Lost all boost yesterday. permanent limp mode

I was driving up a moderate hill in Salt Lake City yesterday and heard what almost sounded like a muffler explosion or backfire along with a big puff of smoke behind me and sudden loss of boost. I pulled over and cycled the ignition thinking I was in limp mode. No luck. Lost all boost on my gauge and turning it on and off did nothing . I've ended in limp mode a few times before usually climbing steep mountain passes so this was mystifying. All tubes and hoses are connected but a check engine light popped up with a code telling me basically I had lost my turbo. In the last 8 months I have cleaned the IM, installed gauges, removed the EGR, replaced the AT injectors with .184 MT injectors (Car originally had AT, MT installed before I bought it), Cascade Diesel did a #2 tune and the local VW dealer set the IQ after the injector swap. The car has run Beautifully since. It gets over 50 mpg with no smoke and lots of power until yesterday in Utah when we had the little explosion and lost all boost. We were able to drive 400 miles home Ok with reduced power. It drove like my 1982 MB 240D! The car has 258 K miles. I visually and digitally checked the turbo during all this recent work. It spun easily, no significant play and the actuator moved OK. I will check the actuator, the vacuum and peek at the turbo of course but what could have caused the sudden boost loss along with permanent limp mode and kicking a code? Are rebuilt turbos OK? This car is becoming a money pit and the complexity of this engine compared to my other diesels(MB, Cummins trucks, Tractors) is starting to get to me.

I’ve heard big pops when turbine wheels have exploded, and that can happen to turbos in otherwise good condition, though the ones I’ve seen do it were being sprayed with nitrous at the time

May be as simple as boost hose that came off. Check all the connections from the turbo to the IC and up to the intake and look for both oil and a disconnected hose. Also check your oil level.

Sure sounds like either you blew a c.a.c. boot/pipe off, or blew the turbo. You need to put hands and eyes on all connections and check them. Also check the tailpipe for oil. If there is oil in the tailpipe, the turbo is definitely done.

ghohouston said:

Sure sounds like either you blew a c.a.c. boot/pipe off, or blew the turbo. You need to put hands and eyes on all connections and check them. Also check the tailpipe for oil. If there is oil in the tailpipe, the turbo is definitely done.

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Thank you for the thoughts. I did take a brief look and tried to move the actuator rod which seems very stiff and just barely moves . seems like it should move even if connected? If the vanes don't move I guess we have serious issues of if the actuator doesn't actuate. The hose connections are tight and there is vacuum. Any thoughts on rebuilt vs New VNT15. I do have a junk yard VNT 15 which I am tempted to throw in just for grins but it looks like the turbo is going to have to come off darn it. The VNT 17 lokks interesting but expensive and I don't want to sacrifice economy as there is ample power for me with the little VNT15 but I would like reliability above all.

I rather doubt your mileage would drop from running a larger turbo. The mileage on my 1 ton hasn’t changed between the stock 60mm vgt, an s480, s467, or s476. Actually improved a bit since the engine wasn’t under as much load.

I don’t think you’ve found the problem. If the actuator movement was compromised, limp mode would reset when you cycle the key, at least briefly. Look at the vanes on the compressor side of the turbo, check the tailpipe for oil, and check your oil level. While checking for a popped boost hose, pull the bottom hose off the intercooler and see how much oil comes out. More than a couple tablespoons can be bad news.

The big bang and cloud of smoke sound like turbo trouble.
I would try the junkyard VNT-15 as long as it looks serviceable.

flee said:

The big bang and cloud of smoke sound like turbo trouble.
I would try the junkyard VNT-15 as long as it looks serviceable.

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Thanks guys for aLL THE ADVICE. I put it on the lift and saw all the hoses were tight. I put a vacuum gauge on the nipple and saw it would not hold vacuum and could only get a few mm Hg negative pressure. So I have a bad actuator which I assume has a diaphragm which ruptured suddenly possibly explaining the small explosion out the muffler. I couldn't remove the circlip easily and finally just broke it into several pieces with a small chisel wedging it sideways. The turbo vane lever moved easily with no friction. There is no oil so I assume the turbo is fine. My lucky day I hope. Actuators go from $12 to #150 on the net. Any advice on which are OK? Some Chinese parts are junk and some not. Country of origin is usually not mentioned.

If you want to avoid issues getting the turbo set up properly and fault codes in the future, get a genuine Garrett actuator. Garrett number is 434855 0015

hugho said:

I couldn't remove the circlip easily and finally just broke it into several pieces with a small chisel wedging it sideways.

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When you put the new clip on first tie a piece of thread or dental floos to it so when it flies off it's easier to find.
I lost a few when I changed my actuator.

Well boys, I am back. I may have to start a new thread if no one out there in diesel land is listening. My original problem was a pop explosion a few wks ago going up a hill in Utah followed by no boost and permanent limp mode. I limped back to wyoming 400 miles and put the 2002 Jetta tdi on a lift. No vacuum in the actuator so I ordered a new actuator and did a rough adjustment of the actuator, moving at 3 and maxing out at about 15 or so. Still no boost. Vacuum is low normal at 21-22. I pulled off the intake hose on the turbo and a small amt of oil came out. The turbo shaft spins and no axial play I can feel and no in and out play. I can rev engine up to 5000 rpm in neutral. MPG on the trip to Utah before it popped was 53! and lots of power.If the turbo and actuator are OK. BTW it popped a CEL. Do I need a vag com to diagnose this? Exhaust pipe has no oil and eng oil is prob OK :down a little into the cross hatch with 2500 miles since last oil chng. What is left? The N75? The MAF? Help!

IndigoBlueWagon said:

May be as simple as boost hose that came off. Check all the connections from the turbo to the IC and up to the intake and look for both oil and a disconnected hose. Also check your oil level.

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Man you called it ! I finally got around to checking the piping to and from the intercooler and yup found the problem, The hose blew off the upper intercooler pipe and jammed it into the PS pulley melting it. I am assuming that the broken or stuck actuator allowed too much boost(?) blowing out the tube from the clip. Rather than go back to stock plastic I decided to try Kerma TDI's aluminum/silicone pipes which look nicer. I hope this ends my sorry saga of life in limp mode.

Nice! Thanks for reporting back.
Seems the actuator was incidental to the problem. Bet the car runs better than ever.

I had that exact problem after putting on my 11mm pump. Thought I’d blown the turbo, drove it several days with it gutless, then when I pulled the intake to check I got looking around, and same thing, pipe into the power steering pulley. I loaded the cut with jb weld, and it’s been holding fine for now. I’m waiting for the pipe I want to come back in stock before I order the parts to build my own upper pipe.

DMan1198 said:

I had that exact problem after putting on my 11mm pump. Thought I’d blown the turbo, drove it several days with it gutless, then when I pulled the intake to check I got looking around, and same thing, pipe into the power steering pulley. I loaded the cut with jb weld, and it’s been holding fine for now. I’m waiting for the pipe I want to come back in stock before I order the parts to build my own upper pipe.

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Same thing I did using JB weld.
A few years later the patch cracked and I ground it clean and added more on top of the original repair.

I mustn’t’ve cleaned mine well enough before applying the jb weld, as it weeps oil a bit.

Glad you found your problem