How to locate misfiring injector

slyhog022056

Full Access Member
Joined
Apr 28, 2016
Posts
108
Reaction score
4
Location
Grand Prairie, TX
97 F250 HD with 7.3 psd. I have a constant miss from one of my injectors. How can I trace it out electrically?
I swapped injectors with known good one and still have a miss. Do I need a oscilliscope to trace out the circuit? My high dollar scanner doesnt tell me anything.
Does anyone have a wiring diagram of the harness between the PCM and the injectors? I have looked and looked but to no avail.
Also having a problem with the ignition circuit. I can be driving along or sitting still and everything goes dead, like th key has been shut off. It fires right back up but at 80 MPH it is annoying as it sometimes does it 3 or 4 times in a mile stretch. Any clues? I have swithched the ignition switch and OHMed out the wires and terminals.
 

slyhog022056

Full Access Member
Joined
Apr 28, 2016
Posts
108
Reaction score
4
Location
Grand Prairie, TX
i need a diagram to know which wires are which. did a search and found 3 different descriptions as to which wire is which.
need to know if i am getting a pulse from pcm also.
i was getting 19 mpg then about 2 months ago it dropped to 14 mpg
 

79jasper

Chickenhawk
Joined
Oct 13, 2012
Posts
17,367
Reaction score
1,930
Location
Collinsville, Oklahoma
Google search the gbreman website. They have a article with the idm wiring.
If it isn't already, unplug the fuel heater.
Are you losing all dash lights? Or is the engine shutting off and the dash stays on?

Sent from my SM-G988U using Tapatalk
 

IDIoit

MachinistFabricator
Supporting Member
Joined
Aug 26, 2014
Posts
13,318
Reaction score
3,879
Location
commiefornia
this.

You must be registered for see images attach
 

greenskeeper

Full Access Member
Joined
Mar 16, 2013
Posts
995
Reaction score
202
Location
PA
97 F250 HD with 7.3 psd. I have a constant miss from one of my injectors. How can I trace it out electrically?
I swapped injectors with known good one and still have a miss. Do I need a oscilliscope to trace out the circuit? My high dollar scanner doesnt tell me anything.
Does anyone have a wiring diagram of the harness between the PCM and the injectors? I have looked and looked but to no avail.
Also having a problem with the ignition circuit. I can be driving along or sitting still and everything goes dead, like th key has been shut off. It fires right back up but at 80 MPH it is annoying as it sometimes does it 3 or 4 times in a mile stretch. Any clues? I have swithched the ignition switch and OHMed out the wires and terminals.

remove both valve covers

with the engine running look for equal amounts of oil coming from the spouts on each injector indicating they are all firing the same.

there should be no oil leaking from the top part of the injector

to disable an injector, unplug the two wire plug going to the injector....if the miss goes away you've found the problem cylinder
 
Top