running too rich, why

[89saleen388]

89 5.0


after i replaced my exhaust with an off road x pipe, i seem to be running way to rich.....gas mileage is way down and my rear bumper is covered in black carbon.....why????

of course with no cats stronger exhaust, but this is straight carbon and an 8 mpg drop...any help is most appreciated

[stang_racer20]

I'd be willing to bet you accidentally damaged your O2 sensors in the swap. Try pulling codes and post back.

[LX5liter]

Originally posted by stang_racer20
I'd be willing to bet you accidentally damaged your O2 sensors in the swap. Try pulling codes and post back.

Either that or they weren't plugged back in or the connections are bad.

[89saleen388]

thanks for the replies, i finally pulled the codes and i got a bunch

with the key in on position i got :67 29 31 95

with the car running i only got one code : 21

can anyone help me with what these codes mean and if they have anything to do with the o2 sensors or why i might be running so rich, thanks

the o2 sensors are plugged in

i recently had the fuel pump replaced so that might be some of the codes.

thanks a lot for the help

[crazypete]

The code 21 is because you ran the test with the engine cold.

The code 29 is telling you the vehicle speed sensor is out of wack. You probably wacked the side of the transmission installing the exhaust. I think the VSS is at the end of the speedo cable.

The code 31 is telling you EVP/PFE signal is low(??)

The code 67 is saying the neutral saftey switch has failed at some point. You probably nudged it installing the exhaust.

and the code 95 is saying your fuelpump circuit is bad. This was from you install.

Clear the codes by unplugging the battery for 10 minutes and then drive it around for a day (it will run like crap for 10-20 minutes while the computer relearns the car). Then see what codes you pull.

Go here http://www.dalidesign.com/hbook/2digit.html
A list of codes and what they mean.

Good luck!

[89saleen388]

hey thanks for all the help, and that link

i disconnected the battery for a while then drove it for a while and then pulled the codes again..


key on i got : 67, long pause 1 long pause 31

running all i got was 11

should i just replace the o2 sensors??????
if i replace the o2 sensors and it does not improve things, what should i look into next

thanks for your help

[crazypete]

if it says running is 11, then there is no standing condition in the motor, hence you should not be running rich at all. The code's 31 means that the sensor on the back of the EGR drum is bad. I would replace it since it's not that expensive. The code 67 is meaningless since you got the engine started then the neutral saftey circuit shouldnt bother you.

Technically, you should be running a bit leaner if anything from the extra airflow due to lower exhaust backpressure if the EEC could not compensate. I leaned out when I installed my x-pipe.