VW Bora ARL - Runs and jerks severely under load

Hello everyone,

I have a somewhat minor problem with my VW Bora.

Vehicle Data:

- VW Bora, Year 2003
- MKB: Workplace Safety
- 6-speed manual transmission
- Approximately 135,000 km driven
- Completely original, without any modifications like chiptuning, etc.

Symptoms:

- It stutters and produces a very strong misfire when loaded beyond approximately 30%. In the low-speed range (and with little load), it runs relatively normally. It starts and stops well both when cold and when warm. The space is completely silent.

What has been done so far:

- PD cable replaced
- LMM replaced
- PD components replaced
- Engine control unit replaced
- Measured the lines to the MSG
- AGR is under control
- VTG is in control
- Diesel temperature sensor replaced
- Suction tube (on the suction tube) load sensor controlled

Phenomena:

After I had changed the LMM, it initially performed just as modestly as the previous one. The next day, I took a short drive again, and during that time, the error suddenly disappeared. It ran perfectly normally and accelerated as usual up to almost 240 km/h. Then, that evening, the same thing happened, but in reverse. It was running smoothly, but then it started to jerk again while I was driving.

I have now ventured into LOG trips. One is at idle and two are under full load. They aren't very long, as the car is shaking violently and a black cloud of smoke is trailing behind it.

I kindly ask for your understanding if the log entries are not perfectly accurate. These were my first attempts.

Thank you very much.

Best regards
Timm

Was is the length of the intake manifold?

So far, the air intake path has only been visually inspected.

To extract it, I would first need to build something.

Then I would do this: get some drain pipe plugs that fit, make a hole, inflate the tire valve, insert it into the hose, attach the fitting, and carefully pump it up.

Alternatively, also check the small vacuum hoses, I've already had several instances where they had a crack in one spot that I couldn't see until I had to remove them.

Hello,

"The Log shows good smoke limits, but if the car still has no power and accelerates, it probably means that air is being lost, as Rüdis notes."

In the first log, the driver's desired moment value goes to 0 at some point. Since I suspect that you didn't suddenly release the gas pedal, it's either because the signal from the gas pedal (check the wiring harness and pedal sensor) was too strong, or because the engine control unit (ECU) performed a reset, or because the high values from the mass airflow sensor (MAF) were causing this behavior.
But I don't know if after a reset (specifically, with the "Relais 109" for the search function), the diagnostic connection wouldn't need longer to re-establish.

Post a car scan.

Best regards, Rainer

@ Rüdi:

I will make a fitting connector with a pressure connection for the air intake hose tomorrow. According to Elsa Win, 0.5 bar should be sufficient to detect a hissing or leak.

Can I possibly test the vacuum hoses with a vacuum pump?

What still surprises me is: why was it suddenly located about 40km away? A crack or damage doesn't repair itself automatically.

@ dieselschrauber:

Interesting, so the soot reduction has nothing to do with the exhaust gases in that sense? Because I had already produced a very clear and black soot cloud. I hope that I will be able to get the air intake system checked/replaced by the end of the week.

Regarding the "driver's desire" aspect; No, my foot was always 100% on the accelerator pedal, except during gear changes. However, I definitely felt the jerking. But there was no warning light or anything similar. As if the car suddenly ran out of fuel.

I only had one scan before my trip. However, it was identical to the one I had after my trip. Therefore, I decided to discard it. Is that sufficient? Otherwise, I will do another quick scan tomorrow afternoon.

Thank you and best regards, Timm

Hello Timm,

Unfortunately, the car scan didn't work out. Please add or copy the text here.

The Russian border is already working, it just needs to be completely sealed. The boost pressure in your engine is approximately 1.5 bar, and this is a reasonable range to test within.
But please, make sure the caps don't fly around.

Best regards, Rainer

Good evening, Rainer,

Sorry, then now in text form:

-------------------------------------------------------------------------------
Address 01: Engine Electronics Label File: DRV\038-906-019-ARL.lbl
Part Number: 038 906 019 KG
Part Number: 1.9L R4 EDC G000SG 4900
Encoding: 00002
Operating number: WSC 01266
VCID: 66944C29117587D753A-4B3C

