#6 injector stops pulsing

[Mizark347]

When I first start up my car everything runs great until the #6 injector stops pulsing after 10-20 seconds of run time and my air-fuel starts to bounce around. I checked this with the injector connected and disconnected with a test light. It always gets a constant 12 volts to the power wire and will pulse the ground side of the injector connector at start up and then stops. All the other injectors are getting the correct pulse all the time except #6. I can't figure out why this would be. Anyone have any input or experience with this. Thanks, Mark.

 

[MalcolmV8]

What equipment are you using to measure these pulses as I'm sure they happen at hundreds of times per second. Break in the wire harness between injector and ECU?

 

[Mizark347]

Just a test light that I can watch flicker at a high rate. It works fine during the first few seconds of startup and stops. So break in wire doesn't make sense to me.

 

[CtSvt]

try switching the injector to a different location and see if the problem continues on a different cylinder , that will tell you if its an injector issue vs a wiring issue

 

[Mizark347]

That's the next thing I was gonna try

 

[Mizark347]

If the ecu detects a misfire does the ecu then command the injector to stop pulsing?

 

[MalcolmV8]

If the ecu detects a misfire does the ecu then command the injector to stop pulsing?

I've never heard of that. I'd try swapping injectors as mentioned above and see if the problem follows the injector or stays with the cylinder.

 

[Shadow Grey 03]

What injectors? Aftermarket with adapters?

 

[Mizark347]

had some 21# injectors lying around and put em in place of my 80# injectors to trouble shoot this issue. So im pretty sure it's not the injector but maybe a fouled plug and the ECU is shutting of the injector on the cylinder that isn't firing. I'll know more tomorrow when I can do more troubleshooting.

 

[Mizark347]

I changed the #6 spark plug and it fixed the injector issue. It appears that Ford has the ecu to command the injector to stop pulsing if a spark plug isn't firing. I guess it was just a fouled spark plug. I put my 80 lb'ers in and it's running good!

 

[MalcolmV8]

Glad to hear it.