Well, I thought I'd change the plugs and see if that does anything:
old fouled spark plugs
and replace them with some NGK Platinums ( NGK BKR5EGP ):
new and old spark plugs
Installed with anti-seize on the plug threads, torqued to 20.5 ft-lbs. and dielectric grease in the spark plug boots. The spark plug wires looked pretty new (blue NGK wires).
We'll see if changes anything in the mileage dept., but it looks like things are just too rich, but that's maybe that was mostly the choke being on. After I get the mpg again, I might try the mechanic-in-a-can (seafoam added to the oil) to clean the oil rings like dlb suggested to me earlier (and of course an oil change like mark says // it looks like I'm pulling the dipstick on a diesel it is so black).
I am curious, but nervous to try seafoam. Does it work? Or possibly loosen up big pieces of carbon. My daily driver is burning oil and I was thinking of doing an oil treatment to buy some time before I rebuild an engine for it. I would like some of your feedback.
marlinh, my wife's '92 civic vx was burning hellish amounts of oil. like, if i used engine braking going downhill and then stomped on the throttle at the bottom, it would billow blue smoke so thick that i couldn't see behind me and it would last for about 5 seconds, maybe more. after yakking about it on here i took keith's advice and added seafoam to the oil. i ran it for maybe two tanks of gas before changing the oil, and now the car only gives the occasional small puff of blue smoke on start up but never after engine braking or regular driving, and i only need to add a 250-500 ml of oil every 2 or 3 tanks. i was really impressed. i can't really comment on seafoam's usefulness in other applications but for carbon'd up rings, it did wonders for me.
Reporting back that after changing plugs there is still a weird missing happening under load. It seems a bit less than before though. The tachometer also is affected (flicks up and down about 200 rpm when missing), but it seemed to also be affected more before I changed the plugs. Maybe I ought to look at the cap and rotor before I go for the seafoam.
dlb, did you follow the instructions and add 1 1/2 oz per qt of oil for the flush. Did you use it after an oil change or just before? Been reading some comments on other sites and some reviews are not too positive.
seafoam will not fix a electrical engine miss, I do not even think a bad cap or wires would cause the tach to jump, might be bad contact, or bad pick-up in the distributor. do the tests in the FSM for the various components and check all connections in the distributor and connectors.
plugs do look rich, a bad miss will cause that but not an occasional one. Of course running really rich can give a miss too, but it will not affect the tack, that sounds like it is electrical. But check for rich condition by checking your AAP diaphragm (pull the vac line and see if it is full of gasoline), you can cap it off as a temp fix, it will run fine without out it(only is used to help acceleration when engine is cold). Also check that choke is opening all the way. there are instructions and procedures for both of these repairs on this forum and in the FSM.
yup, i followed the instructions on how much seafoam to add to the oil, and i did it just before an oil change. i figure once you start breaking all that sludge down, probably best to change the oil and filter to get it all out.
