Hello everybody. I am a new user to this forum and, unfortunately, not very knowledgable about auto repairs. Years ago, before the age of computers, I owned a Ford Club Wagon and did a lot of repairs on that (starter, exhaust system, rebuilt my own carb, etc...) but now I am daunted by all the elctronics and sensors and stuff.

Anyway, I now have a '93 Aerostar 4.0 L with about 210,000 miles on it. I've been good about taking it in for maintenance and service when it's been needed but now I'm starting to tackle some things myself. I recently replaced a healdlight switch and the accompanying wiring harness with little difficulty. After I finished, the van was running very roughly and would have almost no power when stepping on the accelerator. I had a friend who is a mechanic hook up his computer diagnostic thingy and he told me that my MAF sensor is bad. He didn't understand, though, why my engine performance would have been affected by replacing a headlight switch. I have since learned that disconnecting the negative battery cable can cause the powertrain control module to freak out until it "relearns its adaptive strategey"...whatever that means.

Anyway, I know what the MAF sensor is and where it is (I think) but it's an expensive part to replace and I'd heard that cleaning it could help. Does anyone have suggestions on what approach I should take and, for that matter, any resources on the actual steps involved? Thanks in advance for any insights you can provide.

Chris

 

Hello Chris and welcome to the Aerostar forum.
I too, agree that if the van were running fine before, a harness replacement should not affect things. If you were working under the hood there may be an inadvertently disconnected vacuum line. The MAF is on top of the air tunnel right after the air cleaner box, a small black affair with two retaining screws. Yours may have the "protected Torx" style with the small tamper resistant pin in the center. Some people try to knock out the pin but I would not encourage this as you run the risk of damaging the delicate MAF sensor underneath. Others cut a slot for a screwdriver or just use small pliers. Pull the sensor up and spray the inner hanging wires with an aerosolized electronics cleaner. If that does't solve the problem you might need to replace the sensor.

 

Hi Chris:

Welcome to our FTE forum

Just as Aerocolorado said, you'll need the security Torx bit set. Harborfreight has a very complete set of all imaginable security bits for less than $20. Remove the MAF, very carefully and see if the two anemometer wires are intact. If they are, all you need to do is to spray them clean with throttle body cleaner. It might help if you VERY CAREFULLY brush them with a kid's water-coloring small soft brush. But you have to be VERY CAREFUL!!!!!!!!

My suspicion is that when you replaced the headlight, you might have removed the air filter box for access, and in the process have knocked the MAF wiring around. You might even have disconnected it and forgot to pop it back in.

Good luck.

 

Hi -

Thanks for your quick replies.

I actually didn't replace a headlamp but rather, the headlight switch (and wiring connector harness) in the upper left of the dashboard. I had the negative battery cable disconnected for about 2 hours though. So, I think that's why it was running rough afterwards.

Anyway, my "Check Engine" light had been coming on intermittently even before I did the headlight switch. So, I had someone check that out with a computer diagnostic tool and I was told that the MAF sensor was bad.

My newest question is regarding what I should use to try cleaning it with. I have heard that you can use electronic contact cleaner (as you said, AeroColorado) but then I've heard you should use TB cleaner (as <i>you</i> said, Copper_90680). What's the difference? Will one leave an undesirable residue? Just curious which is the better bet. I really don't have the $220 that my local Ford dealer wants for a new sensor.

Thanks again. :-)

 

I prefer electronics cleaner because I know there is no residue. Not sure about TB cleaning agents but if copper_ recommends it, it must be good. People using K&N or similar oil impregnated air filters wind up with an oil residue on the MAF wire. Just the smallest amount causes problems. You can also buy MAF for less at most parts stores or pick up a used one from a junkyard.

 

first, disconnect neg. battery lead to protect ECU/PCM electronic brain

either TB or electric contact cleaner work for attempted cleaning of the MAF...I let it set in a shot glass full of TB cleaner for 10 minutes, let it air dry and then give it another spray...then air dry before installing

what type of air filter and when last serviced or changed?
keeping a clean free flowing air filter is important to a clean healty MAF

reconnect neg. batt. lead and drive for 10-20 miles for ECU to relearn adaptive memory....if still CEL then get a rebuilt MAF at your local discount auto parts store, far less expensive than FoMoCo and work as well....buy a national brand, Cardone, Neihoff, Beck/Arkley, Standard, some even carry Ford Motorcraft at a substancial discount

the new sensor comes in a cleaned refurbished housing because a new sensor has to be calibrated to each unique flow characteristic housing...the auto parts store will require your old MAF and housing for core charge rebate

 

Welcome!

You have been well covered on this, try it and let us know.