Significant Hesitation At Speed

[dieB4sel]

TDI friends,
First off, I must admit I am a novice…hopefully I can put together enough information for an informed discussion. The last few months my 2005 TDI Passat has had a hesitation/lurching issue. This is generally felt most significantly at speeds of around 50+ MPH while going up a grade, not in a passing gear. This issue has been going on for a few months now.
I recently purchased VCDS to determine if I could “see” the problem. I have a series of measure block groups performed on the same freeway and grade. One particular measure block group is of each of the four injectors. It just seemed odd that the mg values for each injector could be so different at the same moment in time, and I am wondering if this might be the problem or if you had insights for other things for me to check. I put markers when I experienced the hesitation/lurching and it tends to fit with the flat line sections of the chart. Sorry, it appears as though I am not able to post attachments.

 

[Lightflyer1]

Are all services up to date? When you run a diagnostics scan does it show any faults? Post the scan here. Also you posted this in the discussion forum for OBD scanners and would of probably got more attention in the forum dedicated to your model.

 

[dieB4sel]

Approaching a scheduled TB replacement. Everything else is current.

Below is my scan, a looks like the temperature sensor could need to be replaced. When I ran the temperature sensor blocks at freeway, it was in the plateaued at 80 to 85 range.

Thursday,02,May,2013,20:03:11:57853
VCDS Version: Release 11.11.5
Data version: 20121222

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Chassis Type: 3B - VW Passat B5
Scan: 01 02 03 08 15 16 17 19 35 36 37 46 47 55 56 57 58 75 76 77


VIN: WVWCE63B95E132702 Mileage: 223900km/139125miles
-------------------------------------------------------------------------------
Address 01: Engine Labels: 038-906-016-BHW.lbl
Part No SW: 038 997 016 T HW: 028 101 198 2
Component: R4 2,0L EDC G000AG 0314
Revision: 12345678 Serial number: VWZ7Z0E1415409
Coding: 0150034
Shop #: WSC 23303 444 85640
VCID: 2F6DCEF3BDFCB160886
No fault code found.
Readiness: 0 0 0 0 0
-------------------------------------------------------------------------------
Address 02: Auto Trans Labels: 01V-927-156.lbl
Part No: 3B0 927 156 CF
Component: AG5 01V 2.0lPD USA 0505
Coding: 0001104
Shop #: WSC 05311 000 00000
VCID: 6CD719FF4C6A0A78ED4
No fault code found.
-------------------------------------------------------------------------------
Address 03: ABS Brakes Labels: 4B0-614-517.lbl
Part No: 4B0 614 517 G
Component: ABS/ESP front 3428
Coding: 04257
Shop #: WSC 05311
VCID: 25412CDBBF00FB3072A
No fault code found.
-------------------------------------------------------------------------------
Address 15: Airbags Labels: 6Q0-909-605-VW5.lbl
Part No: 1C0 909 605 C
Component: 09 AIRBAG VW61 04 0003
Coding: 12345
Shop #: WSC 05311
VCID: 244731DFB43A0238654
No fault code found.
-------------------------------------------------------------------------------
Address 17: Instruments Labels: 3B0-920-xx5-17.lbl
Part No: 3B0 920 929 C
Component: KOMBI+WEGFAHRSP VDO V07
Coding: 15235
Shop #: WSC 00000
VCID: 275D26D3C50CE920406
WVWCE63B95E132702 VWZ7Z0E1415409
2 Faults Found:
01039 - Coolant Temperature Sensor (G2)
30-10 - Open or Short to Plus - Intermittent
01336 - Data Bus for Comfort System
80-10 - Single-Wire Operation - Intermittent
-------------------------------------------------------------------------------
Address 19: CAN Gateway Labels: 6N0-909-901-19.lbl
Part No: 6N0 909 901
Component: Gateway K<->CAN 0001
Coding: 00006
Shop #: WSC 05311
VCID: F0EF8D8FB0426E9851C
1 Fault Found:
01336 - Data Bus for Comfort System
80-10 - Single-Wire Operation - Intermittent
-------------------------------------------------------------------------------
Address 46: Central Conv. Labels: 1C0-959-799.lbl
Part No: 1C0 959 799 C
Component: 80 Komfortgerát HLO 0004
Coding: 00258
Shop #: WSC 05311
VCID: 377DF69315AC79A0D06
Subsystem 1 - Part No: 1C1959801
Component: 80 Tõrsteuer.FS KLO 0202
Subsystem 2 - Part No: 1C1959802
Component: 80 Tõrsteuer.BF KLO 0202
Subsystem 3 - Part No: 1C0959811
Component: 80 Tõrsteuer.HL KLO 0202
Subsystem 4 - Part No: 1C0959812
Component: 80 Tõrsteuer.HR KLO 0202
1 Fault Found:
01336 - Data Bus for Comfort System
80-10 - Single-Wire Operation - Intermittent
-------------------------------------------------------------------------------
Address 56: Radio Labels: 3B7-035-1xx-56.lbl
Part No: 3B7 035 180 G
Component: Radio PM6 0020
Coding: 00031
Shop #: WSC 05311
VCID: 244731DFB43A0238654
No fault code found.
End ---------------------------------------------------------------------

