Dead Cylinder Fuel Injector Issue
09-24-2018, 06:38 PM
#1
Junior Member
Thread Starter
Join Date: Sep 2018
Posts: 7
Likes: 0
Received 0 Likes
on
0 Posts
Dead Cylinder Fuel Injector Issue
I have a 2008 f-150 with the 5.4 triton and cylinder 1 is dead. I checked spark plug, coil pack, and injector and all seem fine. I did a noid light test and it shows that the injector is not getting a pulse. What could cause this? Any input would be helpful. Thanks
09-24-2018, 06:44 PM
#2
Senior Member
Injectors don't get "pulses". The circuit gets grounded by the PCM and current flows. Check the injector plug for power.
09-24-2018, 11:52 PM
#3
Junior Member
Thread Starter
Join Date: Sep 2018
Posts: 7
Likes: 0
Received 0 Likes
on
0 Posts
By “pulse” I was meaning the noid light pulsing/flashing due to the pcm grounding. Poor wording on my part. The injector plug is getting power. When I plug the noid light into any other injector plug it flashes. It will not light up at all for injector 1. I used a test light to test the same thing and every other injector plug flashes the light. When using the test light the injector plug for cylinder 1 stays on constantly rather than flashing. I can’t figure out why it won’t light up at all with the noid light but lights up with the test light. Either way it won’t flash like the others. Any input appreciated. Thanks.
09-25-2018, 09:41 AM
#4
05 5.4l 3v s.crew lariat
If the wire going to the pcm goes to grd it will act that way
Your wire harness may be pinched on a metal piece . Or the output circuit of pcm is fried . I would swap injectors to see if it moves just in case . You could run a new wire to pcm plug from that injector . Unplug pcm and look to see if grd goes away with an ohm meter is another test . If it does then you need pcm fixed or replaced .If you get pcm replaced get that injector replaced to make sure it won't fry new one.
09-25-2018, 12:16 PM
#5
Senior Member
Actually, what you're saying is that it does light up. Just doesn't turn off. That's a sign of what redfish is suggesting. A short circuit or damaged PCM. Don't do too much testing since you know now because it means the injector is staying open and squirting fuel in to the cylinder.