Turbo failure diagnostic

Hi all!
My engine has eaten 2 turbo in the last week, and I'd like some feedback as to how and why.
The car is a 1999 B5 passat syncro with a 1.9 TDi AFN engine, just rebuilt, from bottom to top. Same old turbo, but upgraded nozzles .260 from darkside, egr delete. Straight pipe. That's all I can think of currently.
I'm guessing it's a nobrainer and it's overspinning, but I'd like to get some expert opinion on the matter. Engine works well and still cranks after both occurances, oil in intercooler.
Acctuator calibration is questionable.
Here's some photos of the turbo remains.
https://imgur.com/a/ogI6ABK

How's the oil flow to the turbo? If it's not getting good flow, that will kill them quickly.

And yes, an over speed could also cause them to go like that too.
There's a procedure to calibrate the turbo actuator. I have done it before, but don't remember the specifics.

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Flow should be good, I've got a oil pressure gauge, it's a little low for my liking, but decent, 0.7-0.9 bar on hot idle, and a little lower than 1 bar per 1k rpm
Will be removing the oil feed and spraying it clean, just in case there is some gunk in it.

Is that at the oil filter? I've got over 1.7bar at hot idle on my bhw...

What's your oil drain look like? Needs to be fairly straight and no inhibit flow

A newly rebuilt motor should be better oil pressure than that! Was the oil pump replaced? Were the bearings replaced with the correct size? I'd recommend putting a mechanical gauge on the oil pressure to verify, and if it's low, fix it before it takes the rest of the engine out with it! The turbo generally takes the first hit with low oil pressure.

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Spec is 2 bar at 2k rpms

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Oil pump replaced with aftermarket, bearings checked by a local machine shop, green light from them.
I've got 1.9 bars of oil pressure at 2k rpm, the gauges accuracy is somewhat shady tho, I'll be getting a machanical one. It's measuring at the oil filter. Going to take a photo when I get of work. Would it be an idea to check pressure at the turbo feed? I've already got the turbo off, so I can remove the feed line, and put a gauge there.
1.7 at hot ilde, damn, id love to get those numbers. Maybe I should drop the pan, and install an ABA oil pump? I hear those have a higher gearing.

Ferdrever said:

Oil pump replaced with aftermarket, bearings checked by a local machine shop, green light from them.
I've got 1.9 bars of oil pressure at 2k rpm, the gauges accuracy is somewhat shady tho, I'll be getting a machanical one. It's measuring at the oil filter. Going to take a photo when I get of work. Would it be an idea to check pressure at the turbo feed? I've already got the turbo off, so I can remove the feed line, and put a gauge there.
1.7 at hot ilde, damn, id love to get those numbers. Maybe I should drop the pan, and install an ABA oil pump? I hear those have a higher gearing.

Click to expand...

I have a balance shaft delete with an Alh pump\gear. I don't have a very high end gauge but it reads about 25psi at idle and above 40 when driving around usually. Not sure if it's super accurate ?*

Yea, I'd like a geared oil pump instead of my intermediate shaft, but what can you do..
Anyhow I've got some photos of my oil filter housing, and where I am tapping in for oil pressure,I belive it is not the high side, but could be wrong.

http://imgur.com/gallery/GCVWCkm

Will try to hook a gauge up on the turbo feed next.

Ferdrever said:

Yea, I'd like a geared oil pump instead of my intermediate shaft, but what can you do..

Anyhow I've got some photos of my oil filter housing, and where I am tapping in for oil pressure,I belive it is not the high side, but could be wrong.



http://imgur.com/gallery/GCVWCkm



Will try to hook a gauge up on the turbo feed next.

Click to expand...

Oh yeah, so I guess your engine is basically the same as our ahu engine... Do you know if the intermediate shaft bearings were replaced?

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Mozambiquer said:

Oh yeah, so I guess your engine is basically the same as our ahu engine... Do you know if the intermediate shaft bearings were replaced?

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Click to expand...

They were not replaced ?

Ferdrever said:

They were not replaced [emoji848]

Click to expand...

Hmm... Yeah, as I understand, that's one of the biggest causes of low oil pressure, it'll be a loss of oil volume mainly.

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Aight, low oil pressure was a false alarm! But I switched the bearings anyway. All good now, inaccurate sensor.

BUT!
I am experiencing something wierd, not sure if this deserves its own post..
I am able to create a backfire, for some reason.. Anytime I'm over 2k rpm, and I lift of the throttle for ~2 seconds, and try to accelerate, nothing happens, white smoke comes out of the exhaust(I'm guessing diesel) . And if I keep holding the throttle down, I get a really loud backfire.. This only happens above 2k rpm, never under. If I clutch in and out quickly, while above 2k rpm, the car accelerates normally, I have to release the throttle for ~2 sec, above 2k rpm for it to happen.. Any input as to why?

I've got a video link, and please I only want discussion about the backfire, and not the black smoke.

https://drive.google.com/file/d/1KFqfIERfwAxoGEx3XlsCiTOtuJNcgz0U/view?usp=drivesdk

Most failures are caused by the three 'turbo killers' of oil starvation, oil contamination, and foreign object damage. More than 90% of turbocharger failures are caused oil-related either by oil starvation or oil contamination. Blocked or leaking pipes or lack of priming on fitting usually causes oil starvation. So, you should control all these details. I don't know how others but I have a diagnostic device from thinkdiag.co.uk that helps me to make a fast diagnostic of my car when it has problems. It saved a lot of time and money because it found quickly where were the problems.

When I look at the pictures of the COLD SIDE, that's not caused by oil starvation...... the compressor wheel looks like it was used on a blender, or swapped over to the HOT SIDE and it melted.

What did you suck through the motor to do that kind of damage to the wheel?
Based on the video, you're also overfuelling, so you're killing your oil and thus it's ability to lubricate as a result.
The backfires are causing massive shock (among other things) to your snail.

What are your EGTs like?