1981 Honda Civic- Better FE suggestions?
 

I have an 81' Honda Civic Wagon. 12 valve EM1 CVCC engine. 5spd standard. 1750lbs curb weight. I have been averaging about 36 mpg.
I have already been using the pulse and glide technique and I put in Pulstar spark plugs. And I run mobil 1 10-30 synthetic oil.

Does anyone have any ideas on how I can maximize my FE with a carburated car other than driving technique alone?

Thanks.

Your speed and driving conditions might help

Is the carb properly tuned?

maybe
 

I believe so. The choke pull off diaphram needs replaced. The warm idle speed seems a little high, and I am not sure about the mixture.....but other than that It seems to run great.

I've been driving 55 on the freeway. I drive combined city and freeway. And I have been using the engine off pulse and glide when I can.

A high idle will cause decreased fuel economy. Higher RPM's = more gas.

An air/fuel gauge can help you set the mixture properly. Narrowbands re cheap but are not as accurate as widebands. A wideband will cost you at least 160$ used on Ebay.

Also, can you set the timing? I am assuming you can, is it set correctly?

I never tried the pulstar plugs on my cvcc engine but my other Honda did not like them and it caused the engine to run poorly and a slight drop in mileage, copper core NGK V-power plugs have always worked best for me in Honda's, I've tried iridium tipped, platinum tipped and have a drawer full of plugs that saw 2-3 tanks of gas.
Stock exhaust, if it's over sized it will make your mileage drop, even more so with this engine, it's all in the math of pulsating flow.
If you can do a compression test with a warm engine and check your valves with a cool engine (50-90F) I've only seen a few that were in poor shape, but when they do have compression issues it will hurt things bad.
Tires! to wide is common and is not good, I think stock tire size is 155/80R13 and pump them up.
Is your engine warming up fully? if not then the carb adjusts to run richer.
Is your warm air intake intact and working? if not it will dump more fuel in to keep the engine from over heating and burning it's self up.
If one of the vacuum hoses is missing or cracked and leaking it will also cause the engine to run poorly and often burn more fuel.
You might also try running premium gas in it for the next few tanks as the cvcc engine doesn't always agree with the fillers, like alcohol that are in cheaper gas.
If you need any tune up specs let me know, I have a shop manual that covers the 1981 civic sitting on my book shelf.

I have the factory service manual and am researching how to adjust the idle. problem is... they say I need a propane enrichment kit to adjust idle and mixture properly. (anyone know where to find one)
I will have to try the air/fuel gauge.....

I checked the timing and it is spot on.

-I did try Champion coppers.....and Ii may have had slightly better FE with those, but I don't have enough conclusive evidence one way or another.
-The exhaust is completely stock, no mods whatsoever.
-I haven't done a compression check yet....will try to get ahold of a friend who has a kit i can use.
-The tires are the stock 155/80R13
-The engine warms up fully when I let it idle to get up to temperature, radiator fan turns on at appropriate temp too.(Once I start driving it, it drops back down again). However, when I am driving around, I rarely see it get up to operating range (or above 1/4 on temp gauge), or when I do it can take up to 15 minutes (or longer on cold mornings). I may check to see whether there is a thermostat in it.
-The warm air intake seems to be working correctly, the metal snorkel pipe that goes between the two is ok (cant think of the name of it), and the vacuum operated door in the iintake tube works fine. I already replaced the main intake snorkel as the old one had deteriorated.
-The vacuum hoses looked fine, but then again I may have missed something being as it is a 30 yr old car and rubber gets old.

I would imagine with only 62k original miles, there wouldnt be much that could go bad.

- I have a original factory service manual as well.

Ryland--

I was wondering what FE did you get with your Honda CVCC, and what was it in? I am just trying to figure out what to expect and what Ii should be getting.....I know these engines have the potential to be very efficient.