It all depends on which position the actuator was in when it failed. If it is positioned somewhere in the middle, you're good to go. If it's open too far, it will be extremely laggy and have high EGT's until you get RPM up. Closed up tight like the EB is on, don't run it!

The company I worked for has a fleet of Kenworth trucks with ISX engines. We've had our share of VGT issues over the years. In fact, I had an actuator fail and was doing random weird stuff. I ended up having to unplug it to get back to the shop. Luckily, it was positioned perfectly for the load I was hauling.

One thing to keep in mind is that the turbo plays a critical role in the regen process, so don't delay fixing the problem since it may stop the truck from even attempting one. If you're deleted, you will be fine with it unplugged and probably won't even get a CEL.

I would start by checking for a short since it keeps blowing fuses. I found a diagram for the VGT wiring, so you should at least know which wires do what.

 

@Mikey-KE7LBB - Thanks for the reply, I appreciate it. It is definitely not closed like the EB is on. I can't say for sure if it's partial or not. I don't need it for about 10 days but if I do drive it before it's fixed I will watch the EGTs.

Thanks for the wiring diagram. I'll check for short as you suggested. I'm not sure how common this problem is but truck only has 108,000 miles on it, not a lot for a 13 year old truck.

 

I just found this old thread describing same problem two other users had. One user replaced his turbo with used unit from another forum user and the other replaced just his VGT actuator. Just thought I'd link it in here for convenience if someone else has the same problem.

Turbo actuator blowing fuse 37

I'm still at the troubleshooting stage and will update my progress when able.

 

Update. I conducted the following tests:

I confirmed voltage at actuator harness (engine side) coming from relay (pink/orange wire)was same as battery voltage. It was 12.53 volts.

With ohm meter I checked grounds on other components in same circuit. I checked between:
— MAF sensor and air intake sensor (brown/orange wire), got 000.0 ohms
—clutch fan and MAF sensor (brown/orange wires), got 000.2 ohms
—clutch fan and air intake temp sensor (brown/orange wire), got 000.1 ohms
—back pressure sensor and MAF sensor (brown/orange wires), got 000.2 ohms
—back pressure sensor and air intake sensor ( brown/orange) wire, got 000.2 ohms
I also checked ohms between the actuator and EGR cooler bypass wire ground wire (dark blue/tan) and got 0.000 ohms.

So, unless I’m missing something I think I’ve ruled out an electrical short in the wiring.

Next step will be to drain the coolant, pull the turbo actuator off and see if the gear lever in the actuator is ceased up/partially ceased. From what I’ve read it should move freely with your hand once off.

 

Make sure you mark the position of the gear and don't move the actuator gear or turn the key on while apart.
The actuator is calibrated to the lever and once assembled any change in either the gear or lever position will cause you problems.

If the actuator is bad then the self calibrating City Diesel replacement actuator is a good choice.

 

Make sure you mark the position of the gear and don't move the actuator gear or turn the key on while apart.
The actuator is calibrated to the lever and once assembled any change in either the gear or lever position will cause you problems.

If the actuator is bad then the self calibrating City Diesel replacement actuator is a good choice.

Roger that! It'll be a while before I have time to pull it off but I'll post my findings then.

 

Well, I finally got around to this job. After pulling inner fender off to get at the turbo actuator, I pulled it off and marked the position of the gear on the actuator itself and then marked the position of the lever on the turbo. The first test was to grab the lever on the turbo that moves the vanes to see if it would move and it would not budge, in either direction. My assumption is that there is some sort blockage or build-up in the turbo that is preventing the vanes from moving and I unfortunately need to buy a new turbo.

Next, I plugged the actuator back into the harness while it was detached from the turbo, reconnected the battery, then cycled the ignition key on and off.......nothing, no noise from the actuator and actuator gear did not move, at all. My next assumption, the actuator was fried from trying to move the stuck vane lever on the turbo and I need to buy a new actuator along with a new turbo. So, I re-installed the actuator and got on with the task of pulling the turbo out of the truck.

Pulling the turbo.....I fought with every damn nut and bolt to disconnect the oil and coolant feeds to the turbo and to get the turbo off of the manifold. I didn't break anything, thankfully. The heat gun and CRC knock'er loose penetrant were my pals when it came time to loosen the turbo to manifold nuts! I also needed to drop the exhaust off of its hangers and disconnect the downpipe on both ends to allow it to drop down enough to to get turbo studs down below the manifold's mounting surface. Oh, I needed to get the BFH out to pound on the downpipe to get it separated from the turbo. When the turbo was loose and ready to pull out I could not get it out of either the upper or lower openings so I ended up pulling the battery and battery box out of the truck too in order to make enough space to pull turbo out. A few sentences capturing hours of 😡 work.

With the turbo now on the bench, I pulled actuator back off of the turbo to show my son the stuck lever and it was now moving back and forth. Did I somehow unfreeze the stuck vanes while beating on the downpipe with the hammer or while struggling with it to pull it out of the truck?

Now I'm scratching my head. Do I just replace the actuator and put the turbo back on? Do I buy a new turbo and actuator? Do I buy just an actuator and dis-assemble my turbo and try to determine the issue and maybe rebuild it?

Hmmmm......

 

Most of the time the lever will always move no matter what on the turbo unless just severely stuck. Even if it was 100% stuck and now it's moving, think of it as it was caked with hard mud. Just cause you broke it free doesn't mean it's 100% ready to rock and roll again. You are or will more than likely be buliding the vains over mud underneath the leve. By mud im meaning soot. If you already have it off, might as well either rebuild the whole thing or clean it.

Most definitely replace the actuator as it sounds like it's gone. However, if the turbo is shot and you put the new actuator on, you might fry your new actuator in the upcoming months. Keep that in mind as well.

As you can see it's not a fun job removing the turbo but as you do it a few times it gets easier.

Feel free to shoot me a message if you have any questions. Happy to help!

Clayton

 

I've decided to replace the turbo and actuator (City Diesel version).

 

Remanufactured Turbo with City Diesel Actuator arrived and installed. Problem fixed - fuse not blowing, exhaust brake is working again, and CEL off/codes cleared! I poured some oil into turbo oil inlet before reconnect oil inlet hose and did an oil change and coolant flush while I was at it so there's both fresh coolant and oil going to the turbo.

Hopefully this thread is helpful to someone that may experience the same issue.