Ok, ever since I swapped my 305 tbi to a 350 tbi, my car has been running really really rich, and when I say really rich, I mean sitting at idle smelling like gas, sitting at a stop light, i pretty much wear gasoline colgne... I dont have any gas leaks that i can find, and I dont believe I have any... My tailpipes are black as night. I swapped my comp, knock sensor, injectors and prom... I did re wire up my O2 right where I took my cat off. Uh, I havent tapped into my fuel lines to test my fuel pressure... I never really changed the ESC (Electronic spark control) Could that have anything to do with it? I know that the ESC is supposed to partner with the knock sensor, and since I changed the knock sensor could that be anything to do with it? Maybe even a bad O2? I am completely stumped, and have been for months... My car gets 6 mpg and has for a while since I changed out the motor and apparently, I am sick of it and want to try to finally figure this S.O.B. out lol

 

sounds like it could be an bad O2, i dont have a cat on mine and dont have that problem, but i have somewhat of a un burnt fuel smell as does any car/truck without a cat

["I did re wire up my O2 right where I took my cat off"]

Maybe your O2 is to far down stream for it to heat up properly, you need to have it near or in your collecter, O2's need to be close to the head to read properly.....i would go that route i think, and swap it out for a 3 wire

 

Thats what I have been thinking... Because I know they have to get like 365 degrees before it starts to even do anything and I am not quite sure it gets that hot directly under the passenger door on the pipes

 

If you put your O2 down where your cat was, it is way to far down the pipe. If you were to straighten that pipe out, your O2 would either be sitting next to the crossmember or the tailshaft.

Stick it back into your collector where it should be.

 

yea thats what i was thinking, but i was a little confused on what you were saying on it location, i would go with a 3 wire when you replace, and strangely a universal 3 wire is normaly cheaper than you stock replacement

 

How much of a chance do you think this will actually fix my rich running problem? I can't do anything about re-running it right now, I have to go to work in a bit, and right now its rainy and cold so that sucks... Maybe next week sometime

 

AT FIRST, you will not see a large change unless you unhook the battery to erase the BLM (ecm memory). The ECM has to learn of the change back to the correct location/correct ability to read the O2 sensor at part throttle. Once that occurs, you will see a large difference at part throttle. Right now your ECM is feeding the injectors and the dizzy programming for open loop mode because it has no way to know what the O2 is doing.

You should not be getting 6mpg. That's large cam and tons of mods mpg.

 

No really... I literally get 6mpg... Its almost as if my car is dumping gas out the pipes

 

That's what I was saying. I wasn't debating with you. I said you should not be getting 6 mpg. I didn't say you weren't lol. And you are dumping fuel out the pipes. It has no way to burn it so it's sending it out unburnt.

Move the 02 sensor back into the manifold/header collector.

 

Wait... Would I need to run two O2 sensors? Because someone told me that I have to have readings from both headers... That's why I put it so far back on my pipes. I put it where both my pipes met so I could get readings from both pipes

 

To be blunt, someone has no idea what they are talking about. At the same time, they do.


The factory system is made to only read the mixture from the driver's side bank (cylinders). The O2 sensor must be where the exhaust gas is the hottest and where it can see the full bank (all four cylinders). That area is the collector.


While it is true that two O2 sensors (one in each bank) will give you a better idea of what's going on, you cain't just wire in a second O2 to your factory system and get the results you are looking for.

You do not HAVE to have readings from both banks. No car read from both banks until OBDII systems were released. If you are that concerned, you can hook up an O2 monitor to the other bank and look at what is going on.

 

I would have to agree about the 02 sensor. its prolly always in open loop..

 

Well thank you all very much for your input... Very helpful information. I will try moving it to the drivers collector and see what that does me