Turbo issue, ideas?

OBS F350 · Jan 19, 2013

I need a little assistance diagnosing a turbo issue. My truck is an 05, automatic, all stock except 5 inch exhaust (4 inch downpipe). Has had an issue that I never really thought to look into until tonight. Before tonight at random times cruising at highway speeds with just holding the pedal steady or cruise on sometimes it would randomly gain and loose 3-7 pounds of boost pretty rapidly. And cause a mild bucking, you would feel it power up a little bit then slow down, so on and so forth. Also when idleing/high idle it will randomly kick off the hairdryer noise to just motor noise out the exhaust no turbo noise. Then back to hair dryer, sometimes will do it multiple times during a 5-10 minute warm up. Also when taking off from a stop VERY seldom, maybe 5 times in 2 months it would start bucking real bad and jumping rpms like it was running out of fuel or something, then be just fine, sometimes would lay down some white smoke when doing this.

Well tonight I was going to pull a buddy out of a ditch and went to pick them up, truck did the bucking thing when I took off from a stop sign, then getting on the highway I got up to 55/60 and it started doing the erratic boost pressure, and i started to accelerate with the cruise to pass someone and it started surging BAD, like jumping from 1500 to 2100 rpm, 0-20 pounds of boost, just bucking like crazy, could hear the turbo surging blowing air out of the air filter. So I backed off, and the rest of the 2 miles it would do this on and off, got to the shop grabbed chains and headed out and it started doing the bucking at lower speeds, so I called off helping my buddy out and came home since I am very tired anyway. It quit doing it but I'm not going to be a dumb arse and ignore this anymore lol.

So any ideas to what it could be? Tomorrow afternoon when I wake up I'll take it to the shop and check the EBP sensor for corrosion, mass air flow sensor also, I will also check the turbo for shaft play, etc but I doubt the turbo itself is bad. But other then that I'm not sure what it could be, them, to me sound like a likely culprit but I am by no means an expert. VGT actuator maybe? I don't at the moment have a scan tool to use, if it comes down to it will my buddys sct x3 that is vin locked to his 03 6.0 work to read codes, and run the gauges on my truck? ALSO NO CEL, no warning lights or anything other then trailer brake controller lol. Just wanted to make a post (sorry for the length) and maybe let a few guys bounce some ideas off each other, it would be much appreciated.

Thanks for any help, Seth.

OBS F350 · Jan 19, 2013

Bump, going to check it out in a bit.

OBS F350 · Jan 19, 2013

Had a buddy following me today and it's doing it worse now, at low speeds even and smoking white alot. Said it doesn't smell like diesel fuel, he said it kind of smells like coolant. Egr issues maybe? Possible head gasket? I already have plans to get it studded within the next couple of weeks along with egr delete and new oil cooler.

OBS F350 · Jan 19, 2013

Video of what I'm talking about: And if anyone is wondering when it's doing the issue at the beginning of the video my foot is staying in the same position until it gave it 1/2 or more throttle and it began gaining boost

http://www.youtube.com/watch?v=0oSFka0Q5Bs&feature=youtu.be

OBS F350 · Jan 19, 2013

Bump, really no one has any ideas? I'm going to remove the turbo and clean it Monday. Looks like the clamp that holds the exhaust side to the compressor side is leaking. Also I believe I have a bad egr cooler. Might do an egr delete while I have the turbo off.

Lassie · Jan 21, 2013

Map sensor/hose or EBP sensor are likely culprits. EGR and EGR throttle plate (if you have one) also. Check connections at VGT Actuator

OBS F350 · Jan 23, 2013

Cleaned the turbo tonight, was too busy last night. All the veins/unison ring were in good shape, absolutely no scorching/pitting, both turbines were good and no shaft play. I think it might be a new turbo to be honest. My v-band clamp that holds the exhaust and compressor housing together was leaking a good amount (soot all over pedistal and turbo. So I replaced it with one off of a trashed turbo I have laying around. Well amongst me hurrying to get it done I didn't realize the battery was dying in my 3/8 impact so I didn't get the clamp on the cold side boot to turbo very tight so when I left the shop I blew the boot off... No big deal 5 minutes later I was on my way, ran fine all the way home (5 miles of highway). I'll have more results when I actually get some driving time in. I do have a spare VGT solenoid off of an 03 turbo if that will work on my 05 I will swap them out next if I continue having problems.