[Werdna]

Hi,
Wonder if anybody can help with takeoff power issues. Have had them a while and just dealing with it. Car is a 2006 Jetta MK5, manual TDI, BKD engine. Its got to the point where I don’t trust the car in the hands of others due to its hesitation. Particularly noticeable taking a corner in second gear if you let the revs drop or trying to enter traffic quickly from a rolling start. Its great once the revs are up. There are a few threads that reference a low power FAQ but the links to that are dead.

Had an EGR valve replacement when diaphragm failed (low EGR flow fault), got the intake manifold cleaned at the time and since then done the following to try to nail down this issue to no avail:
1. Swapped vacuum control solenoid block to confirm it was not the culprit.
2. Replaced all vacuum control lines (complete spider) from solenoid block to turbo, EGR, intake, vac reservoir etc.
3. Changed the MAP sensor
4. Tried a chinese turbo for a test before reverting back to the Garret.
5. Changed leaky boost pipe seals where oil mist seepage was obvious.
6. Checked VNT actuator with a mighty-vac for expected operation.
7. Replaced the HP fuel pump which was wearing.

I‘ve T’d in a vacuum gauge at the EGR control vacuum at this 1000 RPM flat spot the vacuum is switched in (as expected) but it feels under-fuelled, backing off on the pedal till the EGR winds off it then feels like a sweet spot is struck, RPM climbs and you can slowly ramp in the pedal for normal acceleration. In essence full throttle at 1000RPM it chokes. Mechanic recommended HPFP replacement which had no impact. It seems to me that the ECU underfueling when EGR is open. Maybe this is normal for these cars in a manual. ECU details below.

Can anybody tell from below whether I have the latest BKD ECU software?

Can anybody tell me what EGR cooler blocked symptoms fee like?

Any other ideas I can chase down would also be greatly appreciated.


Address 01: Engine
Labels: 03G-906-016-BKD. clb
Part No SW: 03G 906 016 FM
Hw: 028 101 190 3
Component: R4 2, OL EDC GO00SG 7287
Revision: 12345678
Serial number: VwZ7Z0E3111987
Coding: 0000072
Shop #: WSC 41449 002 1048576
VID: 73CB25F212C74013CE-8026
No fault code found.
Readiness: 0 0 1 1 1

Cheers,

A

 

[Moonshot Rattle Bucket]

Hi Werdna, dropping these links here for you while you're waiting for some help to chime in. Also, it looks like you may have vcds. If so, you should post all those results and folks can get some clues to run with. If you don't have a vcds that is really something you might consider.

These links and more, are live, I found putting in 'low power BKD engine' into the site search above.

https://www.myturbodiesel.com/threads/diagnosing-and-fixing-low-and-no-power-constant-low-power-and-cant-rev-high.36083/#post-169929

https://www.myturbodiesel.com/threads/less-common-and-rare-causes-of-low-power-and-how-to-fix.2280/#post-15987

Low power + Smoke, Fixed when MAP sensor unplugged

My BRM engine is acting up. Initially I experience very low power up to ~2000 rpm then a hesitation before the turbo kicks in and blows smoke. If I unplug the MAP sensor the car runs smooth, with low power (no turbo). I have checked: Cam, looks good, virtually no wear VNT actuator moves as...

www.myturbodiesel.com

06 Jetta intermitant problems low power

Hi I want to thank all you guys for all your help so far in helping me thus far. I posted this in another forum First a little history on car and problems. History: Bought car new (My MAJOR mistake!) 06 Jetta TDI 5sp Warranty replaced Clutch/flywheel assy., MAF sensor, EGR cooler 3 times now...

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Low power off idle

Hi everyone, new to the site. I just finished installing a new camshaft and tb along with deleting the egr valve and egr cooler. I had the ECU reflashed with the egr delete. Stock power. Now I have a cel with P0122 code and the car has a lot of hesitation off idle. When I deleted the egr valve I...

www.myturbodiesel.com

 

[Werdna]

Thanks for the links Moonshot Rattle Bucket,

I have finally got to uploading the scope from VGCS today. I tried uploading the raw data but file extension CSV or LOG is not allowed. It’s pretty clear that EGR kicking in is related. Backing off and getting the EGR to back off too starts to get things happening. WIth foot to the floor it is very painful off the mark. There is no fault codes being listed in VGCS.

I have replaced MAP and MAF along the path so sure I don’t have a sensor problem. Every vac line is replaced.

It feels a lot like EGR kicking in causes turbo to not spin up. There is a bit of traffic out there on EGR delete and zip-tie mods. Can anybody shed any light on the theory behind what is happening if actuator stop is not adjusted? ….. Or am I just seeing a tired/carbon affected turbo and actuator stop adjustment would just be trying to compensate for that?

Any advice appreaciated.

 

[Moonshot Rattle Bucket]

What you really want to be able to do is compare requested boost vs the actual boost. That would graph the turbo performance for you and give you an idea what's happening. The egr if stuck closed shouldn't cause sluggish boost and anyway you say it's been replaced.

You could have a place in the vnt range that isn't being reached from sticking vanes, such as at the beginning of spooling up causing the delay. The vanes close down to a tightly focused opening stream at the beginning to get the spooling going as soon as possible. It could be the vanes mechanically can't reach that point because of crud buildup etc. You do finally get boost to build up so that leads me to think the n75 and the vacuum lines are probably okay at getting vacuum there.

Another thing is the actuator's adjustment which affects when boost comes on. How to check for that is up in those links I sent.

Good luck!

 

[Werdna]

Hi,
I’m back again. Same thread, same car, same performance. I’m wondering if anybody has had a clogged catalytic that has been the culprit for low power on takeoff?

Have been over the car many times on the boost side, replaced the seals in the intercooler piping, dismantled turbo and cleaned the vanes, put a new (Mellet) turbo core in….. no intercooler pipe leaks detected, no change from any work done so far. I have swapped my vac gauge to the turbo actuator and it looks like it is near fully activated at idle (vacuum of 25 in Hg)… nowhere to go to get more boost so no takeoff air to spare. Control all looks normal once I get the revs up to > 1500, does not want to take off if I ask it to with the revs below 1500rpm, standing start needs 2000rpm to get going off the line. Trying to go around a corner and letting the revs in 2nd gear to drop to 1000 it just chokes and does a very slow climb out of bed until it reaches 1800rpm.

I’m working on the theory that the catalytic converter is blocked so turbine won’t get good enough flow at idle to get to the desired boost. Anybody had success with cleaning catalytic converter / exhaust that resulted in better takeoff?

2006 Jetta, manual TDI, no DPF.

A

 

[Moonshot Rattle Bucket]

I've had great success with a rod and a hammer.. don't ask me to elaborate.. then again I live in a no-smog county.

 

[Werdna]

Ok. I’m guessing that’s to reverse the pressure up the pipe which eases the restrictions. Hard to see an easier method. ;-)

 

[Werdna]

This week I have used oven cleaner on the catalytic converter with two doses and high pressure washer and I have to say it’s a great improvement. Much smoother power and coming in at lower RPM. If anybody has any tips on how to properly clean / which chemical works best I would really appreciate the help.

 

[Moonshot Rattle Bucket]

you could try sticking it in a bucket of strong laundry detergent and water overnight then rinse and blow it out the next day.