Running Rich

[eric99gt]

This is for a beater 93 intrepid that I have with the 3.3. Car is running extremely rich. Gets about 10 mpg and spits out black smoke like no tommorrow. Colors the ground black in seconds. Odd thing is though it feels like it's running perfect. No misses or anything like that. Changed the O2 sensor and that didn't seem to fix the problem. I did notice though that when I unplugged the sensor that it didn't change the way the car ran or throw a code so I figured something might be up with the sensor. Didn't seem to help. Any ideas?

[eric99gt]

anyone???

[HeyDace]

I had a '94. Check for vacuum leaks first. And if I remember correctly a bad map sensor is common on them. Fuel and oil migrate into the sensor and contaminate it. Not saying that is the prob, but a possibility.

[iceman]

is there more than one sensor (pre-cat) ?

[eric99gt]

Only one at the manifold.

[rixGAphx]

I don't know squat about the Chryco 3.3, except that the '93 would be an OBD-I (or similar) crude computer operating the FI and ignition.

The O2 sensor *should* tell the computer to clean-up its act.

The only thing that would prevent it from doing so would be excessive fuel pressure.
No matter how short the ECM makes the injection pulses, the injectors will squirt a LOT of fuel if the pressure is too high.

Nearly every FI system has a pump that produces significant pressure (about 60 psi), and a Fuel Pressure Regulator (FPR, usually on the fuel rail) that REDUCES the pressure to the 'design pressure' (usually about 43 psi) by bleeding-off pressure.

Check the FPR, or just throw-on a new one considering the current one's age and the relatively-low cost of a new one ($40 for a GA FPR, dunno for a Chryco).

Hope this helps,
-Rick

[eric99gt]

I'll give that a shot. Thanks rick. I was hoping you would chime in.