Hello, new here with some issues.

[_Clayton_]

Hello everyone, I recently purchased a 93 4x4 limited with 91k from my in-laws. Thing seems to run pretty good but drinks gas, I only got 180 miles out of my first tank. I have replaced the plugs, air filter, fuel filter, and cleaned the maf. And on occasion stumbles, dies, misses upon hot restart, Usually clears up after a moment or two. Pressure regulator isn't leaking into the vacuum line but may be bleeding off internally. I have to pick up a fuel pressure gauge tomorrow too see what's going on. I have noticed a gurgling sound coming from the tank when it does this. Anyway I pulled the codes and got,

55 "No or low (under 7.5 V) Key Power to PCM pin 5"

56 "Vane Air Flow (VAF) or Mass Air Flow (MAF) sensor high"

65 " Check intermittent HO2S (signal or ground)".

The check engine light doesn't come on.

I suppose the first thing I need to do is check pin 5 on the pcm for voltage. How do I determine pin 5?

Thanks

 

[_Clayton_]

Ok I went out this morning and pulled the ecm, Found pin 5 and found no voltage coming to that wire. So I ran a jumper wire to it, ran the engine for a few minuted and rechecked the codes and this time I got code 22 and 65. The engine is way more responsive with the jumper wire hooked up. Does anyone know what pin 5 goes to?

 

[TedJ]

I think you have some other problem, either a defective ECM or a bad ground/power circuit to it. Pin 5 is shown as not connected in the pinout chart for all versions (limited, cali emissions, I checked them all) in '93 so it's not supposed to be connected.

I don't even see code 55 listed in the ford manual for '93, which makes sense because there is nothing connected to pin 5.

Code 22 is for MAP or BARO (diesel) applications, which again do not apply to this vehicle.

Check that you are reading the codes correctly. If you are, check all the vehicle grounds and positive cables, if they are ok you might want to try a replacement PCM.... the codes you are getting do not make any sense.

 

[_Clayton_]

Thanks, Pin 5 does have a wire coming from it. And I only got code 22 once after that it went back to 55 56 and 65. Never could get it to give code 22 again. I dunno, Seems to run ok otherwise but is very thirsty.

 

[_Clayton_]

Ok after the engine is ran for a while I get code 53 95 and 65, If I reset the ecm it goes back to giving 55 56 65. Who the hell knows, I suppose I need to go over all the grounds tomorrow then go from there.

 

[mawrazen]

I had mileage issues on my 1994 until I replaced to 02 sensors and the tranny modulator valve. The modulator valve passes atf into the throttle body when if fails.

How are oil and ATF fluid levels?

Also when did u last reset the computer?

 

[TedJ]

I'd say first thing first is figuring out what is going on with the codes. Trying anything else is a waste of time if the computer is unhappy. Have you ever read codes from the ford ECMs before? I assume you are using the CEL light flashes to get the codes? Basically I just want to male sure that you really are getting the codes that you say you are because they seem to make no sense.

 

[_Clayton_]

I'd say first thing first is figuring out what is going on with the codes. Trying anything else is a waste of time if the computer is unhappy. Have you ever read codes from the ford ECMs before? I assume you are using the CEL light flashes to get the codes? Basically I just want to male sure that you really are getting the codes that you say you are because they seem to make no sense.

Yeah I've been counting flashing CEL's since I was a teenager. And I am using the CEL method to get them. Your right they make no sense at all, seem to be random at times. I went over all the grounds today and it didn't change anything.I'm supposed to go in the morning to pick up another ECM, It's from a 93 as well but I hope the numbers match, If not I guess I'll try it anyway and see what happens. Gonna pick up some other sensors for spares while I'm there. I'll figure out the hot restarting issue after I sort through this.