116Clique

ok, i have my 89 Gt and it is running very rich. Mod that maybe the culprit is the long tube headers. I am pulling code 44 and 94 related to the O2 sensors. What are my options to getting the car the run correctly. I can smell fumes sometimes as i'm driving and MPG is worse than expected for the few mods on it so far. Any other threads i can check out or advise would be great.

thanks.

Five0hFox

My car was running so rich that's was smoking black. Turned out to be a stuck injector.

mattdel

Try this:
https://mustangforums.com/forum/5-0l...l.html#2355308

116Clique

Mattdel,
So you think that it could be the ECT Sensor and not the O2 sensors misreading the cylinders?

mustangGT86_05

O2 sensors will throw codes for detecting an excessively lean or rich condition, not just because they are faulty. Also, the only way the headers would cause it is if they were not sealed properly, the o2 sensors would see added air and throw more fuel to compensate. So my question would be is your o2 sensor code saying lean, rich, or a circuit failure?

mattdel

44 and 94 together usually mean that the entire system is leaned out. Seeing them together almost surely eliminates them as the cause. Lots of reasons for these codes to pop up.

ECT
Fuel pump
Clogged injectors/fuel filter
Intake leak (tube/gaskets)
Exhaust leak (before the o2's)

Each time we see these codes, it ends up being something different, but its not the oxygen sensors.

116Clique

ECT- Plan to check this just as your other thread said to. need to get a new multimeter. perhaps ill just pick a new ECT.
Fuel pump- Planning to order a new one very soon(Any considerations for a very mildly modded mustang?) my sending unit is also making the fuel guage display incorrectly.
Clogged injectors/fuel filter- ill have to work on this one
Intake leak (tube/gaskets)- truthfully not sure
Exhaust leak (before the o2's)-hearing a small leak on the pass side in the vicinity of headers/heads link.

My car is also having a hard time starting: the voltage reads normal while running, but prior to start while on ACC. the voltage reads in the red. all this to say its a great time to ride the CBR and work on the car. all help is much appreciated.