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Because carburetors are easier to work on than electronic fuel injection systems, right?

You hear it all the time: I don't like these modern cars with their computers and newfangled electronics. Just give me a points ignition and a carburetor! Well, maybe that philosophy works for a your '53 Kaiser Dragon, but the increasingly tortured measures taken by the automotive industry to make carburetor-fed engines comply with ever-stricter tailpipe-emissions standards led to some real craziness as the 1980s progressed.

What does your carburetor do when it encounters edge-case situations— say, you're climbing a steep grade at 9000 feet elevation and 115° ambient temperature when you suddenly lift off the throttle— and the car can't barf out a bunch of unburned hydrocarbons or lung-searing compounds of nitrogen, like it was allowed to do in the old days? More sensors, more solenoids, more vacuum-operated devices, and more madness got piled onto ordinary carburetors, but in the case of the Honda CVCC engine, with its auxiliary combustion chambers and rich/lean dual-circuit carburetor, the tangle-o-spaghetti under the hood became, well, terrifying.

I see the notorious CVCC Vacuum Hose Routing Diagrams beneath the hoods of mid-80s Hondas all the time when I visit wrecking yards, and now I've managed to score a genuine NOS underhood decal. Let's enjoy the complexity… and look upon our EFI engines with new appreciation.

I've owned quite a few CVCC-engined Hondas, including this much-loved pair of

I've owned many members of the Honda Civic family, and I have a special affection for the third-generation Civic/CRX, sold for the 1984 through 1987 model years. During a period from the middle 1990s to early 2000s, I owned several apiece third-gen Civic hatchbacks and CRXs, but then the emission-test regulations of the State of California— where I lived at the time— became much stricter and it proved impossible to get one of these cars to pass the dynamometer-based tailpipe test. It would run fine, sure, but one of the dozens of incomprehensible devices lodged in that tangle of hoses would malfunction and the car would burp out excess carbon monoxide for a fraction of a second during a gear change or something: TEST FAIL. I tried to troubleshoot the problems a couple of times, but puzzling out the finer details of supersymmetry is much easier.

I think the problem must lie in the #2 control box.

Shockingly, this system worked great anywhere outside of the smog-check station; the mid-80s Civics (and Preludes and Accords) with the CVCC engines were quick (for the era) and got staggeringly good fuel economy. I touched a real-world 50 mpg in an '84 CRX with the 1500cc CVCC engine— not the ridiculously stingy HF model, mind you— and it wasn't slow. But… well, just look at this diagram!

Honda was kind enough to spend a few extra yen to print identifying numbers on all the vacuum lines (which were packed so thickly in the engine compartment that they'd hold the intake manifold in place, suspended, when you removed the cylinder head), but that only served to give you the illusion that ordinary mortals might somehow understand and conquer this system.

Here's what the Vacuum Hose Routing Diagram looks like after a few decades under the hood.

Of course, the diagram you'd be squinting at under the hood of your Honda wouldn't look like the nice, clean one I've scanned for this article. No, it would look something like the one you see above. Let's see, is the #31 hose— or is that #81?— properly connected to the vacuum solenoid that closes only when the car is idling at a drive-thru laundromat in Yreka? Hard to say!