SOLVED(Intermittent vacuum loss at pump nipple) : Pop like I blew a turbo hose - no boost leak problems with intercooler piping

[bhef]

Hey all,

The other day when leaving for work, moving maybe 3MPH in first gear, I heard a loud pop sounding like I blew a tire. Checked the tire front right where the sound came from and all was well there. Called the PO and he told me this was probably a turbo hose getting a hole or coming off when I mentioned that my turbo and power is weak compared to before the pop happened. My gas mileage has improved considerably, however, I now smell exhaust when the car idles way more than before(maybe related?)

I have a VNT 17/22 and tune from KermaTDI. Have the 3 bar MAP sensor. Also, EGR deleted. No shudder valve either. Only about 40k miles on all of these components.

No CEL.

I've checked all of the intercooler piping/turbo hoses and even replaced the turbo hose right out of the hot side of the turbo as it was starting to be in bad shape. No changes in boosting after replacing. Everything else looks great. Made a DIY boost leak tester and when pressurizing the only thing that was leaking was the hose on the intake to the turbo. Tightened the clamp and that's better now. Helped startups go more smoothly, but still having power and boost issue.

I recently purchased a Ross-Tech OBDII to USB. When checking the MAP today it flatlines and won't go above 255 kPa or 2.55 Bar like stock would. All the sounds of my turbo are still there at the same timing corresponding to RPM and pedal position except quieter and the powerband feels like it's in the same places relative to RPM except weaker. Smokes a little grey smoke under WOT just the same too.

Does the VCDS program pickup on levels of MAP readings above stock? In other words, would it read boosting above stock when a tune is applied to the ECU with an upgraded MAP sensor?? Can a tune go bad and cause the ECU to revert to stock MAP settings?? What could that pop sound have been?!

I'm at my wit's end here. I've had this TDI for about 6 weeks and am relatively new to checking the turbo and associated components. Where to start and what to check would be helpful.

ANY insight/direction is GREATLY appreciated.

Please help me get this TDI back to it's great performance.

 

[MukGyver]

Not sure what type of egr delete you did but I would check everything that still flows exhaust gas thru it before the turbo including bellows and flex pipes. You heard pop, smelled exhaust, and lost power, there are three big clues right there. are you running a cat... potatoe in the tail pipe?

 

[bhef]

I now believe the pop sound was the actuator for the turbo vane adjustment failing. It's done. Maybe it gave out and changed the vanes so quickly when it failed that the difference in airflow resulted in a noise?? Who knows...either way, a limp mode fix kit from KermaTDI is being ordered so I can freshen up the systems surrounding the turbo's operation in addition to replacing the actuator.

 

[snakeye]

Never heard of the actuator making a noise like that, but who knows. Did you check it to see if it's bad? A popping sounds can also be a blown turbo...

 

[Tdijarhead]

Are you blowing white smoke out the tailpipe?

 

[Curious Chris]

X2 on checking the turbo. When my stock turbo compressor wheel broke off it was a pop. I had a boost gauge so I new something bad had happened. Yes VCDS will show all data. Just for giggles try this: logging Actual MAP, Specified MAP, Actual MAF, Specified MAF, and throttle position; full throttle 2000 rpm to 4500 (in a gear where you can get 15 seconds) repeat 3 times. Send data to me.

Black smoke?

 

[bhef]

Are you blowing white smoke out the tailpipe?

no white smoke

 

[bhef]

X2 on checking the turbo. When my stock turbo compressor wheel broke off it was a pop. I had a boost gauge so I new something bad had happened. Yes VCDS will show all data. Just for giggles try this: logging Actual MAP, Specified MAP, Actual MAF, Specified MAF, and throttle position; full throttle 2000 rpm to 4500 (in a gear where you can get 15 seconds) repeat 3 times. Send data to me.

Black smoke?

with this large turbo, larger nozzles, and the tune it would throw some black smoke if I floored it at 2000 rpm regularly. If i roll into WOT from 2k and by 2500 with full throttle it only does a little grey smoke but not much. Same now but less smoke. Ill hook up VCDS and send the data. I'm not quite sure how to log it yet but Ill do my best to figure it out.

 

[bhef]

No detectable shaft play whatsoever and the fins of the turbo look immaculate. I'm happy about that at least. I'll post pics tomorrow. Also, time allowing, I'll run the log of MAP/MAF/throttle.

 

[BobnOH]

For logs, there is this from Malone (Actions>/Upload). Or you can roll your own using this handy program from member JollyGreenGiant.
The Malone app may be easier to share, simply upload, plot, link page back here. The other you would need to upload a pic (eg Snipping Tool) to the forum (tricky the 1st time) then link to that. Advantage is it stays forever.

