my carb has a brain

[bgd73]

hey. would like a carb experts advice. I blew apart (literally) my old subes exhaust for the 37th time in 12 years. ok, I really do not know the number, but my carb sube is the animal.
I finally stepped up the axleback part to 2.25 inches, its been an up-and-over mystery for far to long now, I let it have some room. two inch straight mid, and two inch full chambered dynomax (the boxer rumble very mellow). I could not wait to get out on the highway and return to very high fuel mileage. To my dismay it went to 15mpg. I did not know this was possible for 1781cc, and no notice in power change or smoke. It is a feedback hitachi, and I reset it. I still smell it as rich near the new pipes, but normal out the back. What is going on? I have had to wait for the carb to synch in in the past, but pipes are different now, aluminized. Have I changed something in the feedback stuff with less electrical resistance? anyone any ideas? I haven't called this problem permanent, but would like it defined. I did take note after resetting battery, a few miles of chores with 1.5 gallons in tank went without guzzling (I kept it low thinking there may be a leak , and there isn't).

[evolutionmovement]

EA81 or EA82? In my experience with EA81s, the Hitachi was the better carb (vs. Carter-Solex). Aside from the general questions: does the car run alright (aside from rich), how's the O2 sensor, vacuum hoses all intact, EGR and PCV OK? Could be the carb is stuck in cold-start mode. There's a solenoid that allows more air in after the car's warm. I don't remember the particulars about it as I haven't had one of these in 12 years (though I'd love to find an '84 hardtop 5 speed, as rust-free as realistically possible) and never an issue with the carb anyway. Don't know what they did with EA82's.

[Frank Lee]

Oh for the thermodynamically superior flat engine to suffer this malady! To drop from 80 mpg at 78 mph down to 15 mpg is warping my cerebral cortex in such a way as to make it indistinquishable from, say, the turbulent gasses swirling about in the Orion Nebula. Which, incidentally, is mimiced by the perfectly homogenous fuel/air composition of charge in the long, smooth, perfectly transitioned intake tract that only the Sube possesses! Well the diabolical schemes of the New World Order will not prevail!!! Even though more and more states are passing primary seatbelt laws that doesn't mean I will sit back and put up with this! Forthcoming is an investigation as to whether the regional summer fuel blend has another percent or two of ethanol in it. I'll drink to that! The inherent superiority of a crankshaft without counterbalance weights won't stumble, fall over, and cause a spill. But I'll have to step outside for that smoke.

[bgd73]

Originally Posted by evolutionmovement

EA81 or EA82? In my experience with EA81s, the Hitachi was the better carb (vs. Carter-Solex). Aside from the general questions: does the car run alright (aside from rich), how's the O2 sensor, vacuum hoses all intact, EGR and PCV OK? Could be the carb is stuck in cold-start mode. There's a solenoid that allows more air in after the car's warm. I don't remember the particulars about it as I haven't had one of these in 12 years (though I'd love to find an '84 hardtop 5 speed, as rust-free as realistically possible) and never an issue with the carb anyway. Don't know what they did with EA82's.

hey it did go back to normal. I forget sometimes....the egr had to be removed entirely (crazy part), there is no more sensors for cold and hot that I use, I leave one in the intake to fill the hole, and the other still functions playing with the feedback (at least it appears to be).

I have concluded,backpressure creates smooth thumps for the carb, 3 degree delay without exhaust, creates "snaps" things to dump more fuel, become inefficient. I drove wtih a straight open pipe to the parts store to finish the exhaust, as these engines at 9.0:1 aren't all that loud (3psi fuel, tiny intake, etc). I even passed police with it open, kinda funny.
anyway, when letting off the throttle, open piped, it is hellacious, very very loud, shakes the car. the air coming back though a 2 inch pipe is bigger than the intake...the carb simply stuck to open dump, full fuel. The trick with the battery does reset after the full piping,I forgot to do so before my 15mpg ride, and the car is stil sitting there with less than 2 gallons of fuel, with a freeze warning tonight for my locale , guage hasn't budged.
As the thermodynamically boxer is correct now, I look forward to drving it around like a tourist, in the 40s mpg.this summer approaching I see less of my model subes, and to know my model is 6 years older than alot of them (my neighbors "the last loyale" has not been seen- it was one of the last I knew of on the road locally, and that was a 90s version)

anyhoo, I'll be parking mine and selling in a few years for 15 million dollars.
thanks for replies, it was a matter of remembering how to reset it, etc.

[Frank Lee]

As is obvious upon examination of the starred Sube oval, at times the shortest distance between two points is not a line but a curve. Vive la difference!