Please help to identify the problem, fluctuating BEW

05 golf BEW tdi sometimes after start the rpms start fluctuating and it almost feels like its running on 3 cylinders and then all of a sudden everything goes to normal and it runs very smoothly. The other time it starts right up and runs perfectly. It is not temperature related as it does it when its warm outside and on the contrary starts right up runs perfectly when its below zero C. But it happens both ways. What happens prior is kind of strange. I almost 100 percent can tell when this is gonna happen because when I cycle glowplugs I see very faint dash lights flickering and when i try to start it sounds like the battery is weak , relay clicking and then when it starts it fluctuates for like a min or two. If theres no lights flicker or relay clicking it starts right up and runs like new. It is obviously electrical problem with some ground maybe or loose connection somewhere, but i just dont know where to start looking. Please chime in if someones is familiar with this.

Sticky ASV?

BobnOH said:

Sticky ASV?

Click to expand...

i was thinking about that too, because it kind of feels like its gonna stall, but why would light flicker and relay click at start?

Sounds like a bad connection somewhere to me.
Clean the battery terminals, fuses over the battery, both battery ground points.

^^what he said^^
Plus check your battery at parts house to be sure it's good, and just go through cleaning grounds.

I lean towards weak battery/connection to block ground stopping it from charging right.

I always start cleaning grounds for electrical issues as the random ones often seen to be ground related.

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after chasing this problem for some time now I still cant figure out whats wrong with it and where exactly the problem is. I have cleaned the grounds under the battery tray, battery terminals, fuses over the battery for several times now. It seem to help in the short run but after a while it happens again. Yesterday attempted to start the car after it was parked inside the garage for 2-3 weeks, it started right up and then started shuttering, fluctuating, and immediately airbag light came on. I shut it off, tried to restart and I noted that the dash lights are flickering and the engine would not turn over , the relay clicked like the battery was dying. Shut it off again, started right up, the airbag light went off too, everything seems to be normal again. Shut it off again, tried to start and the light flickered again, but the engine started but started shuttering, the head lights and the dashboard lights flicker too. Did I miss any more ground somewhere esle? It seems to me like there is not enough of current going to the starter when this happens, and even after it starts and shutters it still kind of feels like the current is cutting off. There is no codes on VCDS. When it works fine I have also noted there is a slight shutter around 1200 rpm, very minor, only at this rpm , it goes away at higher rpm and seems to idle smooth below that, not sure if this is related. The battery is new. Could this be related to CPS? Is there a ground going from the battery to the block?

Sounds like the battery though you said it’s new is now dead. Which would point me to an alternator not charging correctly. Do you have a multimeter? A cheap digital one from Walmart or Home Depot will work. <$30

On a new battery 12.6-8 is what the charge should read with the car not running just sitting in your driveway. 13.8-14.4 is what the battery should read with the car running. A multimeter is indispensable when trying to diagnose electrical problems. If the battery is less than 12.2 fully charge it, I would disconnect it from the car during that process.

If you don’t get around 14 with the car running at the battery. Move the red lead to the bolt on the back of the alternator where the battery cable connects . You should get around 14 there. If not the alternator is bad if you do then the cable between the battery and alternator is loose or damaged.

I chased an issue like this on our old MK3. It ended up being a loose wire.


It sounds an awful lot like an intermittent electrical issue. Which are hard to find.


The main battery ground goes from the battery, to the post under the battery tray, to the engine block/trans bolt under the tandem pump.


I would pull and clean up all of the ground cable circuit. My son's '03 was doing weird stuff until I cleaned all of the electrical connectors by and around the battery. Clean up the battery connections as well.


ETA: I would pull the battery and have it load tested at the same time. That removes a bunch of mystery (a bad cell will do weird stuff and test okay)

mjydrafter said:

I chased an issue like this on our old MK3. It ended up being a loose wire.


It sounds an awful lot like an intermittent electrical issue. Which are hard to find.


The main battery ground goes from the battery, to the post under the battery tray, to the engine block/trans bolt under the tandem pump.


I would pull and clean up all of the ground cable circuit. My son's '03 was doing weird stuff until I cleaned all of the electrical connectors by and around the battery. Clean up the battery connections as well.


ETA: I would pull the battery and have it load tested at the same time. That removes a bunch of mystery (a bad cell will do weird stuff and test okay)

Click to expand...

i would definitely test it or even use another one to rule this out, but I am almost 100 certain this is not the battery as it starts the car even at below 0 with no probs, it is just like you turn the key one time and theres something weird going on with the flickering lights and relay clicking, shutter and airbag light and then you turn the key 20 sec later and it starts right up and runs fine. Is there any " contact enhancing" grease that might help to protect the grounds in this case? I have removed the battery tray for 3 times now with all of the cleaning associated, but I dont think I checked the ground under the tandem pump.