No error codes found.
Readiness: 0 0 0 0 0
-------------------------------------------------------------------------------
Address 03: Brake Electronics Label File: DRV\1C0-907-37x-ESP-F.lbl
Part Number: 1C0 907 379 M
Part: ESP FRONT MK60 0102
Encoding: 0019970
Operating number: WSC 01266 785 00200
VCID: 3430E661122925471DE-5184
No error codes found.
-------------------------------------------------------------------------------
Address 08: Climate/Heating System. Label file: DRV\3Bx-907-044.lbl
Part Number: 3B1 907 044 C
Component: CLIMATRONIC C 2.0.0
Encoding: 11000
Operating number: WSC 01266
VCID: 211E1F35B8DBA0EFE68-51F2
No error codes found.
-------------------------------------------------------------------------------VCDS
Self-diagnosis log
Saturday, February 29, 2020, 11:15:15:09390
Page 2
Vehicle Identification Number: Vehicle License Plate:
Address 15: Airbag Label file: DRV\6Q0-909-605-VW5.lbl
Part Number: 1C0 909 605 F
Part: 02 AIRBAG VW61 0101 0003
Encoding: 12338
Operating number: WSC 01266
VCID: 270A012DD6FF5EDFA8C-5160
1 Error found:
00532 - Supply Voltage
07-10 - Signal too weak - Sporadic
-------------------------------------------------------------------------------
Address 17: Relay Cabinet Label File: DRV\1J0-920-xx5-17.lbl
Part Number: 1J5 920 846 C
Part: KOMBI+WEGFAHRSP VDO V20
Encoding: 21114
Operating Number: WSC 00000
VCID: 3038EA71E3311967796-5160

1 Error found:
01330 - Central Control Unit for Comfort System (J393)
49-10 - No communication - Sporadic
-------------------------------------------------------------------------------
Address 19: Diagnosis Interface Label File: DRV\6N0-909-901-19.lbl
Part Number: 6N0 909 901
Component: Gateway K<->CAN 0001
Encoding: 00006
Operating number: WSC 01266
VCID: 70B82A7123B15967396-5160
1 Error found:
01330 - Central Control Unit for Comfort System (J393)
49-10 - No communication - Sporadic
-------------------------------------------------------------------------------VCDS
Self-diagnosis log
Saturday, February 29, 2020, 11:15:15:09390
Page 3
Vehicle Identification Number: Vehicle License Plate:
Address 46: Comfort System Label File: DRV\1C0-959-799.lbl
Part Number: 1C0 959 799 B
Part Number: 18 Comfort Gear HLO 0003
Encoding: 00259
Operating number: WSC 01266
VCID: 3634DC690155375723A-4B3C
Subsystem 1 - Part Number: 1C1959801A
Part Number: 18 Tõrsteuer.FS KLO 0202
Subsystem 2 - Part Number: 1C1959802A
Part Number: 18 Tõrsteuer.BF KLO 0202
Subsystem 3 - Part Number: 1C0959811A
Part Number: 18 Tõrsteuer.HL KLO 0202
Subsystem 4 - Part Number: 1C0959812A
Part Number: 18 Tõrsteuer.HR KLO 0202
No error codes found.
Ende--------(Duration: 04:59, Battery Voltage Start/End: 14.6V/14.6V)---------



I have made the stopcock today. I will also equip it with an additional clamp and a "fang protection" device. I also have the leak detection spray ready. I just hope that the whistling can be heard clearly.

Best regards, Timm

Good morning everyone,

I apologize for the double post.

Yesterday, I finally had the time to bleed the cooling system. Together with a leak detection spray, I went on the search. I could already hear it clearly at 0.5 bar. However, the hissing was not coming from a hose or a coupling, but from the oil dipstick. I suspect that the air was trying to find its way up through the valve cover.

Everything else was completely blocked. Now I am standing at the beginning of the mystery again.

I will now, as a precaution, replace relay 109, but I don't actually believe it's the cause.

The shaking and jerking is still present.

Best regards, Timm

Hello,

In my opinion, you made a wrong turn.

First, there should be no hissing from the oil dipstick, because when the air intake system is properly disconnected, there should be no connection to the engine. But it all depends on what one wants to check, and you don't write anything about that, presumably because you don't know yourself.

Secondly, it is questionable (depending on the engine's position), whether significant pressure can actually be built up when the engine is disconnected.

What was the pressure in your intake manifold, and how long did it last? Seconds until nothing? Exactly. Nothing to consider.

I would like to emphasize this once again:
/newuser.php

Try to understand when there is not enough air for combustion, and therefore soot is formed. Then you can also carry out meaningful debugging.

Best regards, Rainer

Quote:

In the first log, there's a moment where the driver's desired setting reaches 0. Since I suspect that you didn't suddenly release the gas pedal, the gas pedal signal (check the wiring harness and the pedal sensor)

I once had a similar situation where, despite pressing the accelerator pedal to the floor, the value from the pedal was still zero. The cause was then a not a BOSCH LMM.

