Horrible mpg vx 17mp

[VX.hatch]

This should be the last unnecessary post. sorry

[VX.hatch]

Here's my youtube channel link with some videos that I hope will provide insight and diagnose the problem. http://www.youtube.com/channel/UC-QSS_OQ3FP6eAf_6uZCmwQ

[FiShNc]

Wow! That's not just an MPG issue. Something is very wrong there, and bad mpg is probably only a side-effect. I'd suggest you repost or get the thread moved to off-topic tech. Change the title too. I suspect the people looking to help with problems like this are more likely to be looking in off topic tech than ecomodding central. I'm sure you've already tried Honda tech and Honda swap.

[VX.hatch]

Not yet. I forgot my username and password but I'm planning to post wherever I can. The problem is getting worse and worse, not good.

[Ryland]

At least the stock VX engine will not run right with an over sized exhaust and over sized or leaky exhaust will destroy o2 sensors on the VX very quickly.
The engine sounds like the timing is off...

[VX.hatch]

Originally Posted by Ryland

At least the stock VX engine will not run right with an over sized exhaust and over sized or leaky exhaust will destroy o2 sensors on the VX very quickly.
The engine sounds like the timing is off...

I read that to but My O2 is still good as it runs worse with it unplugged. I checked the timing with a timing light and I zeroed it out, white line on crank pulley. I figure even with the leak big exhaust if should still get better than 12 mpg like in the vid.

My mpg's have gone down to 12mpg as of yesterday. First time out the engine started at 28mpg, 2 weeks ago, then 17mpg last week, and if my math is correct 12mpg as in the video. What could cause this dramatic and quick decline in mpg.

[hamsterpower]

Have you checked the injectors? If they are stuck open it could be dumping way too much fuel.

[user removed]

Pull the plugs and look at them. If they are equally dark then you probably have a fuel pressure regulation problem, or a leaking diaphragm in you pressure regulator. Another issue could be cam timing and that would affect your timing settings. Also check compression while you have the plugs out. If your compression is good and cam timing is good, then I would check fuel pressure.
Once you have those items sorted out you should be getting decent mileage.
Also check alignment and check for dragging brakes. How does the car coast? That would give you an indication of higher rolling resistance due to tire pressure, brake drag, or seriosu misalignment of the wheels.
You can do a crude alignment check by sighting down the front tires to see how close they are in alignment with the rear tires and vice versa.

regards
Mech

[FiShNc]

There are a tdc mark and timing marks. If you're sure the timing belt is on correctly and lined up with the correct marks, you might verify the distributor is TD42U. It probably is but worth checking.

About the injectors, it seems you're definitely running rich, but that isn't the only problem. Regardless, I'd recommend running a few tanks with Techron concentrate or Redline SI-1 after you get the fuel correct. Running so rich for so long can increase gum and varnish buildup on your intake and valves.

I can help you diagnose if your injectors are stuck open if you can get an oscilloscope on the ground side and show me the waveforms.

Also be careful you don't melt your cat. All that extra fuel can get it way too hot.

[Ryland]

Originally Posted by VX.hatch

I checked the timing with a timing light and I zeroed it out, white line on crank pulley.

Your ignition timing can be correct while your cam shaft timing is off by a full tooth, on my first civic vx the mechanic that changed the timing belt lined the cam shaft pulley up with the top of the head and not the small timing arrows that are cast in to the head, it still ran, the ignition timing was correct but it was gutless.