I have a 92 Explorer with 146K. Recently the "Check Engine" light will come on after a few miles of driving and go out. It intermittantly comes on and goes out at any speed. I read the forum on there were similar posts but for a 95 and 96 explorer. The suggestion was to buy a scanner and post the codes. Is that the path I should take also? If yes, is there a particular kind to get?

Thanks, Tom

 

I have an Actron CP-9015 scanner. Very simple to use & comes with an xlnt instruction manual. Takes a couple seconds to hook it up & in a couple minutes it will flash your codes. I think I got it at Pep Boys.

 

You need to pull the codes. You have OBDI/ECCIV, and you can get a reader for about $35. The reader will be good for all Ford products thru 1995. Based on the description of your problem, I would suspect the TPS (throttle position sensor), but pulling the codes will help nail it down. If you are going to do your own work, you need a code reader.

Mike

 

FYI, my code reader consists of a $3 voltmeter and an old piece of wire. Check out these instructions www.dalidesign.com/hbook/eectest.html A $35 code reader might be a little easier to use, it's your call whether to buy one or not.

 

i may sound like a fool here but you could also try some injector cleaner...i had the check engine light come on and i only have 65k on my explorer i was like **** give me a break. ran a $3 bottle of super concentrated STP something and it went away but now 700 miles later its back on again lol. back to pep boys tomorrow

 

I tried the instructions provided my MRSHORTY. My 92 explorer had a 5 speed manual transmission.


The codes read out were 522 and 179.

522 - (O) Park/Neutral Position (PNP) or Clutch Pedal Position (CPP) circuit fault - PNP Transmission MLP sensor out of range in park - Transmissions

179 - (M) Fuel system was rich at part throttle Single, Right or Rear HO2S - Fuel control

From the description, I can't tell if there is anything I need to change or perform.

Thanks, Tom

 

Since it's rich on bank 1 only, I think I would give the injector cleaner a shot as mustangsvt suggested.
I'm sure that one of the real experts on this forum, such as mrshorty will have some thoughts on this also.

 

The 522 is probably just operator error -- running the test with the transmission in gear. Computer expects the transmission to be in neutral.
Did you run the KOER test? Any codes there? KOER codes can be more useful, because they indicate a fault that currently exists, rather than some fault that once existed, or occurs intermittently.
Assuming it is an intermittent fault, have you been able to discern any pattern to it?
Things to do at this point:
1) Rerun KOEO test with transmission in neutral until you get a pass code (111) for the KOEO hard faults.
2) Run KOER test. Be sure to run the test on a previously warmed up engine, and don't miss the Brake test and dynamic response (aka "goose") test, or you'll get false codes.
3) Inspect wiring to O2 sensor. Make sure there are no breaks, cuts, loose connections, etc.
4) Inspect PCM ground connection.
5) Check fuel pressure at fuel rail. Should be ~40 psig KOEO.

 

I did the KOEO and KOER tests using the multimeter approach. The only code I received was a 179 while doing the KOEO test. I will try some injector cleaner and also perform the other visual tests recommended by mrshorty.

Thanks for all the help and suggestions. Tom