 

[eddieleephd]

Egr deleted meaning it's been removed completely, or it's still there just not operating? If it's still there, the diaphragm can blow and leak.
One of my old intercoolers had blown and resulted in similar results. Also the small hose between the intercooler and the upper pipe is difficult to inspect. It really needs to be removed and inspected.
The intercooler is easiest to inspect if you removed the bumper cover, easier to replace also.
Removing the washer fluid reservoir makes the boost hoses easier to access without a cable clamp tool.

 

[bhef]

Egr deleted meaning it's been removed completely, or it's still there just not operating? If it's still there, the diaphragm can blow and leak.
One of my old intercoolers had blown and resulted in similar results. Also the small hose between the intercooler and the upper pipe is difficult to inspect. It really needs to be removed and inspected.
The intercooler is easiest to inspect if you removed the bumper cover, easier to replace also.
Removing the washer fluid reservoir makes the boost hoses easier to access without a cable clamp tool.

The PO took an EGR, bored it out and then blocked everything off from it to look as if there was functioning EGR there for smog check purposes. It's a visual inspection in CA. This leaking may be the case and I'll check it out. Thanks for the idea.

I have a center mount intercooler and the hoses are very hard to inspect at the intercooler, but after a lot of work I got to checking them out and they seem fine.

 

[bhef]

Here are some pics of the turbo blades. I had to take a video and then screenshot as it was not easy to get a phone up in there and snap good pics. Please excuse the lack of ideal pic qualities

 

[bhef]

For logs, there is this from Malone (Actions>/Upload). Or you can roll your own using this handy program from member JollyGreenGiant.
The Malone app may be easier to share, simply upload, plot, link page back here. The other you would need to upload a pic (eg Snipping Tool) to the forum (tricky the 1st time) then link to that. Advantage is it stays forever.

Thanks for the suggestion. Hopefully I make time to log soon. I am currently restoring the wire harness on my truck and need to get that done by tomorrow

 

[bhef]

Curious, could a dirty fuel filter cause a decrease in power like this without stumbling or hesitation?

I have new fuel lines for under the hood coming in tomorrow. They are visibly cracked and I wanted to wait until I could change them before I replace the filter.

The filter itself only has 10k-14k miles on it, but that was over the course of multiple years as the PO is retired and rarely drove it. I just remembered today that he had a similar problem with power and said it took about 30 miles of driving for power to fully come back when getting it ready to sell to me in the days before purchase. He actually gave me a new fuel filter in case this was the issue when he sold me the car.

 

[eddieleephd]

The sudden loss of power tells me there's a boost leak.
Literally, pop! Loss of power, is a boost leak happening.
A hole in a hose, which can be hard to see without removing and inspection. Perhaps another component blowing a hole such as the egr valve, or intercooler.
Really is the only thing that it can be. Hopefully it's the egr valve and a simple fix rather than the intercooler.

 

[wonneber]

Did you scan for codes?
Motor should be up to temperature. (in vcds, not just on the gauge)

 

[bhef]

So this is a little embarrassing...The pop I thought I heard was a bad ball joint on my passenger side popping back into place after moving the tire to check for play when jacked up. It has done it 3 times now and they all sound exactly the same and happen when turning around my garage in the same place after checking wheel play. A POP that rings out through the tire causing it to sound different than just metal on metal.

Turns out my loss in power was coincidental to the sound.

Found a vacuum leak in a plastic connector going to the actuator for the turbo when the engine is warmed up. Once that was fixed the actuator now holds 20mm Hg no problem and moves at 3mm and stops at 18mm. From this connector replacement I got a return of power, but not yet 100%. After one day of driving it was right back to lower power again.

I tested the vacuum right off of the brake booster line with engine idling and it was initially 26+mm Hg and then started jumping wildly around 15mm Hg after some time. I almost missed the loss in vacuum. When pressing the brake booster line into the vacuum pump it stays solid at 26-27 mm Hg. Upon further inspection it is obvious the nipple of my vacuum pump is incredibly loose and a loss of vacuum is occurring there intermittently.

I put some 1 min gasket maker all around the base of the nipple and let it fully harden all day. After next start up it holds vacuum fully again. Full power restored.

It seems the power has gone down some to about 95%. Maybe the vacuum is leaking there slightly again after some driving.

I'll be checking vacuum from the pump again and reapplying more gasket maker if need be until I get a new vacuum pump in the mail. It appears I have a slight oil leak from the pump as well and I'm just going to buy a new OE one to solve all issues surrounding it. I'll have a spare as backup as well, which I can do the JB Weld fix to seal the nipple and get replacement gaskets to ensure I can appropriately deal with this problem again should it ever arise in the future.

Thanks all for the comments, opinions, suggestions, etc.

 

[bhef]

Did you scan for codes?
Motor should be up to temperature. (in vcds, not just on the gauge)

Never any codes in VCDS with engine fully warm per VCDS readings.