Removing the Turbo - Polo 2DR 2006 1.9TDI

I was watching the myturbodiesel videos that claims the Borg Warner Turbo actuator works in reverse, ie it pushes!?

This had me confused somewhat so I've been downstairs rebuilding the VNT on my turbo and from what I see, the actuator doesn't push it pulls which from a vacuum based system makes a lot of sense. I'll take some pictures or make a video to show how it works and on a good note, having seen the hot side, the vanes are happy and free, there doesn't seem to be too much damage on the VNT system at all. So depending on how the bushes work ( I think they might be pressed in ) and if I can get the giant clip off on the pressure side, there might be a slight chance of a rebuild.

Pics coming soon...

I think the reverse function is in the electronics of the VNT control. There was a discussion here several years ago. That is why a Garrett smart actuator will work physically on a BW turbo, but with a constant CEL. The one I installed on my Golf pulls down on the VNT lever when vacuum is applied. I watched it with a vacuum pump to make any necessary adjustments.

JB05 said:

I think the reverse function is in the electronics of the VNT control. There was a discussion here several years ago. That is why a Garrett smart actuator will work physically on a BW turbo, but with a constant CEL. The one I installed on my Golf pulls down on the VNT lever when vacuum is applied. I watched it with a vacuum pump to make any necessary adjustments.

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There's also videos showing the connection is using an e-clip, anyone trying to disconnect the actuator arm that way will be there for a very long time. I think you have to remove the nut



I had a suspicion that my Turbo was under and over boosting, so decided to have a closer look at how the BW39A works and see if I can notice any difference between it and the BW39A 0019 that was on there. I haven't...

But I have learned a little more on how the VNT works so there's a MityVac on order so I can also check and measure the Vac Solenoid Block to see what it's doing too.

I've been wondering whether there's an EGR and VNT relationship going on. If the vanes close to accelerate exhaust, I assume the EGR system might relieve some exhaust pressure so the engine doesn't stall.






Im also trying to get my head around how the vacuum system works as it's a vac pump that works on RPM and not manifold... so that raises a few more questions which help work out what the ECU has to do to make it work.

Once I have the MityVAC I'll be checking the vac system more thoroughly, it's the only way I can see the ECU having some control over the vacuum and boost / EGR control

The N75 solenoid controls the vacuum. The engine vacuum is a constant 25+ which the N75 solenoid regulates to the turbo actuator depending on engine load that the ECU reads.
My BW turbo has a different linkage than what you have pictured. No C clip for one. I had to lengthen the rod on the replacement Garrett actuator to adopt it to the BW turbo.

JB05 said:

The N75 solenoid controls the vacuum. The engine vacuum is a constant 25+ which the N75 solenoid regulates to the turbo actuator depending on engine load that the ECU reads.
My BW turbo has a different linkage than what you have pictured. No C clip for one. I had to lengthen the rod on the replacement Garrett actuator to adopt it to the BW turbo.

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Thanks for the JB, my MityVac should be here any day now and I'm going to check all of them and will post. The connection to the vac pump doesn't feel rigid, so will take advantage of the gauge and ensure everything checks out before I try anything else.

My wife took it to work, it didn't blow smoke, so now it may have been a MAP. I've been looking at my logs and the Specified and Actuals seems to correspond with throttle and RPM, so maybe the MAP clean helped, but I've got turbo lag and hesitation and none of that can be solved without a good vac control system and logs do show small peaks of overboost @ 2.5 bar and I thought 2.1 was max... will check again when I know VAC system is healthy

As for the linkages, both the Borg Warners I have here have the same linkage system. Turbo was replaced once before so not sure if that's how the genuine from South African build come to Australia. Just saying to be sure some poor sod doesn't spend an hour trying to remove a e-clip blind!

Check - in.. update...

I've been for a long drive and there's no sign of over fueling or smoke, just the tell tails signs of oil burning in the pipes. The smoke stopped once I cleaned the MAP and intercooler.