I think that the STG simply experienced a loss of "juice" (voltage drop) at certain points, without any errors being recorded.

I would also like to check the wiring harness in the engine compartment.

In the event of a fault in the pedal position sensor or its wiring, it should immediately enter a failsafe mode.

I think that the area around the turbocharger doesn't need to be searched. It will be an electrical problem.

During the leak test, you should not expect any pressure to be held. Some air will always escape through open valves into the cylinders, through the crankshaft case ventilation (unless it is closed), and through the EGR. The manufacturer also explicitly points this out. Therefore, the hissing sound coming from the oil well.
hg
Herbert

Herbert wrote:

When performing a leak-down test, you should not expect any pressure to be held. Some air will always escape through open valves into the cylinders, through the crankshaft case ventilation (unless it is closed), and through the EGR valve. The manufacturer also explicitly points this out. Therefore, the hissing sound coming from the oil well. hg Herbert

Therefore, I also used 2 plugs to properly inflate the intake manifold.

I'd also like to add my comments.

First of all, thank you all for your responses.

Quote:

In my opinion, you made a wrong turn.

Exact according to the VW repair manual. The stop is a replica of the original VAG tool, and the rest I built from standard industrial supplies.

I maintained the pressure in 3 stages:

- 0.5 bar (VW specification according to the manual)

- 0.8 bar

- 1.3 bar (I didn't want to spend more.) More details below.

The pressure lasted for several seconds and subsided very slowly. There were only noticeable acoustic noises coming from the oil level indicator. All other connections were treated with a leak detection spray and held absolutely tight. On the last air intake hose (shortly before the AGR), you could also feel the pressure clearly. Therefore, I left it at 1.3 bar.

Quote:

Seconds until nothing? Exactly. Nothing to consider.

I'll just pause for a moment and think about things while I'm working. Just because I'm not a TDI professional doesn't mean I don't work conscientiously. I also installed and tested the turbocharger system on my Nissan Skyline myself. "That's where we're talking about a whole other level of boost..."

But let's get back to the main topic;

I have - as suggested - thoroughly reviewed the topics again.
I would exclude the LMM. Both the original and the new Bosch (even the one with an identical Bosch TN) differ very little from each other. With the new one, it's only slightly better in terms of the data read out.

I have now also purchased a vacuum pump and will take a closer look at the connections for creating a vacuum. I will also check the diesel pressure at the tandem pump.

The magnetic valves delivered what they should have in the actuator diagnosis. The "VTG Gymnastik" (presumably a specific exercise or procedure) also ran without problems. The charger is immediately responsive.

Furthermore, I examined the sensors to see if there were any sudden jumps in the graph (For example, with the dual temperature sensor or also with the accelerator pedal). Everything seems to be in order here as well.

The air cooler is absolutely clean, and the air filter mat also looks perfectly okay.

Only the AGR value is above the TARGET (See Image // I apologize for the lighting conditions). The value was very consistent and did not show any outliers. The solenoid valve was set to 4.8% instead of "Target Value (Idle): 40.0...80.0 %".

I look forward to your kind feedback and advice.

Best regards, Timm.

Hello,

Your AGR value at idle means that it is stuck and cannot open.
Your ARL engine should have an EGR system controlled by vacuum. I would check the vacuum system for leaks and make sure that all vacuum lines are correctly connected.

Best regards, Rainer

Good evening everyone,

I was a bit more active today.

Quote:

Your ARL engine should have an under-pressure-controlled AGR (Exhaust Gas Recirculation), I would check the vacuum system for leaks and ensure that all vacuum hoses are correctly connected.

Okay, that's correct. The AGR valve is controlled by vacuum.

I have successfully tested all the hoses. All the hoses were able to maintain the self-generated vacuum of -0.8 bar (for approximately 40-60 seconds, after which I stopped). The auxiliary pump also delivered -0.8 bar in idle. At 1500 RPM, I unfortunately couldn't check, as I was alone and the gauge doesn't have a tachometer.

To see how well the suction valve was working, I disconnected the hose again and found that there was oil and dirt present. Is this normal, or is this too much? (The vehicle currently has 135,000 km on it). Also, the hose is also attached to the collar/coupling, but not always perfectly.

For me, it seems like the hydrostatic bearing in the turbo is defective. However, it's questionable whether this has such an impact that the car is emitting so much smoke. I wouldn't have suspected the crankshaft ventilation directly.

Please find a few photos related to the above. Found.

Next, I would check the diesel pressure. I am still waiting for the arrival of the appropriate tool.

Thank you in advance.

Best regards, Timm