I just re read my engine codes (93 5.0) and got a hard code of 22(MAP) and a memory code of 41(system lean). Could mt MAP be hooped? I don't think I can check my MAP as I do not have a tach to do this. My Haynes manual sez Maps are either voltage or frequency varying types and the later ones are the freq type. What constitutes "later"? Any sugestions? SR.

 

Before you go to far, make sure the vacuum line and nipple at the manifold for the MAP is not partially blocked with carbon. Also, make sure the hose is at the correct nipple on the manifold according to the decal...you'ld be surprised. I beleive most MAP sensors work on voltage and all MAF sensors work on frequency, but I could be wrong.
Phil

 

Also be sure that you are getting a code 22, and not a repeating code 11 (system pass/OK). It's real easy to confuse the two. I did and needlessly chased after a suspected bad MAP sensor until I figured out I was getting a code 11 repeat instead of a code 22.

 

Thanks for the reply. It must be that I am getting the 11 code instead of the 22. The light flashed 2 times then a pause the 2 times again then a long pause then a flash followed by a long pause then the memory code of 4 flashes, pause then 1 flash pause, 4 then one again which I am led to believe is a 41 code, system lean. The truck runs fine and is getting typical milage in spite of the cold weather and slower driving, sometimes in 4wd due to snow. So now I will sleep at night knowing that my trucks computor is telling me that "all is well"and after all, computors never lie do they? I know the tax deptments don't!!

 

 

i just pulled a code 41 (system lean)yesterday. this truck has gone through 3 catalytic converters since i bought it new. where should i start troubleshooting? fpr? fuel filter? thanks.

ric
91 f250s/c 7.5L w/89k miles,banks power pak

 

I have blocked my EGR valve off so I think this is what is giving me the 41 code most likely caused by the smog pump. Maybe I will try a shorter belt to eliminate the pump although the engine seems to run just fine with the exception of a rough idle which I can live with.

As for troubleshooting the code, it is the O2 sensor that is telling the computor that that there is a lean condition but what is causing this condition? Have you altered the engine in any way, such as a restrictor/blocking plate in the EGR? If not the O2 sensor may be out of range but you would get a code for that. Take the truck for a good hard run then shift into neutral and brake to a stop, if you have a place where you can do this safely, shut the engine off too. Pull a couple of spark plugs after you stop (be carefull their hot) and look at the colour of the ceramic insulator, it should be a light coffee colour, any lighter than this would indicate that it could be running lean. If this is the case there is a reason for it and this would be your next course of action. Think like a computor. What will cause you to say "I'm lean"? Bad injectors? Bad fuel regulator? weak fuel pump? If any of the sensors are out of sort the computor should(Note that I said "should", it is a computor after all) send a code telling you which one it is, such as MAP or TPS etc.

I hope this is of some help in your quest for a better running Ford.