I've done all I can do without playing musical parts until it is fixed.

2004 6.0 330k miles, EGR deleted, heads studded, new engine wiring harness a year ago, stc fittings, blah blah..

The truck is idling rough and it does not go away, started all of a sudden last week. The only code I get is P0264 which is low voltage to cylinder 2 circuit I believe.

It sounds like a stiction/injector missing when it is running, but it still runs and drives OK enough to get around and drive. Someone who doesn't know these trucks probable wouldn't even notice it.

I just changed the oil with Rotella Synthetic 5w40 and 2 bottles of REVX hoping it was just stiction and would go away. After 1.5 tanks of fuel it is the same.

The FICM is at 48+ volts under load and idle etc. The wiring harness connectors are firm. I disconnected the injector on cylinder 2 and noticed some rub on the harness but no visible wire damage. There is what looks like a slightly deformed spot on the connector (heat damage maybe but very small).

Here is where I am stuck... I'm not sure how to proceed other than replacing the harness, then injector, then FICM.... Is there a cheaper/more efficient way to check theses components?

I've heard of moving the injector harness to a different injector to see if the code changes to that cylinder.. would that not hurt anything to run on the wrong one like that though??

Any guidance is much appreciated..

 

Are you checking FICM cold ? That's when you will see Voltage drop, and have you load tested battery"s separated ? Then proceed to injectors test.

 

You can disconnect the harness at the suspect injector and measure the resistance of each coil to determine if they are electrically open. Measure between pins 1 and 2 for the open coil and pins 3 and 4 for the close coil. A typical reading is about 0.8 to 1.0 ohms which is in the middle of the specs. You can find pin numbers on the face of the connector molded into the plastic and they are very small. A light and a magnifying glass might help you read them. If either coil does not meet specification the injector is bad and needs to be replaced. If the coils test good then you need to test the harness circuits. If those test good the FICM is suspect.

 

Mark is spot on.
Ill add to test for shorts from open coil to closed coil.

 

Ok, thanks for the help guys.

I finally had time to test the injector today and both sides fluctuated between 0.6-0.7 ohms..

Is that enough to say the injector is definitely bad?

I thought about downloading the android app that can run the injector buzz test but wasn't sure if it was worth the time to put everything back together if 0.6-0.7 is sufficient to know the injector is toast.

Thanks!

 

Is that with the leads zeroed out?
.3 OHMS is whats expected. What do the other injectors read?

 

Yes, leads zeroed out. I thought 0.8-1.0 was ideal?

I will check the others, probably should have thought of that..

 

Ok, so the #4 injector had the same reading, around 0.7 ohm.. I'm assuming that means they are okay?

Is there a procedure for checking the injector harness or individual connectors?

Is there any other test I should do on the FICM, internal inspection, something like that?

 

Just in case anyone searches for a similar problem, this ended up being an FICM logic board issue.

Even though my FICM was replaced in 2011 with a reman, and was showing good 48V+ voltage at all times, the logic board was damaged and causing P0264 and P0265 codes, and rough idle, shaking etc.

If anyone is in the Oklahoma area I highly recommend:

AR Speedometer & Gauge
3014 N 74th E Ave
Tulsa OK 74115

They have rebuilt and upgraded 53V FICMs available for $239.00 or they will repair yours for the same price.

 

I've never heard of them. So they work on instrument clusters as well?

 

Glad you Götter back up and running .

 

Yes, instrument clusters are there main thing, but they rebuild a lot of automotive electronics.

One of them drives a 6.0 that they use to test all the FICMs they rebuild.