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Old 05-12-2010, 02:55 PM   #9 (permalink)
EcoModding Lurker
Join Date: Apr 2010
Location: Far Northern California
Posts: 13

Outback Sport - '08 Subaru Impreza Outback Sport
90 day: 25.84 mpg (US)
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Originally Posted by Ryland View Post
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 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.
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