I've been digging through posts for a week or so now but can't seem to find the correct answer to my problem. Decided to just sign up and ask 
MAP sensor keeps clogging
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MAP sensor keeps clogging
Have over 300k on our 1993 f150 5.0 engine. Recently it decided to start running extremely rich and stalling out. Bought a code reader and started replacing parts. Got them all to clear except a code 44 during KOER test. Truck was running best it has in years so didn't worry about it.
Around 70-80 miles later, truck starts running rich and dies again. Pull codes and 22 is back (bad MAP) Figuring I got a bad one, I replaced it and all was good again.
Few weeks later, probly 70-80 miles again, same problem. code 22. This time I blew it out with an air compressor and the code went away, engine runs fine again.
I'm guessing it must be something with the code 44 (Thermactor air system fault) Replaced the TAB/TAD but code 44 still there.
Any hints on why the MAP sensor keeps getting clogged and how to fix it would be greatly appreciated. Getting frustrating just throwing parts/money at it with no change
Around 70-80 miles later, truck starts running rich and dies again. Pull codes and 22 is back (bad MAP) Figuring I got a bad one, I replaced it and all was good again.
Few weeks later, probly 70-80 miles again, same problem. code 22. This time I blew it out with an air compressor and the code went away, engine runs fine again.
I'm guessing it must be something with the code 44 (Thermactor air system fault) Replaced the TAB/TAD but code 44 still there.
Any hints on why the MAP sensor keeps getting clogged and how to fix it would be greatly appreciated. Getting frustrating just throwing parts/money at it with no change
Fleet Owner
Joined: Aug 2005
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From: Easton,Ks
Thermactor air system only effects the exhaust system. You do not have an O2 sensor fault that would come from the Thermactor air system being bad.
In other words an O2 sensor would make it run rich but you do not have that code.
Other than that the MAP sensor can also make it run rich and if it does not get the right vacuum from the engine it will cause the MAP to cause it to run rich.
But you should not get anything up a vacuum hoses unless the engine is back firing back through the intake.
In other words an O2 sensor would make it run rich but you do not have that code.
Other than that the MAP sensor can also make it run rich and if it does not get the right vacuum from the engine it will cause the MAP to cause it to run rich.
But you should not get anything up a vacuum hoses unless the engine is back firing back through the intake.
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Hmmm...so it could be a vacuum leak somewhere causing the MAP sensor to make it run rich. But if that was the case, why would blowing it out with a compressor make the code 22 go away and it run smooth again for awhile?
I do see what your are saying though. It is a vacuum line going to the MAP sensor so it should be sucking only. Unless there was a backfire somehow, though I never heard/felt one. The engine was perfectly smooth then out of the blue it will start running ruff and smell like gas and the check engine light comes on. Hook it to the scanner and it shows 22...and yes, I disconnected the battery to reset the codes after replacing the MAP sensor the first 2 times, ran it a bit, then checked for codes again and it would show all clear for a week or so.
I do see what your are saying though. It is a vacuum line going to the MAP sensor so it should be sucking only. Unless there was a backfire somehow, though I never heard/felt one. The engine was perfectly smooth then out of the blue it will start running ruff and smell like gas and the check engine light comes on. Hook it to the scanner and it shows 22...and yes, I disconnected the battery to reset the codes after replacing the MAP sensor the first 2 times, ran it a bit, then checked for codes again and it would show all clear for a week or so.
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It showed up during KOEO test but the check engine light came on while driving. It was in the memory as well. After replacing the MAP sensor, I disconnected the battery to clear the codes. Rechecked and it was gone. Drove it for 10 miles or so and checked again. It was fine. Then a week later, after 70-80ish miles, check engine light came on. Did the KOEO test and the 22 was back. The code 44 only shows up during KOER test.
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Fleet Owner
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From: Easton,Ks
The KOEO test is an on the spot electrical test and you can not clear its codes as it checks for its codes each time the test is ran.
The codes that you can clear are the CM codes only and they happen while the trucks engine is running or driving on the road.
If you are saying you are getting the 22 with the CM codes then we can look that up.
Continuous Memory Service Code 22 indicates the Manifold Absolute Pressure (MAP) sensor was out of self-test range. The code was set during normal driving conditions. Correct range of measurement is typically from 1.4 to 1.6 volts.
Possible causes:
-- Damaged MAP sensor.
-- Damaged EEC-IV vehicle harness.
-- Damaged MAP/BP sensor vehicle harness connectors and/or terminals.
-- Unusually high/low barometric pressure.
The codes that you can clear are the CM codes only and they happen while the trucks engine is running or driving on the road.
If you are saying you are getting the 22 with the CM codes then we can look that up.
Continuous Memory Service Code 22 indicates the Manifold Absolute Pressure (MAP) sensor was out of self-test range. The code was set during normal driving conditions. Correct range of measurement is typically from 1.4 to 1.6 volts.
Possible causes:
-- Damaged MAP sensor.
-- Damaged EEC-IV vehicle harness.
-- Damaged MAP/BP sensor vehicle harness connectors and/or terminals.
-- Unusually high/low barometric pressure.
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