I got the directions from fordfuelinjection.com
Not confused with the direction as they are simple to follow....BUT here is what I got.

- is one sec pause

Key On Engine Off ...........................CM
<glitch> 1-- 1-- 1 ---- 1-- 1-- 1 ------ 1 ---- 1-- 7-- 3 ---- 1 --7 --3

KOER = Key On Engine On
3 (but that is all that happened. three quick blinks)

Any ideas. looks like 111 = good but 173?? or the 3??</glitch>

 

Code 173 looks like you read it right (at some point the O2 sensor read rich). Do you have a six cylinder? I'm guessing the 3 blinks was the engine code. I have always had codes during the engine running test, so I'm not sure what it does when there are no codes.

 

The 173 is coming from continuous memory. The code stands for "lack of HEGO switches, indicates rich". Your oxygen sensor is telling the computer, during normal operation, that the mixture is always too rich. This at a time it should be switching back and forth from slightly too lean to slightly too rich.

Usual reason for this is a dead oxygen sensor, too high fuel pressure, failed fuel pressure regulator, or leaking injector. The dead sensor will cause code 173, but the engine will be running way too lean as the computer runs the mixture adjustment all the way lean trying to provoke a reaction from the oxygen sensor. The other possibilities would all go with an engine that really is too rich.

The 3 flashes early on in the KOER test mean that you have a 6 cylinder engine. When you see the 3 flashes, you should step on the brake, turn the wheel left and right, and cycle the O/D cancel switch a couple of times. In the meantime the computer will be running the KOER test, which takes on the order of one minute. At the end of this period, there will be a single flash, which is your cue to stomp the accellerator pedal. The test ends about 10 seconds after that; your codes will be produced at that point.

 

Thank you both.
Yes, I have a 6 cylinder.

Should I start with the O2 sensor and see what happens?
When I stomp the accellerator do I hold it down?

 

Don't hold the throttle down - push it quickly to the floor and then release.

 

It is wasteful to replace parts based on one instance of a continuous memory code.

Get the the KOER test to run all the way through, with the engine warmed up. This will test the oxygen sensor, among other things. If the test consistently produces code 173, or something similar, and the oxygen sensor has a lot of miles on it anyway, then you could consider replacing it. There are ways to test it with a voltmeter instead of getting out the parts shotgun....

If the KOER test passes without codes, clear out the continuous memory codes and drive the truck for a day or so. Check the codes again. If it sets code 173 after one day of driving, then consider replacing the sensor.

You should also consider how the engine is running. Is it too rich, too lean, or does it seem to be OK? The oxygen sensor may be fine; but the truck is overfueled for one reason or another.

 

I have been having miss firing underload during which I saw the check engine come on (Once).
Last night I replaced all the plugs as i did fuel filter,wires,cap and rotor two weeks ago.
I just got the truck 3 weeks ago so i like to do all this anyway.
I will clear the codes and see how things go.

THANK YOU for the engine runnoing directions. I will do that later this morning after I drive to work.