Shooting for 35 mpg

[HemiX2]

You're sure right about a bad/disconnected O2 Sensor killing the FE. You can also get the same FE loss with an exhaust leak before the upstream sensor. On a recent long trip I blew a header flange gasket and took a 3-5 mpg hit. The added air introduced into the exhaust, and picked up (sensed) by the O2 Sensor, would send a lean signal to the PCM and tell it richen up the mixture. I couldn't find anyone willing to fix the problem (real tight fit) so I ended up having to drive it ~1500 miles that way.

[drmiller100]

HHO is a frigging joke. absolute crap.

better off to save your money and hang magnets on the air filter to align the air molecules.

advance the timing until it pings, then back it off a bit. sounds like you are already there.

[3gd16]

I wanna try the hho cause i got everthing free from work as for the timmung it starts to ping when i try to get the dizzy in the center

[pete c]

HHO is snake oil. Just because you are getting it free, doesn't mean you should do it. Don't waste your time.

Beautiful car, BTW.

[3gd16]

Originally Posted by pete c

HHO is snake oil. Just because you are getting it free, doesn't mean you should do it. Don't waste your time.

Beautiful car, BTW.

Thanx

[3gd16]

Dam ran doesn't let me work on the car maybe tomorrow i'll reconnect the o2 sensor

[3gd16]

I haven't done nothing to the car yet to busy with work my highest mpg has been 28 but lost some with driving with the windows down and going up really steep hills on my last fuel tank that i drove 2 hours to my parents house. On Monday i'm getting new shocks and bushings replaced by yours truly and will be lowering it a bit. As for the o2 sensor it is still disconnected and will try to get it back and running when i change the shocks, after that i will get an alignment cause that is also killing my mpg and my tires too, they have only 5 months of used and they need to be either rotated or replaced. Will update on Monday if all goes well with the shock install

[tortillasoup]

I own a 1991 Honda Accord 4 Speed Automatic and I average 32mpg while cruising at 70mph on the freeway. Your car should definitely be doing better than what you're currently getting. I would stop replacing your o2 sensors and instead clean up the electrical grounds in your engine bay. Get a multimeter, and measure the ohms, if it's reporting more than 0 ohms, then you should clean up your grounds. I did this to my car and gained a few mpgs. Other thing you can do is run a fuel system cleaner through the car like chevron techron fuel system cleaner. Also if you have any check engine lights like for your EGR or whatnot, that too can cause the poor fuel economy. Always diagnose all check engine codes.

[3gd16]

Originally Posted by tortillasoup

I own a 1991 Honda Accord 4 Speed Automatic and I average 32mpg while cruising at 70mph on the freeway. Your car should definitely be doing better than what you're currently getting. I would stop replacing your o2 sensors and instead clean up the electrical grounds in your engine bay. Get a multimeter, and measure the ohms, if it's reporting more than 0 ohms, then you should clean up your grounds. I did this to my car and gained a few mpgs. Other thing you can do is run a fuel system cleaner through the car like chevron techron fuel system cleaner. Also if you have any check engine lights like for your EGR or whatnot, that too can cause the poor fuel economy. Always diagnose all check engine codes.

Thanks i wish i could average that but the max i could get was 28 so it will need a little work done so i can get to my desired mpg, the only code i get from my check engine light is from the o2 disconnected. Is yours also a wagon? Did you remove your egr?

[tortillasoup]

Originally Posted by 3gd16

Thanks i wish i could average that but the max i could get was 28 so it will need a little work done so i can get to my desired mpg, the only code i get from my check engine light is from the o2 disconnected. Is yours also a wagon? Did you remove your egr?

So why don't you just re-hookup your o2 sensor then? Other thing you should do is reset the computer by disconnecting the battery for like 15 minutes so the computer can re-learn some of its functions. Also, you shouldn't have to remove the catalytic converter from the car for it to get good fuel economy. If your car has two o2 sensors, and the cat is removed, that too can affect fuel economy since the car uses the second o2 sensor for fine-tuning the fuel trims. When you're checking the grounds, be sure to measure from the point of interest to the battery negative terminal. To eliminate the most obvious point, be sure to clean up the battery ground strap, its nuts, bolts, washers, eyelits, etc, don't scrape any paint off but make sure the holes it bolts into are free of dirt or rust. From there you can get a better idea with the multimeter of how good or bad your ground resistance is. 1 ohm of resistance is 1 ohm too many!

I should mention that you should get your car back to stock as best as you can. After re-reading some of your posts, I realize that you have too many things on the car that aren't stock like the wrong distributor and whatnot. You should never have to advance the distributor too far in any one direction otherwise it potentially prevents the computer from doing its job of adjusting ignition timing properly. If you could get everything in your car working 100% like stock, 32mpg should be within range. Have you tried replacing your PCV valve? That's an easy fix on this car and its replacement can boost fuel economy by about 15% if it's clogged. Or how about clean the throttle body/idle control valve? Is your car idling at stock RPM with stock ignition timing degrees? I bet it isn't! All the check engine codes have to be gone if you expect to have your car perform optimally.