hey guys i have a 1991 honda crx si and im having a little trouble will the gas, i filled up my tank and drove about 56 miles and i already have a little less then half a tank. i dont know what my problem could be?car is running really rich because you can see and smell the gas from the exhaust pipe.car doesnt have a 02 sensor dont know if it could be that? and also owner before toke off all the vaccum system with the map?Thats problem one, problem two is when i rev up the motor slowly at a stop, car starts breaking up, but only if you rev it up slowly, kinda sounds like a two step but its not?

 

yeah you are definitely running rich, and your ecu doesn't know it because you have no o2 sensor.

get that right and go from there

 

spark plugs

 

just put brand new plugs in

 

i might also be your timing

 

also check ur dizzy and maybe larger fuel injectors and any of those things are a good idea

 

Do you not even have a MAP sensor installed? How does it idle? No MAP sensor plus no O2 sensor are your main gas guzzling problems.

 

give it a tune up and put a map sensor back on it.....how does it even run???

 

Possibly also a stuck injector (though unlikely). That would make it a hard start.

 

So, if I've been able to correctly decipher what you've written, you have no O2 sensor and a disconnected map sensor/messed up vacuum system?

These two problems would be a very good place to start. Typically when you know about a problem with your car AND it isn't running properly, it's a good idea to fix the known problem(s). I would get a stock vacuum diagram, fix your vacuum lines and then connect your O2 sensor. I imagine that you have a header without an O2 bung (this is the only option that makes sense anyway) but even if you're too cheap to get one welded in, I suspect that fixing the vacuum system will be a big improvement.

Edit: Oh, and some of the responses are unreal... sparkplugs because you're running too rich? Distributer? Larger fuel injectors??? Come on...