just bought a 98 f150 5.4 with the ford motorsport centrifigal supercharger and having issues. had a p0153 code in it which means slow o2 sensor response/running lean from bank 2 posistion 1 as i understood it. i replaced the sensor and checked the wiring, i also cleaned the mass air meter checked all my intake connections and replaced the fuel filter. i cleared the computer and the check engine light is off as of now but still idles like crap and stumbles baddley below 1800 rpm. it seems to run and idle fine until it's warmed up and then the problem starts. what the hell is wrong with my truck, please help!!

i aslo noticed that the inlet side of the idle air control motor is plummed into the discharge side of the compressor, is this right? should it be before the supercharger but after the meter. i dont have any history on the truck i bought from a small hole in the wall dealer. thanks in advance.

 

What is the hisory of the SC?
Was it added, is the PCM program modified for SC use?
Sounds like the motor is really running lean due to tunning/hardware reasons.
If the SC was added, there is a host of things that need to be correct to prevent engine issues.
Your discription of the drivability is what happens with a lean condition.
The OX sensor is a warning telling you the A/F ratio may be to lean.
When the motor is cold, the PCM richens the fuel until the OX sensors heat and begin to control the fuel, then the fuel leans out to normal.
The SC is forcing more air into the motor so needs more fuel.
Only way is to have a program change to make this happen.
For that you need a specialized tuning shop.
Running lean rather than rich invites burned pistons, pinging etc if you get on the power to much.
I have only offered a general overview of running an aftermarket SC setup and some of the items you need to be awhere of.
Good luck.

 

i dont have any history on the truck. it's the motorsport/powerdyne unit. i can tell that the injectors are 24lbs units and the air meter looks to be a lightning unit. i still haven't checked the fuel pressure yet. if it was running to lean wouldn't it run worse under boost? above 2000 rpm or so it pulls hard with no pinging. maybe a stuck fmu and to much fuel pressure until boost? thanks for the reply.

 

I can't really help you but the fuel curve needs to be taylored to the blower as well as the ignition advance in all speed ranges and loads.
This is where you need to know what was done with the installation or go to a custom tuner shop experienced with Ford blower applications to sort it out on the dyno and make the software/ hardware changes, if needed.
The 24lb injectors may not be large enough unless they were a known part of the blower package.
A question is is there a larger fuel pump in the tank?
This is for volume flow and not just pressure.
It may be a fault or a tune issue, don't know.
Power is always a nice feel under foot.
I have had a Kenne Bell blown small block 5L and loved the huge torque it made down low.
Good luck.