Cuts out while driving

Hi and thanks for using 2CarPros.

Is the check engine light staying on while the engine is on? If so, you need to scan the computer to determine what diagnostic trouble code is stored.

https://youtu.be/YV3TRZwer8k

Next, if the light isn't staying on, let me know if the engine starts right up after it stalls. Here is a link that discusses engine stall while driving. Take a look through it.

https://www.2carpros.com/articles/engine-stalls

Restarting the engine right after turning it off should not have caused this problem. Also, can you confirm if this is truly a 1.9L engine?

Thanks,

Joe

Hi Joe,

It is a 1.9 tdi. The engine light doesn't stay on when the engine is going.

The engine doesn't start straightaway after stalling. It can take ten minutes plus of turning the key before it fires.

What would be your best guess is the source of the problem?

Thanks,
Matt

Welcome back:

Honestly, if you have to cycle the key to get it to restart, my first suspect is fuel pressure. Have you changed the filter recently? It may be partially plugged.

Interestingly, I am only showing a 2.0L turbo diesel. Anyway, I am going to provide the directions specific to checking fuel pressure for the 2.0. It should be similar in design. The attached pictures correlate with these directions.

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COMPONENT TESTS AND GENERAL DIAGNOSTICS
Tandem Pump, Checking

Special tools, testers and auxiliary items required



picture 1


- Pressure gauge VAS 5187



picture 2


- Torque wrench (5 to 50 Nm) V.A.G 1331
- Vehicle diagnostic, testing, and information system VAS 5051
- Diagnostic cable VAS 5051/6A

Conditions
- Coolant temperature must be at least 85 degrees C.
- Pump-Injector units O.K.
- Fuel filter and fuel lines must not be plugged.
- Fuel level sensor must be OK.

Work sequence
- Loosen charge air tube and set aside.



picture 3


- Remove locking bolt - arrow -.



picture 4


- Install pressure gauge VAS 5187 as shown.
- Secure charge air tube in place again.
- Start engine and run at idle speed.
- Connect vehicle diagnostic, testing, and information system VAS 5051 and select operating mode "Vehicle self-diagnosis".
- Press button "01 - Engine electronics" on display.
- Press diagnostic function"08 - Read measured value block".
- Using number keypad, enter display group "1" and acknowledge entry with Q-key.
- Read idle RPM in display field "1".
- Increase engine speed to 4000 RPM.
- Observe displayed pressure on pressure gauge.
Specification: min. 7.5 bar
- Return engine to idle speed.

If the specification is not obtained:
- Clamp return line closed between fuel filter and tandem pump with a hose clamp.
- Increase engine speed to 4000 RPM.
- Observe displayed pressure on pressure gauge.
Specification: min. 7.5 bar
- Return engine to idle speed.

If the specification is now obtained:
- Pressure loss at Pump-Injector unit.
- Replace O-rings of Pump-Injector unit.

If the specification is not obtained:
- Replace tandem pump Tandem pump, removing and installing.

NOTE: After removing the pressure gauge, fasten the locking bolt to 25 Nm. Always replace the seal.

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This is where I would start. Make sure the fuel filter is clean.

Let me know what you find or if this helps.

Take care,
Joe

Hi Joe,

Thanks very much for that. A high pressure fuel pump has been fitted along with relays etc. I think at this stage we can rule out that end of things.

It only stops very intermittently, like once every two to three months. Do you have any other thoughts on what might be causing it? Would it be something electrical?

Thanks,

Matt

Hi Matt:

That's a tough one since it is so irregular. Since it is rare, I suspect it would most likely be something electrical. However, it's going to be difficult to check other than if the check engine light comes on which would indicate a trouble code. That would point you into the right direction.

Considering that, I hate to say it, but you will most likely have to wait until it gets bad enough to identify the cause. I wish I had an easy answer, but how can we check it?

Let me know if it gets worse. If it does, I would check to see if you are getting spark and fuel. I realize fuel shouldn't be an issue, but it still could be a problem.

Take care,
Joe

Hi Joe,

Yeah it is frustrating.It's never stalled when in the garage so no faults have ever showed up on the computer.

Well listen, thanks a million for all your help. The articles you sent on were particularly helpful. Very helpful service you provide.

All the best,

Matthew

Matthew:

You are very welcome. I just wish I could give you a more definitive answer. Regardless, if it gets worse or you ever have other questions, feel free to come back anytime.

Take care,
Joe