 

[dieB4sel]

Back again…had to take care of family things first…
Since my last post, I took my TDI to a trusted neighborhood shop. They don’t specialize on TDIs but they are smart and they don’t charge an arm and a leg. At the shop they don’t have VCDS, but they have various systems to monitor engine stats. Here is what they determined or did.
I will restate that I am not anything close to being a “mechanic” but I do try to be involved with engine care. Also, will restate this is a 2005 Passat BHW.
First I showed them my VCDS charts (sorry not able to post charts): Log 013 006 011 showing “injector qty”, engine speed, and manifold intake. The injector qty chart was odd because there was a considerable spread between the injector qtys, typical to see injector #1 at about 1.0, #2 at -0.3, #3 at about 0.0 and #4 around -0.4. (Aware that VCDS cannot diagnose injectors, and these aren’t actual measurements) at the sweet spot on the hesitation (about 50 MPH, up a moderate grade). These differences persist during acceptable performance and during the hesitations. However, all injectors flat line with the above mentioned differences.
Similarly, Log 002 003 006 is also strange. The MAF asks for and receives the appropriate qty during normal operation, but when I push it into the hesitation, there are differences. At the time of the hesitations is asking for about 850, but will actually receive 1200 to 1300.
We looked at VCDS system check log – saw that fault 01039 coolant temperature sensor (G2) fault. No action yet on checking/replacing this sensor.
Repair Shop Actions to Date
· Replicated the reported hesitation on test drive before starting work and after each task below.
· Replaced fuel filter, injector cleaner similar to lubro molly bypass: Problem persists
· Checked timing belt system and determined this was operating to spec
· Replace wire harness to injectors as identified in TSB and IDENTFIX Data Bank recommendation: Problem persists (BTW, they noted that cam shaft wear was minimal)
· Removed intake and cleaned (intakes 2 and 3 were heavily clogged 1 and 4 were clear) : Problem persists
· The shop also mentioned that the EGR asked for 850 mg flow, but received the 1200 to 1300 mg flow during the hesitations. (similar to my MAF values using VCDS)
· Discussed with me the problem that during the hesitation, the ECU is asking for EGR of 850 but actually “appears” to be getting much higher amount. They don’t know why this is so. I have read in the VCDS literature that “if the MAF fails completely, the ECU reverts to an in built guess of air flow. This will log as the EGR actual figure constantly being 470 MG/storke approx”. Also read in the VCDS literature that if the EGR valve is stuck open EGR actual will constantly be lower than specificed and if the EGR valve is stuck closed, the EGR actual will constantly be higher than specified. Neither of these conditions exist.
What Next?
eBahn suggested that
· the ECU be reflashed. Is that just for new car issue? Could it be a problem after 140k miles?
· The MAF be checked. I am assuming that the MAF will either be always failing if the MAF were the problem…so I am thinking this is not the problem?
· Check Timing…done and its okay
Check and adjust the injectors. Haven’t done. Is this possibility?

 

[CopaMundial]

Have you verified that your turbo hoses and vacuum lines are in good health and securely connected?

Also, there is a great tool in the sticky on the ODB board by JollyGreenGiant for plotting graphs of different measuring blocks.
http://forums.tdiclub.com/showthread.php?t=201161
You can then post those images to and image hosting site (photobucket or similar) and use the 'insert image' option to include them in your forum post... thusly:

 

[BobnOH]

Sounds a little like a weak in-tank fuel pump or bad tandem pump.
Also might be good to get a real-time reading on that coolant temp sensor (01039), if it's completely out to lunch, could cause some issues. Read it at ambient temp, then again at operating temp.

 

[dieB4sel]

Problem Solved

Thanks for the responses Copa and BobnOH.

The problem has been resolved (it was indeed the Tandem Pump).

Working with the repair shop folks, they installed an inline gague to monitor the output of the tandem pump. I understand it should have been "rock steady". Instead, the needle was jumping all over the place. It was replaced and the car now works perfectly. The engine is now much smoother across all RPMs than it has been in quite some time.

While we were elbow deep into the engine compartment, we did inspect all the hoses and hose clamps. All the hoses were in excellent shape, two clamps were replaced to ensure solid connection. VCDS results all look great now.