem.

 

Sorry if this is getting too wordy, but what I'm getting at is I think it could be either 1 duh vacuum leaks, 2 the egr valve "operating normally" or 3 a combination of special problems only for people who reside in california. But really, since the egr among other things are operated off of the ported vacuum aka the vacuum hose coming out of the carburetor, anything in that vacuum circuit can wreak havoc on your fuel mixture, but especially right when you apply throttle off of idle. (you likely already know this stuff since you've tinkered with the carb, but I'll continue anyways), the ported vac is basically a hole in the carb right next to the throttle plate at a specific height where it is above the throttle plate at idle, which exposes it to the atmospheric pressure inside the air filter, but as soon as you open the throttle plate a dash, the plate opens above the hole and you expose the port to the low pressure of the intake manifold. This sounds like the point where in your car, perhaps anything can happen? If the hesitation happens every single time, and seems to be super lean at low throttle even when you're not starting from a stop, I would suspect an air leak somwhere, possibly one of the hoses that go up into the air filter (I think some of those connections under the air filter are supposed to have orifices to restrict air flow, and others are possibly not? wouldn't want to mix those up, but what do I know, I don't even have the stock air filter anyways). If it only happens off of idle, and doesn't seem to lean otherwise, I would think that the higher vacuum generated at idle suddenly being exposed to your ported vacuum could be enough to open your egr valve all the way, initiating a stall until the vacuum drops enough for the valve to close up enough for a decent fuel mixture to reach the cylinders, and then the hesitation is over, and you wait until the next stop light to see if it'll happen again. Once your away from the stop, the egr primarily operates under high vacuum aka very light engine load, but right when you leave a stop, the egr gets confused by the anomalous high vacuum and HIGH load, and spoob hits the fan. One thing about this problem is that the egr won't run at all unless the underhood temperature is relatively high, as the heat opens a thermovacuum valve that exposes the egr to the ported vac. That means that when you first start the car, it won't happen, but if you shut the car off for a while, the engine may cool down, but not cool down enough to close the thermovacuum valve, so when you leave the grocery store after a half hour of errands, the egr snaps open in your slightly cooled off engine, and you start running your starter motor to limp yourself out of a busy intersection.

 

Does that sound like it could be your problem!??!? I hope I'm right, because I would hate to have written such an intimidating and bloated paragraph just to be way off the mark, but I hope that gives some insight anyways. IF this sounds like your problem, I would recommend fitting a vacuum delay valve aka a spark delay valve into the vacuum hose going directly to the egr vavle. This type of valve lets air pass normally in one direction, and very very slowly in the other direction, like a one way orifice basically. If you face it the right way and allow air to travel very slowly from the egr to the carb, and normally from the carb to the egr, the egr will open very slowly, and close very quickly, it could take long enough to open to prevent any stumbling, but still open enough to kick in during long straight road cruising conditions. You can find some generic vacuum delay valves for other random vehicles, probably fords and whatever, who really cares. as an example, or just try this one, try a part number search on rockauto for part ec308.

 

If you're still not going to do the weber swap, you can maybe try a few of the mods people do when they swap for webers, like run your distributor advance diaphram directly to your intake manifold and not to your ported vac (known to reduce exhaust temperatures and make the engine run smoother and have better off idle response, but may create more NOx crap that the epa doesn't like, especially in california apparently).

 

Hope that helped....... if anyone read it, sorry again for the excessively long post

 

Long, but good stuff.........