#7 injector issues plz help diagnose

ghohouston · Jul 8, 2013

neverkickn said:
I never said or implied that I wanted you to be wrong just for the sake of proving someone wrong. This is a tech thread, check your feelings at the door. I just don't see a bad solenoid causing a code and ohming fine at the same time. It works or it doesn't. He said the circuit ohmed good so why would you rule out an injector malfunction.

Im gonna agree with you on this one. I dont see how 1 bad solenoid would shut down a whole bank. They would have to be wired in series for this to happen, right?

ActionRick · Jul 8, 2013

ghohouston said:
Im gonna agree with you on this one. I dont see how 1 bad solenoid would shut down a whole bank. They would have to be wired in series for this to happen, right?

The IDM is in charge ...

ActionRick · Jul 8, 2013

neverkickn said:
I never said or implied that I wanted you to be wrong just for the sake of proving someone wrong. This is a tech thread, check your feelings at the door. I just don't see a bad solenoid causing a code and ohming fine at the same time. It works or it doesn't. He said the circuit ohmed good so why would you rule out an injector malfunction.

He said the CEL comes & goes depending on what is plugged in or not

did a long trip this Canada Day weekend.
went from Vancouver BC to Grande Praire AB to Fort St John BC and home.
truck started acting up after Grande Praire. first symptom was laboured starting.
after loading a car on the trailer in FSJ I fueled and grabbed breakfast and coffee at Tim Hortons and went to pull on to the highway.
CEL and motor starts chugging badly.

so on the side of the road I start trying to troubleshoot.
Torque app says "no codes stored"
oil level is good and clean (changed 2 days before trip with T6 synthetic and a donaldson elf7405 huge filter)
fuel in the bowl, filter fresh as well
if I unplug the left rear valve cover connector it runs better and CEL is off

so I pull the valve cover to inspect the UVCH. it looks perfect and DVOM says its good but I failed to check for continuity between the injector pins
injectors 3.5ohms
nothing looked 'bad' under the covers so I buttoned them back up.

I pulled the pins from the harness connector and tried disabling 5 and 7 seperately.
5 disabled 7 connected motor ran rough like on six cylinders, 5 connected 7 disabled it smoothed out on seven cylinders, bothe 5 and 7 connected CEL and rough running

at that point 1300km from home and having to be at work I pulled 7 from connector and hit the highway on 7 cylinders

missed work on Tuesday and worked today.

to me it feels like 7 is trying to fire out of time.
having 7 connected the starter works very hard to spin the motor.
I guess I have to try a few more continuity tests at the valvecover connector but everything there 'looks ok'
so I guess the next place to look at wiring is back at the engine harness plug on the driver side?
do injectors die like that? is it electrical?

any help is appreciated

I guess oil pressure & or injector comes & goes

m j · Jul 8, 2013

the CEL part baffled me too. it only came on when both 5 & 7 were plugged in, with either one not 'in' there was no CEL. could it have been a cylinder contribution thing???
TorqueApp not finding a stored code bugs me a bunch

what i learned from this is that injector o rings are a wearing item, and I now understand something I read on the forums awhile ago.
someone asked "what is the black stuff on the FPR screen that i have to clean off?"
a wise man answered "Your injector O-rings"

anyway I put off the injector order and ordered my s467fmw from BD, and comp 910 valve springs from Mopac.
I am going back to the original build schedule where injectors come after everything else is in place.
my srp1.1 arrived from Irate today along with my DI fuel fittings (thank you Jacob and David)

ghohouston · Jul 8, 2013

ActionRick said:
The IDM is in charge ...

look im not claiming to be a super mechanic here, but i have worked on hundreds upon hundreds of powerstrokes, and not once have i seen a bad injector solenoid take out a whole bank of injectors

ActionRick · Jul 8, 2013

ghohouston said:
look im not claiming to be a super mechanic here, but i have worked on hundreds upon hundreds of powerstrokes, and not once have i seen a bad injector solenoid take out a whole bank of injectors

OK......

neverkickn · Jul 8, 2013

ActionRick said:
He said the CEL comes & goes depending on what is plugged in or not.

Perhaps it is an observational error. Things can get confusing quick when you are trying to troubleshoot a problem like this.

I can't say for sure on an obs but I can tell you when you unplug an injector on a SD you get a cel. There will be a code telling you that you have idm codes stored, and you have to do a buzz test to retrieve them. Plug the injector back in and the code is still there but the light goes off. If you had a bad solenoid you should have a constant cel.

According to those in the know you can have a bad injector that causes the idm to believe there is a circuit fault due to the effect that a worn injector has on the EM field of the coilpack.

I guess oil pressure & or injector comes & goes

With variations in temp yes it will. The fact that he unplugged an injector and the truck ran better is not an indication of the health of that particular hole/injector. It only means that unplugging that injector helped balance the rotation.

OP I bet you have either a compression or injector issue. You really should do a compression check before you dump money into this motor, and you may as well do your injectors first and adjust your tuning to match your setup as you will be unhappy with that charger and worn injectors.