cephalo

1982 Honda Accord Automatic, Hatchback. 1.8L CVCC 2nd generation I believe.

I'm trying to figure out why I'm getting 16 miles to the gallon.

But first, I have to give you some crazy history. For a couple of years, my car has been smoking pretty bad, and at the time I didn't know all that much about cars so all I did about it was use that anti-smoke gunk in the oil. I always had a feeling that my car didn't get the gas mileage that it should have, but I never really tested it, not really knowing what I could do about it in any case.

Around Xmas time, the problem showed itself more drastically and forced me to become intimately familiar with my Honda. The holder nut in my number 2 auxiliary valve worked itself loose and started rattling up and down. Apparantly it had been approaching this state for a long time, and the oil seal around the valve was broken from being allowed to move around in it's socket. This was the cause for all that smoke. Oil was leaking into my no. 2 cylinder.

I replaced the oil seal and got it all back in there. In order to get good access to screwing this valve holder back in place, I had to take the camshaft out, and while doing so I didn't put the engine at TDC, so when time came to put it all back together, I had to figure out where to put the cam timing.

This is where things got kindof confusing, because my Haynes manual's pictures and markings had nothing to do with my car, it was all different. Anyway, I made my best guess, and I rotated the engine by hand to see if I had any resistence from the vavles being in the wrong place to ensure that I wasn't going to ruin my valves. I put everything back together, followed the ignition timing procedure in my haynes manual (it was wrong, more on that later) and the car seemed to run fine. The only problem I could eventually detect was that I was getting 12 miles to the gallon. Even though my gas mileage was always kinda funky, it was never this bad.

So I went to the public library because I knew they had lots of service manuals there, and I looked at the Chilton and Mitchell manuals, the big ones with all the makes and models in it by year. The description of the cam timing marks were all different from edition to edition! One of them said that you need a different setting for CVCC engines than for non-CVCC and I followed those instructions. My gas mileage actually improved to 16 mpg, but the car would sputter while going uphill and get really hot on the highway.

With all this conflicting info on how to set my cam timing, I found a used copy of the official 1982 accord repair manual and I think I found the source of the confusion. There is a procedure for taking off the timing belt while the car is not TDC to prevent the engine pressure from moving the camshaft when the belt is off. You line up the markings with an arrow on the cylinder head. But when you have the car in TDC the marks have to be pointing to the top of the head. Aligning the marks to the top of the cylinder head solved most of my problems.

Also, for the ignition timing there is further confusion. My haynes manual says that you must disconnect the vacuum hose from the distributor, while other manuals say explicitly to leave the hoses connected, while the official manual omits any mention of the vacuum hoses in the timing procedure. Through intense expirimentation, I have found that if I disconnect the vacuum hose and line up my TDC mark(not the timing mark) with my timing strobe, and then plug the vacuum hose back in, the timing advances exactly up to the RED timing mark labeled 16 degrees. That makes me think that I should line up the RED mark with the vacuum hose CONNECTED.

According to my best sources, I now have the cam timing and the ignition timing set up correctly, I hope.

All is not well however. I still get 16 mpg. Also, even though my exhaust is no longer smokey, I can see through the sparkplug hole that theres still a ton of crap in there and I have to replace the no. 2 spark fairly often because it fouls out. Since I'm not sure what my gas mileage was before all this happened I'm not even sure if my problem is related to the engine timing. I checked the compression on all my cylinders and they are all the same and fine. During this whole process I have been guided by friends who have alot of experience with cars, and they are stumped as to why my gas mileage could be so bad.

What else can I look at?




Modified by cephalo at 9:04 AM 6/21/2007