My MITYVAC didn't arrive, spline drives did so I can do some other things while I wait. There's still a huge boost lag and hesitation, if I keep the revs up I don't lag, so checking the vac, actuators, vac solenoid valves and vac pump are still pending.

There is however a new issue that's arisen. There's an intermittent harsh rattling sound, makes me think of Jarheads pointer about not tightening up the EGR flanges so will check them but I dont think that's it because I did tighten them thinking about his pointer..

When the rattle begins there's a total loss of boost power. I've considered the Dual Mass Flywheel, though it never happens in first gear. It's usually in longer gears, 3rd and fourth.

If I were to take a wild stab at it, it seems the FLAP servo is going nuts and blocking off the air, but there are no faults on the dash. Will hook up vag com soon and check.

Please... please... please be true

POLO Mk4 9N Heater Core replacement

https://workshop-manuals.com/volkswagen/polo-mk4/heating_ventilation_air_conditioning/heating_air_conditioning/heating/heat_exchanger_remove_and_install/heat_exchanger_(behr_box)_remove_and_install/removal/

blis said:

Check - in.. update...

I've been for a long drive and there's no sign of over fueling or smoke, just the tell tails signs of oil burning in the pipes. The smoke stopped once I cleaned the MAP and intercooler.

My MITYVAC didn't arrive, spline drives did so I can do some other things while I wait. There's still a huge boost lag and hesitation, if I keep the revs up I don't lag, so checking the vac, actuators, vac solenoid valves and vac pump are still pending.

There is however a new issue that's arisen. There's an intermittent harsh rattling sound, makes me think of Jarheads pointer about not tightening up the EGR flanges so will check them but I dont think that's it because I did tighten them thinking about his pointer..

When the rattle begins there's a total loss of boost power. I've considered the Dual Mass Flywheel, though it never happens in first gear. It's usually in longer gears, 3rd and fourth.

If I were to take a wild stab at it, it seems the FLAP servo is going nuts and blocking off the air, but there are no faults on the dash. Will hook up vag com soon and check.

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I went out for a quick run with the EGR flap disconnect.. Had no lag, no hesitation and no RATTLE... I will go out for another longer run this evening,

blis said:

I went out for a quick run with the EGR flap disconnect.. Had no lag, no hesitation and no RATTLE... I will go out for another longer run this evening,

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Looks like you’ve found you’re problem. New? Used? Replacement.

As far as the heater core I have not had to do one of those yet. I’ve had to repair the blend doors on my daughters 01 Bug which you can do by removing only a few pieces of the dash. However her blend door support pin was also bad and I managed to bend the flange that fits into the pin so I’ll be taking her heater box out to get at that.

You really have done a great job on removal and replacement, diagnosing more than one issue and fixing each of them.

Thanks Jarhead, your support has been welcomed. It's horrid when you are questioning yourself with doubt and always helps to have someone to discuss things with..

Im not sure what I'm going to do with the EGR flap, (throttle body as some call it) but it's not a throttle body at all. Personally I'd like to leave the EGR valve in place, if I can disable the FLAP and keep the ECU happy, that will be ideal. I've got a sneaky suspicion that the MAP sensor and the EGR flap work together as it's the only way I can think of to determine if the flap is actually working, because there will be a slight pressure increase if the flap closes to create the lower pressure in the intake manifold to draw out the gases via EGR valve. It may just be a resistance check on the FLAP servo, it that's the case, I'll remove the flaps and leave it be. Not really sure what will and wont work. The someone in Victoria that has a few spare lying around the shop from EGR deletes, I don't think it will be hard to find one. Also haven't checked the wiring to the FLAP either, who knows... BUT THERES NO HESITATION and NO RATTLE and plenty of boost AND.... NO SMOKE!

I was concerned it was my turbo... but the sound was a constant frequency and turbos aren't.... I'm relatively happy!

As for the heater matrix, I'm almost there... I'll take some pictures soon and add it to this thread. I haven't had any responses at myturbodiesel, so everything I find, I'll post here. It is a DASH IN job!! Wooohooo!

Myturbodiesel is a great site, and a great resource, things are laid out well and fairly easy to find, but not a lot of activity like this site has.