I would wiggle the crank shaft position sensor cable with the engine running to see if anything changes. The fine wires inside the cable become brittle over the years due to the hot environment in which it lies.

Sure sounds like an electrics gremlin. A wire, connector or even inside a relay or switch. Have you checked the circuits to the injectors? Once the car is running it don't need much electrics. I'd also check around the interior fuse/relay block.

A large part seems to be the engine ground. Follow the ground wire to the block and clean it up.
Where the starter is intermittently acting up it's possible that the starter contracts, however, the flickering seems more electrical contact related.
Look at the alternator electrical contacts again. Check voltage when running well and when running poorly.
It never hurts to add a ground to the engine, however it shouldn't be necessary.
One thing I do is check resistance between the ground points and battery negative. Be sure to check ground to alternator housing. I look for .01-.02 Ohms resistance to all grounds.

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bmwM5power said:

i would definitely test it or even use another one to rule this out, but I am almost 100 certain this is not the battery as it starts the car even at below 0 with no probs, it is just like you turn the key one time and theres something weird going on with the flickering lights and relay clicking, shutter and airbag light and then you turn the key 20 sec later and it starts right up and runs fine. Is there any " contact enhancing" grease that might help to protect the grounds in this case? I have removed the battery tray for 3 times now with all of the cleaning associated, but I dont think I checked the ground under the tandem pump.

Click to expand...

There's contact grease which improves contact sold for spark plugs at Auto store. Then there's dielectric which once clean I use to coat the outside of the electrical connections to stop air and water from corroding them in the future.

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here is the video of another occurrence
https://youtu.be/DSIo9mtd4KU


after the engine restarted i actually got the CEL, here is thel og below. All codes later cleared. I actually could not find the ground under the tandem pump, instead there is a ground to the block on the front of the engine below the oil filter accessed from under the car. All cleaned again, seems to be working ok for now, not sure for how long though. Since theres a code related to the ECM could there be some bad connection there? Does the ECM control the starter? Why did the ECM code come up under the auto tran group?





Tuesday,28,April,2020,17:22:54:06633
VCDS -- Windows Based VAG/VAS Emulator Running on Windows 7 x64
VCDS Version: 20.4.0.1 (x64)
Data version: 20200331 DS317.0
www.Ross-Tech.com


VIN: 9BWGR61J954013642 License Plate: 04028-20
Mileage: 194140km-120633mi Repair Order:



--------------------------------------------------------------------------------
--------------------------------------------------------------------------------


Chassis Type: 1J (1J - VW Golf/Bora IV (1998 > 2006))
Scan: 01 02 03 08 15 16 17 19 22 29 35 36 37 39 46 47 55 56 57 75
76

VIN: 9BWGR61J954013642 Mileage: 194140km-120633miles
-------------------------------------------------------------------------------
Address 01: Engine Labels: 038-906-016-BEW.lbl
Part No SW: 038 997 016 L HW: 028 101 181 2
Component: R4 1,9L EDC G000AG 3791
Revision: 12345678 Serial number: VWZ7Z0D0430234
Coding: 0150034
Shop #: WSC 09446 444 84293
VCID: 2757EAC795F4FDBE63-50C8

No fault code found.
Readiness: 0 0 0 0 0

-------------------------------------------------------------------------------
Address 02: Auto Trans Labels: 09A-927-750.lbl
Part No: 09A 927 750 BL
Component: AG5 Getriebe 09A 0262
VCID: 76E9F78352DED43628-50C8

1 Fault Found:
01314 - Engine Control Module
49-10 - No Communications - Intermittent

-------------------------------------------------------------------------------
Address 03: ABS Brakes Labels: 1C0-907-37x-ABS.lbl
Part No: 1C0 907 379 L
Component: ABS FRONT MK60 0101
Coding: 0004097
Shop #: WSC 00000 785 00200
VCID: 336F0E97512C811ECF-50C8

No fault code found.

