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Discussion Starter · #1 · (Edited)
I need help REALLY BAD! I know this forum is for Ford 6.0 however I have a 2006 International VT365 (very similar) with a turbo solenoid that won't stop "buzzing" with the key on and engine off. It is a really loud buzzing and is not the injectors, I have removed the wires from the solenoid to verify this. It buzzes 100% of the time however the tone and volume change depending on how hot the engine is, if the glow plugs are on, or if my brake compressor is on. I have replaced the EBP, EGR, the entire turbo, the actual solenoid, glow plug relay and checked/rechecked just about every wire and connection.
I don't have the ability to pull any codes (not yet) and I am a rookie at best when it comes to low voltage auto wiring. It is my guess that I have a short somewhere or my PCM is malfunctioning. There seems to be a correlation between the glow plugs and the volume and pitch of the buzzing, but that could be because the glow plugs are sucking voltage from the batteries and when they shut off more volts get sent to the PCM (this is a total guess). I did test the wires going to the solenoid and there is about 10.5 volts when the glow plugs go off, and about 9.6 when they are on.
Please help!!! I never intended to become a diesel mechanic……..
I should also add that the vehicle seems to run fine with no boost issues or power loss, there is however a lot of black smoke when I lay down the pedal but goes away immediately.
 

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I'm not sure what would cause it to buzz. I will say that the best way to see if its working properly is to view the vane sweep with something that will read it like an SGII. When you start it up do you get a change in pitch of the exhaust note while its warming up at idle?
 

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Discussion Starter · #3 ·
Thanks for the reply.
I am going to get a Scan Gauge D tomorrow to check the vane sweep, it looks like I can get DTC's from it also….
I don't notice any change of pitch in the exhaust when warming up. It's odd because I feel like the engine and turbo are running great (other than the black smoke as mentioned).
I have take the solenoid out, re-attached the wires and turned the key on and it is completely silent. I have also (not sure if this was a good idea) attached a direct 12 volt wire to the side of the solenoid that had the 10 volts while it was attached to the turbo and I could here the solenoid cycle on/off without the loud buzzing noise.
Is there supposed to be constant voltage going to one wire while the other sends a signal from the PCM?
Thanks for helping!
 

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No, it doesn't work that way. In fact voltage to the solenoid will vary in operation. This solenoid isn't a simple on/off device. The amount of voltage applied will directly correlate to how far the plunger moves, which in turn affects the position of the vanes.

I would also advise checking the wiring to it, as it tends to get screwed up from heat. You need to peel back the split loom and check as far down as possible.

That black smoke isn't normal, and I would take as a sign that the turbo vanes are in the wrong position at that point for the fueling. A stock motor should never do that from my experience.
 

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Basically the solenoid position is determined based on input from the EBPS, but some models don't even use that; they use an inferred EBPS value strategy. Those were early trucks though, and if the PCMs ever been reflashed at the dealer the strategy has been updated. I do believe that in those strategies they are reading off the MAF and MAP sensors to infer engine load and air mass, which in turn determines timing and fueling. Basically there are just tables in the PCM for various data points and it moves the solenoid accordingly.
 

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Discussion Starter · #7 ·
Thanks for your help!!! I totally appreciate it.
It has been updated recently according to the dealer so the MAF & MAP could be the next 2 I look at. However after hours and hours of looking through these threads and online I can not locate either of those 2 sensors. Do you know where they are located on the International VT365?
If it matters, this all started after coming back from Colorado to California so there was a big drop in elevation. I have read that the MAP or MAF sense the altitude or air pressure (not sure). Thought there might be a relation to this at one point.
I removed all the split loom and checked the wires thoroughly today and found nothing abnormal.
 

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The BARO sensor is for atmospheric pressure. It's inside the cab. You can do a quick check of it with the Scan Gauge. It should be reading 14.7psia.

Do a Google search for the "6.0L Bible". It'll have all the component locations and descriptions you need.
 

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Nope.

IMO, you have an electrical gremlin. Kind of sounds like a short to power or a partial open. I'd start checking voltages, continuity, etc....
 

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Just re-read your original post. You have low voltage to the VGT. You need at least 11 volts for it to work properly. In reality, it should be running about the same as battery voltage.

Could be as simple as a battery problem. Get them load tested.

If they check out good, look here for the Ford VGT pinpoint test: https://www.motorcraftservice.com/pubs/content/~WV3D/~MUS~LEN/15/V3D5065.HTM
 

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Batteries can show good voltage static, but fail under load. I've seen in many times. I had one once that showed 12.4 volts, but when the engine was cranked it dropped to 8 volts and would barely turn the engine over. That's why a load test is the true test.
 

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Get your alternator tested while you're at it. A bad alternator can take out your batteries and bad batteries can take out your alternator. When chasing electrical gremlins, you need to start out with as many knowns as possible. Testing both will insure that you have a good voltage supply.
 

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Discussion Starter · #15 ·
Batteries were bad, got 2 new ones under the battery warranty. Put them in, no luck, the turbo solenoid still buzzing….Hooked up the scan gauge 'D' and 2 codes popped up, 639 14, and then for some reason (don't think I did it) the 639 got erased and a 625 14 is showing.
 

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Those aren't codes us Ford guys are used to seeing. I did a quick search and the 639 code seems like an OBD code that probably cleared itself after a few scans. The 625 code is beyond me. Sounds like something ECM related.

Do you have access to any of the IH data for the codes? Did you run the pin point test I posted?
 

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Discussion Starter · #17 ·
The only thing I found on a search for the 625 was for "a switch and door pod", which I have no idea what that means.
I did do the pin point test and got as far as AK2. It says "is voltage greater than 11V", which mine is at 10.5 so the solution was "repair open in circuit". This may seem ignorant, but I am not sure what that means….I removed all the split loom and gobs of mushy electrical tape and traced both wires from the solenoid and they appeared fine. One wire went to the ECM (that is the one with 10.5V) and the other wire went to plastic part on top of the ECM with about 10 wires going into it. I checked the voltage on the wire that reads 10.5V with the key on and the solenoid connected (while it was buzzing) and it was 4.9V. In other words….when I remove the wire from the solenoid it has 10.5V and when it is connected it has 4.9V.
Is my ECM crap? Maybe a bad ground?
 

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Open is electrical speak for a bad ground. I would start there.
 

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It could be a break anywhere in the circuit, supply or ground side. Think of it as an air gap or a partial air gap. If you check the circuit for continuity (ohms), it'll show infinite resistance.

Based on your voltage readings, there's most likely a gremlin at play. Unfortunately, it's tough to help someone diagnose an eletrical issue over the internet. You need to check every wire for continuity and a short to ground. You might also consider cutting the wires on either end of the circuit and splicing in some wire to bypass all the stuff in the harness (last resort....I hate to cut into a harness and start butt splicing).

You also can't rule out a bad ECM. Do you have a known good one you could swap in?
 
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