Hello, for everyone, i'm writing for you from the tiny country of Lithuania, in order to discuss some technical nuances of my Ford F700. So the thing is that my truck is working inconstantly, it feels like computer limits (practically stops) the engine everytime i'm above 70km/h. I was pretty sure that computer is working in some kind of failure mode, but i have done both KOEO and KOER test and no serious faults were found. The only thing that I can not understand is the number of the cylinders shown at the beggining of the KOER test. I have done this test couple of times, first time computer shown 6 cylinders, after couple of hours I have decided to re-test my ford, and than it became 8 cylinder truck (as it should be), just to make sure I have re-tested it again, and guess what its 6 cylinders again. Could you please explain me how the computer counts the number of cylinders? and what may be the problem of intermittent operation of the engine? (At first, I thought its spout connector, because i had found it opened, but I have already made a circuit here, and yes it seems like computer at least tries to control ignition, but the operation of the engine is still dar from perfect. I think that ignition control module may be the problem, but i have no ideas ho to check it.) P.S. I have already changed distributor cap, and its rotor. Please respond to my post, because every comment may be valuable, and you are pretty much my last hope

 

70 km/hr = 43.5 mph... just to clarify for us metric challenged. Will it rev above the rpm it is cutting out at in a lower gear? When it cuts out, is it missfiring or does it feel like it is running out of fuel? Have you checked fuel pressure?

 

It seems like truck is out of fuel, anyway, I think I have found the problem, it's MAP, and oxygen sensor. I have already found MAP sensor for replacement, but having some problems with oxygen sensor. Could you please tell me what oxygen sensor fits to me? I'm thinking about universal oxygen sensor, but as far as I found out, they differ in a number of ways.

P.S. Just to remind you, my truck is: Ford F700 1995, 7.0L, V8 (VIN: 1FDXF70J2TVA13642)

Thanks in advance!

 

What do you mean number of cylinders shown in the KOER/KOEO tests?

 

Well, I have done Key On Engine Running diagnostic test with Ford code reader device, and at the beggining of this test device shows how many cylinders ir sees, so for some reason it keeps showing 6 cylinders instead of 8. Another problem is oxygen sensor, I just can't find any fitments for my F700...

 

I would think a 4-wire Heated Oxygen Sensor for a Ford truck in the 1992-1997 range will work for your application. These heavy duty trucks are hard to find parts for using consumer grade websites and catalogs.