-------------------------------------------------------------------------------
Address 15: Airbags Labels: 6Q0-909-605-VW5.lbl
Part No: 1C0 909 605 F
Component: 08 AIRBAG VW61 0202 0003
Coding: 12344
Shop #: WSC 00000
VCID: 2757EAC7C5F4FDBE63-508E

1 Fault Found:
00532 - Supply Voltage B+
07-10 - Signal too Low - Intermittent

-------------------------------------------------------------------------------
Address 17: Instruments Labels: 1J0-920-xx5-17.lbl
Part No: 1J0 920 907 F
Component: KOMBI+WEGFAHRSP VDO V03
Coding: 15234
Shop #: WSC 55113
VCID: 2C5D15EBDC12DEE68E-508E
9BWGR61J954013642 VWZ7Z0D0430234

No fault code found.

-------------------------------------------------------------------------------
Address 19: CAN Gateway Labels: 6N0-909-901-19.lbl
Part No: 6N0 909 901
Component: Gateway K<->CAN 0001
Coding: 00006
Shop #: WSC 00000
VCID: 70E5C19B30BAFA06F2-508E

No fault code found.

-------------------------------------------------------------------------------
Address 46: Central Conv. Labels: 1C0-959-799.lbl
Part No: 1C0 959 799 C
Component: 8C Komfortgerát HLO 0004
Coding: 00258
Shop #: WSC 04926
VCID: 37773A8715546D3EF3-4A82

Subsystem 1 - Part No: 1C1959801A
Component: 8C Tõrsteuer.FS KLO 0202

Subsystem 2 - Part No: 1C1959802A
Component: 8C Tõrsteuer.BF KLO 0202

Subsystem 3 - Part No: 1C0959811A
Component: 8C Tõrsteuer.HL KLO 0202

Subsystem 4 - Part No: 1C0959812A
Component: 8C Tõrsteuer.HR KLO 0202

10 Faults Found:
00928 - Locking Module for Central Locking; Front Driver Side (F220)
54-10 - Incorrectly Equipped - Intermittent
00929 - Locking Module for Central Locking; Front Passenger Side (F221)
54-10 - Incorrectly Equipped - Intermittent
00930 - Locking Module for Central Locking; Rear Left (F222)
54-10 - Incorrectly Equipped - Intermittent
00931 - Locking Module for Central Locking; Rear Right (F223)
54-10 - Incorrectly Equipped - Intermittent
00932 - Electric Window Motor; Drivers Side (V147)
62-10 - No or Incorrect Adjustment - Intermittent
01331 - Door Control Module; Driver Side (J386)
37-00 - Faulty
01359 - Internal Central Locking Switch; Passenger Side (E198)
27-10 - Implausible Signal - Intermittent
00934 - Electric Window Motor; Rear Left (V26)
62-10 - No or Incorrect Adjustment - Intermittent
01333 - Door Control Module; Rear Left (J388)
37-00 - Faulty
01334 - Door Control Module; Rear Right (J389)
37-00 - Faulty

-------------------------------------------------------------------------------
Address 56: Radio Labels: 3B7-035-1xx-56.lbl
Part No: 3B7 035 180 G
Component: Radio ZSW 0016
Coding: 00031
Shop #: WSC 00000
VCID: 244DFDCBB4C216A646-50AC

No fault code found.

End-------------------------(Elapsed Time: 05:03)--------------------------

That's a lot of codes!

01314 - Engine Control Module

49-10 - No Communications - Intermittent

This one caused me to get a new ecu, it was the only fix. I had to send my old ecu to Malone with the new to get it flashed with the old info and have the immobilizer deleted..
First you want to check the wiring and be sure the issue isn't the plug or faulty ground to the ecu. Also it might be advantageous to replace the 109 relay to be sure it's not causing the power to cut in and out.

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eddieleephd said:

That's a lot of codes!

01314 - Engine Control Module

49-10 - No Communications - Intermittent

This one caused me to get a new ecu, it was the only fix. I had to send my old ecu to Malone with the new to get it flashed with the old info and have the immobilizer deleted..
First you want to check the wiring and be sure the issue isn't the plug or faulty ground to the ecu. Also it might be advantageous to replace the 109 relay to be sure it's not causing the power to cut in and out.

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Click to expand...

yeah, but my guess is all of these codes come up because of the intermittent power cut out to everything/ low voltage, all cleared out later, everything is kind of going dim when this shutter happening. Where is the ECM located on the BEW tdi, is it still under the rain tray? also since this come up under the transmission address is it the transmission control module or the main ECM?

Yeah, I would believe the ecu and tcu are under the cowl beings it's an MKIV. Not sure exactly.
If it were me I would pull the cowl and clean the grounds, pull the plugs and inspect the wires. Clean plugs with electrical cleaner, put electrical contact grease on the pins with a little brush and see if that resolves the issues.

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