code problems need help.

[garagedog369]

just got a "94" eplorer. i've replaced the throttle postion sensor, and the tube from the e. g.r valve to the exhaust manifold. but don't know where to start now. i'm getting 4 new codes. #172 HO2 sensor fault lean. #176 HO2 sensor fault always lean. #185 mass flow sensor below normal. #186 fault in injector pulse width circiut/high. i don't kn0ow what to replace or what to clean, any help

 

[arco777]

A bad MAF will throw all kinds of crazy codes. Without good MAF input, the PCM won't know how much fuel to give, and you'll get codes like the ones you have. I'd start with the MAF, although it is an expensive part to just throw at the car. Check the sensor element wires on the MAF and clean them if they're cruddy. If that doesn't fix your issue...

If you do a search, there are ways to test the MAF with a multimeter. All Ford MAF sensors of this vintage are made about the same, just calibrated differently, so a testing how-to for Mustangs will work just as well.

You can always try swapping in a junkyard MAF, though that is a coin toss whether or not the car is in the yard because of a bad MAF. You'd want to install one from a first gen Explorer.

You didn't mention whether your Explorer runs badly or not. If it runs badly due to a failed MAF, often you can try unplugging the MAF and see if it clears up. If that makes your truck run better, the MAF is usually bad.

 

[garagedog369]

thanks. and the explorer runs 75 miles round trip dailly. it has power issues and a check engine light going off and on,mostly on.

 

[arco777]

I don't usually recommend throwing parts at a problem but in this case it sounds a lot like your MAF is failing.

 

[Bwana Bob]

A failed fuel pressure regulator will also generate a lean code. Fuel pressure gauges are relatively inexpensive. The fuel pressure should read 30-35 psi with the vacuum line connected and 35-40 psi with the line disconnected.

Also, I have experienced severe loss of power when the fuel filter failed and dumped dirt which clogged the injectors. It took a new filter and several treatments of fuel injector cleaner plus Marvel Mystery Oil to clear it up. (Do not buy Fram fuel filters. Spend an extra couple of bucks and get Motorcraft).

If the MAF does not read open with an ohmmeter, then it's probably OK, or good enough.

Bob

 

[garagedog369]

thank guys. i tried unpluging my maf senor and it hardly ran. it usaully idles fine. but it barily ran. my ohm meter made a ran to okalahoma by mistake.and i work 12 hours a day so this problem will try to be sovled this weekend. will keep you informed. i may need your help.