i have a f53 motorhome and 4 out of the 8 injectors pulse. the front 2 and the back 2 dont pulse. the middle 2 on both sides work perfect. why would they not pulse and only give out positive on the two wires to the injector on the one that dont work. the ones that work they pulse.

 

The computer is not grounding the bank of injectors that do not work.
You have a either bad wiring from the computer to the injectors, the engine disconnect plug is bad, the Computer plug is bad or the the computer is bad.

For my own information what is the part number that is on your computer.
It is located just behind the foot brake and column inside the home.
The number will be something like F4TZ-12A650-AMA
The program code would be something like TOE0.
Also have you been able to find the Calibration Code for your unit?

 

the codes are something like this my girlfriend readed them off to me over the phone but i think so is missing some. eec-ivcsi f4tf-12a65 64ese48n44. were is the engine disconnect plug? when this problem started i was leaving a camp ground i turn it off and on a couple of times but the missing didnt go away till i drove about a half mile then ran great to the gas station. i turn off the engine got gas it started again and went away in about a half a mile. it got me home but now the problem wont go away. it came back every time i turn off the engine. how can i check out the computer? thanks for all the help i have been looking at this engine for a week.

 

Sounds like the PCM is failing.

 

i think it is the computer. the number is f4tf-12a650-ama. the problem finding one.

 

ok i pull out the computer and im looking for bad wires before i order a computer when i find one. the colors on the injectors that aren't working are tan and red. what color or port on the plug to the computer is for what injector? i tested a plug / wire from one injector plug on the tan side and i get 9 hot ports on the plug to the computer. im looking to see if i got raw wires before i cut the loom apart. i saw one raw wire in the loom on the left side of the engine disconect plug i was wondering if it was a fuseable link if its not i will cut it open and fix it. do all four injector open at the same time to be wired togther or do they open at different times?

thanks

 

If my Chiltons manual is right the tan wire goes to pin 58 only, but to verify this you have to disconnect the 4 injectors because otherwise they are connected to the signal return lines through the injector coils. This EFI system fires the injectors in batches of 4 so this does look like a wiring or EEC problem in your case.

 

i'm ordering the computer today so we will see if that will fix it thank you everyone. i will let you know.

 

Good luck!!

 

I have this exact same issue on my f 450 dump truck I have pulse on 1,4,5,8. And obviously none on 2,3,6,7. I replaced the computer and it still the same? Help??? I can't figure it out

 

Bad wire or connector between the computer and the injectors or a bad connector with a pin pushed out.
What year truck and engine?