A3 8L 1.9tdi ALH engine cutting out

[toomanybuttons]

Hi guys, The car has been losing power for some time now, the tachometer fluctuates occasionally (at a constant speed of 50 km/h, it oscillates by 100–200 rpm, stabilizes, and then after 10 seconds it happens again, and so on) and the car stops while driving (right before stopping, the red oil warning light appears, and the engine dies. After that, it won’t start until I disconnect the battery terminal).

I should mention that someone tampered with all the vacuum hoses! Since then, it has no power. I’ve looked for diagrams but cannot find the exact ones for this model. I also have two hoses under the exhaust manifold, and I swapped them around so much that I’m at my wit’s end.

I’ve replaced: the fuel filter, cleaned the EGR and intake manifold, replaced the glow plugs, cleaned the ECU connectors, and the oil pressure sensor.

I’m attaching the VCDS scan:

Audi A3 8L 1.9 TDI ALH 1998 230000km

Chassis Type: 8L - Audi A3/S3 (1997 > 2005)
Scan: 01 02 03 08 15 16 17 22 35 37 45 55 56 57 75 76
Mileage: 231110km-143605miles
-------------------------------------------------------------------------------
Address 01: Engine Labels: 038-906-018-AGR.lbl
Part No: 038 906 018 BB
Component: 1,9l R4 EDC 00AG 1818
Coding: 00001
Shop #: WSC 63142
VCID: 57EB8B41861E9A621E1-4B1E
2 Faults Found:
00575 - Intake Manifold Pressure
17-00 - Control Difference
00550 - Start of Injection Regulation
17-00 - Control Difference
Readiness: N/A
-------------------------------------------------------------------------------
Address 02: Auto Trans Labels: 01M-927-733.lbl
Part No: 01M 927 733 ES
Component: AG4 Getriebe 01M 3712
Coding: 00000
Shop #: WSC 00000
VCID: 055791092C32D8F23CD-0962
6 Faults Found:
00518 - Throttle Position Sensor (G69)
16-10 - Signal Outside Specifications - Intermittent
00660 - Kickdown Switch or Throttle Position Sensor
27-10 - Implausible Signal - Intermittent
00529 - Engine Speed Signal Missing
35-10 - - - Intermittent
00545 - Engine-Transmission Electrical Connection
31-10 - Open or Short to Ground - Intermittent
01314 - Engine Control Module
49-10 - No Communications - Intermittent
01312 - Powertrain Data Bus
49-10 - No Communications - Intermittent
-------------------------------------------------------------------------------

 

[MPH]

Here are a couple of files to look over in the meantime about the injection glow plug system and engine mechanics @MPH

 

[thegoal007]

have you cleared all the faults after doing all that work and re-run and re-test?
If so, you have quite a few reported issues there. I would read up on each code to see if there is a possible common issue linking all or some of them.

 

[toomanybuttons]

Here are a couple of files to look over in the meantime about the injection glow plug system and engine mechanics @MPH

Hi, I've tried to read this diagram and use it to set the hoses right:

In picture one, you can see that I have no vacuum reservoir, and I think my N18 is in the middle and N239 is on the left.

In picture 2, is this one-way valve?

In picture 3, I have 2 hoses coming from down there; I assume they are from the turbocharger. In every diagram I've searched on the internet, I couldn't find 2 hoses like mine.

 

[toomanybuttons]

have you cleared all the faults after doing all that work and re-run and re-test?
If so, you have quite a few reported issues there. I would read up on each code to see if there is a possible common issue linking all or some of them.

Hi, I did it already and cleaned all the faults, but after a while the issue persists, the car has no power and stops from time to time.

I assume, the most important is 00575 -

Intake Manifold Pressure: Control Limit Not Reached​

Possible Symptoms​

• Sudden complete loss of Power
• Reduced Power

Possible Causes​

• Hoses incorrect connected, disconnected, blocked or leaking
• Pressure Unit for Turbo Charger defective
• Solenoid Valve for Boost Pressure Control (N75) defective

(see the above post; I'm trying to fix the damn hoses but there are too many and no diagram can't help me.)

 

[MPH]

https://webautocats.com/en-gb/etka/audi/a3/201/121400/

A3/S3/Sportb./Lim./qu. (1997 - 2000) - Vacuum system. exhaust gas recirculation. > ETKA Online > WebAutoCats.com

Audi parts catalog. Vacuum system. exhaust gas recirculation.. Spare parts catalog ETKA Online.

webautocats.com

A3/S3/Sportb./Lim./qu. (1997 - 2000) - Exhaust gas turbocharger. exhaust manifolds. > ETKA Online > WebAutoCats.com

Audi parts catalog. Exhaust gas turbocharger. exhaust manifolds.. Spare parts catalog ETKA Online.

webautocats.com

Maybe these diagrams can be of assistance.