Have a 5.4 that we can not seem to get this truck to set monitors. I am very familiar with the drive cycle. Vehicle is not running lean or rich. Fuel trim is very close to dead on. It will not set 02 heating, O2 sensor, Cat or Evap. I have worked on many of these fords, but this one really has me baffled. No codes anywere. We have replaced the following, front O2 sensors, Evap purge valve, air flow meter. Recently tune up due to misfire before trying to set monitors. Any ideas or suggestions would be greatly appreciated.

 

How long are you allowing for monitor resets?
The Ox sensors will take a couple short cycles.
The EVAP system testing is complex and can take many drive cycles or days to complete.
The Cat tests are seperate, looking at switch ratios to be within limits telling about the health of the Cats.
Look at the live data on the OX sensors for actions that are not normal like to slow etc..
My feeling is there could be a harness issue because the OX sensors and EVAP are in the same wiring going back to those locations.
Transmission control is also in with them but if no problem shifting then it can be out of the harness toward those locations.
Fuse 23 normally feeds all these functions in an F150.
Good luck. Let us know how it went.

 

I understand the complex of setting the monitors. When all is ok they will set very quickly. I have a drive cycle pattern I use on all Fords and they will set within 15 minutes, other than the EVAP. We can smog in California with one monitor not set. This vehicle belongs to a co-worker and I have driven this truck many times. Normally if the system does not set the O2 Heater it wont set the others. I can not get this thing to finish setting the monitors. We have about 45 of these trucks in my work fleet that we service. I have never had an issue this bad to set monitors. I am wondering if the cats are bad and causing this problem. I was thinking about have a pre test done to see were the numbers are at. Any ideas

 

Look at the rear Ox sensors for switching.
They should not be switching or moving at all if the Cats are within spec..
Good luck.

 

They are not switching, they stay steady at idle around .780 Volts. Both are close to each other. Under load or driving they go down to around .350 Volts.

 

Ok ,that pretty much rules out the Cats as the source of the issue.
The front Ox sensors don't care a thing about what the cats are doing behind them, otherwise.
I can't see how a monitor is not finishing if a fault has not been detected.
Is there any chance the KAM fuse/supply is open causing a reboot everytime the truck is started?
Otherwise no one would know there is a problem unless the code 1000 was seen on a Scanner and the monitors were not reset.
Good luck.

 

it is not rebooting. It does not loose its memory. The EGR monitor sets and it does not forget that it passed. Its all has to do with the O2s not setting.