People are always doing egr deletes so you’re right it should be easy to find one laying around.

Since I’ve got to get into my daughters bug to fix that support pin I’ll be following your heater core/matrix experience. I really have enjoyed the awesome pictures you’ve been taking.

You win some, you lose some!!! The Turbo actuator checked out right on the money at full retraction 18in Hg. I was pleased to know it wasn't the cause of any of the issues. Then I took her out for a drive, Air bag light on from heater core fix, no big deal. No hesitation, WOT 3rd gear, no smoke... Feeling great and heater working, too!!

Then pulled over, restarted her, gave the son a drive, and wouldn't ya know it.. THAT NOISE IT BACK (2 seconds max) and there's NO POWER, it stops and then everything normal again, boost and heaps of power. The noise is always a constant rattling sound, doesn't change in frequency... *stumped*

We can't work out where the noise if coming from, I'm always doubtful of myself, but I don't think it's the turbo, it's certainly not the EGR flap, there's no hesitation, the only thing to try is remove the EGR valve vacuum line, maybe the actuator there is fubar...

Otherwise it might be injectors, transmission, clutch??? Really not sure.. will be really bummed if I have to go under it again!

I'll try and get some video footage of the sounds, it's hard to describe other than calling it a loud rattle....

It's ok, I own a MK2 ABF, I'm well versed in recovering from failure...

The car has been driven for a week now, the shudder/rattle noise hasn't returned, engine boosts fine, there's no lag and she's running like she always did.

The EGR Flap / Throttle body is still disconnected. I like the idea of having the EGR valve still there to release exhaust pressures and not have the EGR valve get in the way. Maybe the ECU is learning, maybe a fresh tank of fuel helped, maybe the injectors needed a purge... who knows, but for now the two most significant changes still remain the MAP clean, pressure duct o-rings and the disconnection of the EGR flap.

I'll reconnect the EGR Flap once I've had a 1000Km of no problems before I plug it back in. Might help narrow down the issues.

There's mention in the depths of TDIForums of a 1K resistor cheat for the EGR flap. I'd rather have it open and I have no problems with leaving the EGR in place too, if the exhaust manifold pressure is high enough to pop the valve I'd rather some of it escape. Im having no engine issues leaving the flap open either. From what I've read, it's supposed to lower the intake pressure but there's no sign of poor combustion without it.

I'm enjoying a champagne period before I reconnect the FLAP and wife has no problem whatsoever ignoring an engine light

A week or so later..

We've been running for a week now with no hiccups or lag. The IAC/THROTTLE/EGR Flap remains disconnected. Pondering over the rattle and lag and perhaps a membrane in the EGR actuator or some debris in vacuum systems, who knows...

But she's running like she always has, Im not sure if our temperate climate helps, but I'm not sensing an over-run on the engine like I do with my gasser that needs an ISV. At some point I'm going to reconnect and see if I can isolate the issue.

If it was a vacuum system problem, perhaps it's gone away. the likely cause could have been the EGR valve oscilating on and off but that hasn't recurred for a week.

Stay tuned...

Good to hear it’s been running well. With all the time and money it can be frustrating if things don’t work out.

It's been a month now and it's been all good with the ASV/ISV/Throttle disconnected. I plugged it back in the other night to check . Once again there seems to be a fault in the valve as it seems to close and block intake air and chokes the engine. Disconnected it and everything was fine. CEL but hey, it runs. I may get around to swapping the ISV/ICV valve if I get an opportunity to get one cheap.

I found a very clean, used one on e-bay a few years ago.

JB05 said:

I found a very clean, used one on e-bay a few years ago.

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I assumed with all the EGR deletes, they wont be too hard to find. For now not in any hurry... My wife hasn't a problem with a CEL

Just keep your eye open, as you said with all the deletes they shouldn’t be hard to find, or someone parting a wreck. CEL lights bug me but for most as long as the car passes inspection and drives well it’s all good.

Great job on all the work, I liked the way you documented everything.

