Diagnosing MAF sensor codes?

[samtheham]

My 92' exlorer has a rather bad hiccup. I just bought this car recently even with lots of miles it is in really good mechanical and asthetic shape. The poblem occured the night after I changed the air filter. The dirty little "CHECK ENGINE!" light decided to announce problems on the horizon and goes on and off, when on and the computer is in default mode it runs as to be expected, poorly. When it is off, the car hesitates, doesnt like to start from cold and ever minute or so has a lean surge with the rpm's and power dropping just for half a second. When I got the engine code for the problem there were three codes, 998-Hard fault present, 157- MAF sensor below min. voltage, 158 MAF above max. voltage. Now, during the last oil change the engine got overfilled by about half a quart, nothing I thought to worry about, the oil pressure stayed well within limets. But apparently the PCV valve has let more then just harmless oil fumes enter the air intake, I found minute traces of oil in the air passage between the MAF and the Throttle body. I cleased the whole passage way, free from oil and cleaned the sensor and aluminum housing with injector safe "carb" cleaner. There was a small amount of just visible black "dust" on the sensor that cleaned right off with spray. there was no visible builup into the throttle body or maniford. I belive that while changing my air filter I might have somehow yanked on the MAF harness and may be experinecing a short or a MAF sensor failure. Any suggestions as to how to check for a short or bad sensor would be very much appreciated.

 

[Alec]

First of all, welcome to the site! Blah blah blah best Explorer site on the net blah blah blah

Did these codes come up before or after you did the cleaning? If before, then try resetting the computer. If you don't know how to do this, ask

Good luck!

 

[samtheham]

Thanx for the welcome, I got those codes before and after the cleaning, I erased the problem codes both times (boefore and after) with no avail. The book I have points to either the MAF or MAP sensor as the culprit and the codes point to the MAF sensor. I think that more or less narrows it down to just the MAF sensor or the wires connecting it. The funny thing is that it only crapps out during hotter running, it worked fine all the way home tonigh when it was a little cooler. Tomarrow I am going to go ask a mechanic that I used to work for if he has any ideas before I blow $120 dollers just to try the shoot-and-miss approach.

 

[samtheham]

Turned out to be a faulty MAF sensor, new sensor seems to have solved my problem