codes codes codes......???

[ducksplus]

I have codes
koeo 11
cm 41... lean right
koer 42...rich right
cel comes on about 15 minutes after running and usually stays on until i shut the truck off.. then at next start its off until about 15 minutes.. also its kinda hard to start... it just about 4 seconds to start.. that dont seem long but it kinda is..:???

i replaced the o2 sensor.. cleaned maf..so i dont understand how it say its always lean and always rich... what is my next move in trying to fix my 91 x.
its only getting 10mpg....ouch!

 

[Glacier991]

how is your fuel pressure ? Might investigate the FPR....

 

[MrShorty]

Did you clear the CM codes after the mentioned repairs to make sure CM 41 is a current problem? Did you get the spark plug wires replaced?

Assuming the new O2 sensor is good, the things to check are fuel pressure and check the wiring between the sensor and the computer, and check the computer's grounds.

 

[ducksplus]

i cleared the codes and cm 41 is still a problem.. i havent changed the wires yet but soon.. i dont know much about the wiring of the motor.. i dont really know where to start on checking that.. how would i check the cpu ground?? But i got a differnd fpr and im replacing it this week.. maybe that will do some good..
Mike

 

[MrShorty]

FPR might help if it is the problem. You really won't know unless you put a fuel pressure gauge on it and see.
As for checking the wiring, 1st step is to get a wiring diagram, then make sure you have a basic understanding of DC electricity. Then put a voltmeter across the ground wires and see if there's a significant voltage drop across the ground wires.
It would be interesting to put a voltmeter on the O2 sensor and see what it's outputting.

 

[ducksplus]

whats the voltage on the o2 sensor suspost to be??
and how do i relieve the pressure on my fuel line that runs to the fpr so i can change it out.. is their a fuse i can pull to stop the pump from running???

Mike

 

[MrShorty]

"Ideal" value is 0.45 V. The sensor signal should cycle continuously from below this value to above this value, always within the range of 0-1 V. A 41 code is triggered when the sensor never goes above 0.45 V. A 42 is when the sensor gets stuck above 0.45 V.

Like 410fortune said in your other thread, disable the fuel pump (either pull the fuse, or unplug the inertia switch) and let the engine die.

 

[ducksplus]

MrShorty
changed fpr and finally got all pass codes...
FINALLY>>
now maybe ill get better mpg.. rather than the 10 mpg im use to...
mike