Tdijarhead said:

Just keep your eye open, as you said with all the deletes they shouldn’t be hard to find, or someone parting a wreck. CEL lights bug me but for most as long as the car passes inspection and drives well it’s all good.

Great job on all the work, I liked the way you documented everything.

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Thanks for the support TDIJarhead... It's been running like a treat with the ISV disconnected, I waited a few week before trying to reconnect the valve to be certain and the moment I connected it, the car choked up again.

Not sure if I mentioned it, but prior to disconnecting it, I saw the intake rubber section expand like a balloon under boost which is what made me think somethings wrong (might have acccounted for air/fuel mix too) and I disconnected.

Im in no hurry to rectify the problem because we're not selling the car. The EGR is still connected and I'm ok with that

PS: I'm an old IT guy, in the days of BBS where you had quotas to upload as much as you downloaded. They were the good days where information was free, but not there to be stolen. It doesn't take much to grab a few photos and write a progress report.

Without all the other like minded people, there'd be only questions without answers and I really don't like forums with countless threads that lead up to a solution and then stop...

I'm sure there'll be a word in the English dictionary for that now, or in the near future

Update: Found box aluminium, removed gasket from EGR flange, made new solid gasket from Alu and forgot the hole.... I simply couldn't drive the car without blocking the EGR. The valve would make a horrible sound if I applied too much load and it would bog down. Assumption: The EGR valve is allowing too much bypass of inert exhaust back into the intake and richens up the mixture till it bogs down. So I've blanked the EGR port, reconnected the IAC/Servo flap and engine light is and feels like its in limp.

Will find out more.

It's running and thats all that matters for now.

Always good for the engine to eliminate those nasty gasses from the EGR, normally needs tune to make ECU happy.

Here's an update...

I eventually blocked off the EGR with a plate and the car almost immediately went into limp mode. How the system knew the EGR failed is a conundrum, as it's all vacuum driven, but we ran with it for a couple of months anyway, no big deal.

The limp mode would kick in with the A/C and I'd been contemplating a small hole in the plate to bleed some gases so I looked up online and many said a 7mm hole would do the trick, and it did.

Drilled out a 7mm hole, within a few minutes the engine light went out and no more limp mode. The car does puff a little more unburst but combusted deisel on take off, but nothing like the rich state it was.

I have to conclude that the EGR has failed and I'll be keeping an eye out for a cheap replacement (as many delete them) and will continue to use the restrictor plate in future.

One thing did come to mind, one of the flanges had a metal gasket and Im unsure if it was a restrictor to start with, so that could have been the cause of the EGR valve bouncing/failing/rattling.

All good for now,

cheers

h

I have a spare sitting on my shelf, loaned it out a while back to another member helping him sort out an issue with an 04 PD Beetle.

Maybe I should just hop in the golf and drive over, we’ll hook it up and see if it helps. That would be a trick for sure.

Tdijarhead said:

I have a spare sitting on my shelf, loaned it out a while back to another member helping him sort out an issue with an 04 PD Beetle.

Maybe I should just hop in the golf and drive over, we’ll hook it up and see if it helps. That would be a trick for sure.

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Unless it floats and has props, it's a long way across the Pacific


A few days on and no engine light or sounds/signs of any major issues. Any thoughts on how the system knew the EGR was blocked?

I’ve been following your ups and downs on this. I find it interesting that a 7 mm hole did away with limp mode and the engine light. I’m not really sure why.

I’m chasing a problem with my PD I think I’ve narrowed it down to a cracked intercooler. I’m going to have a look this morning. I have a spare intercooler but it’s for an alh not the PD BEW my 05 has.

The EGR is activate by vacuum from the vacuum solenoid block (I think). The throttle body, flap, choke or whatever you wish to call it on a diesel is said to manage the intake pressures to help with the flow into the EGR etc.

One could assume an O2 sensor on EGR actuation might pick up the change or the vacuum system or solenoid has smarts.. who knows!

Goes well though, so I haven't any probs and it holds it own against a 3Dr GTI Polo the wife bought herself