Hello,

 

So I'm having a really annoying fault that I can't get the bottom of. Sometimes when I accelerate it feels that the PD170 vRS isn't producing the full power it has. I seen a few others have this fault too. Then sometimes its perfect and will throw you back into the seat.

 

I've got no codes or lights coming up. Checked injectors which all seem to be good as new, the turbo was cleaned and checked (Waste gate, actuator etc which according to my mechanic was ok), no codes for MAF etc.

 

I seen someone else on here had something similar but the preglow warning light would flash and it turned out to be a sticky actuator. I did have this light a few times a number of years ago but hasn't shown since and never really looked into why it was coming up.

 

The fuel filter was a wee bit dirty but is serviced every 5k miles (bad diesel). So I changed this and still have this intermittent fault. I don't know what to check next as the car is going perfect other than this and is achieving 54mpg and not smokey. It still has the dpf but it definitely isn't regens causing it. Anybody any ideas? I have VCDS.

 

Thanks

Jack

Try running a data log of requested turbo boost vs actual.

 

If you can capture the event and it shows underboost then I'd say a thorough investigation of the vacuum system and electronics together with turbo actuator and VNT movement should find your problem.

12 hours ago, MicMac said:

Try running a data log of requested turbo boost vs actual.

 

If you can capture the event and it shows underboost then I'd say a thorough investigation of the vacuum system and electronics together with turbo actuator and VNT movement should find your problem.

Hello,

 

Thanks for the reply. Is this hard to do or whats the best way of going about it?

 

Thanks

Jack

I have no experience with VCDS.

 

Running Delphi on a laptop I can select various parameters to monitor and record in real time AKA Flight Recorder Mode to analyse later.

 

Typically for the aforementioned parameters it would be viewed as a graph plot over time, including the accelerator pedal position in the recording might also be beneficial.

2 hours ago, MicMac said:

I have no experience with VCDS.

 

Running Delphi on a laptop I can select various parameters to monitor and record in real time AKA Flight Recorder Mode to analyse later.

 

Typically for the aforementioned parameters it would be viewed as a graph plot over time, including the accelerator pedal position in the recording might also be beneficial.

Just looked up there you can log stuff on vcds so I'll give it a go!

18 hours ago, MicMac said:

Try running a data log of requested turbo boost vs actual.

 

If you can capture the event and it shows underboost then I'd say a thorough investigation of the vacuum system and electronics together with turbo actuator and VNT movement should find your problem.

Tried there cant get vcds to stay communicated lol. Is there anything you'd suspect of being wrong or faulty?

Vacuum solenoid/wiring fault.

 

Vacuum hose damaged.

 

VNT mechanism sticking.

 

From your initial post you may have a faulting turbo actuator.

 

Given its sporadic nature it's impossible to say for sure via an online forum which is why a data log of the event would help.

 

Maybe a fuel additive and Italian tune-up is all it needs.

 

 

17 minutes ago, MicMac said:

Vacuum solenoid/wiring fault.

 

Vacuum hose damaged.

 

VNT mechanism sticking.

 

From your initial post you may have a faulting turbo actuator.

 

Given its sporadic nature it's impossible to say for sure via an online forum which is why a data log of the event would help.

 

Maybe a fuel additive and Italian tune-up is all it needs.

 

 

I understand. I did the Italian tune up and have run millers oil through regularly so I'd say its something you've mentioned above. I have my vcds on a VM which is probably causing the fault when logging. All signs seem to be actuator. Just very rare that there no codes. Mechanic said that vanes were perfect so hoping I can get the fault!

 

There usually a code associated with boost on sticky vanes? Could be anything tbh car is at 150kmiles. There's also not smoke and mpg isn't affected. No hissing sounds either.

Edited 11 September, 20214 yr by JacksVRS

Variable vacuum controls the actuator position between max boost at low RPM and lower boost at high RPM with a spring returning the actuator to the failsafe low boost position (at rest).

 

If it is an actuator related issue then it can only be:

 

1. Failure of the tandem pump to produce consistent vacuum/hose deterioration, although a firm brake pedal with loss of servo assist/poor braking may well also be evident.

 

2. Vacuum delivery to the actuator via the solenoid valve, again leaky hose(s) or solenoid/wiring (I think the 2.0 also has an electronic boost position sensor, I've only worked on the 1.9PD).

 

3. A sticky VNT mechanism, possibly physical wear not just particulate build-up.

10 minutes ago, MicMac said:

Variable vacuum controls the actuator position between max boost at low RPM and lower boost at high RPM with a spring returning the actuator to the failsafe low boost position (at rest).

 

If it is an actuator related issue then it can only be:

 

1. Failure of the tandem pump to produce consistent vacuum/hose deterioration, although a firm brake pedal with loss of servo assist/poor braking may well also be evident.

 

2. Vacuum delivery to the actuator via the solenoid valve, again leaky hose(s) or solenoid/wiring (I think the 2.0 also has an electronic boost position sensor, I've only worked on the 1.9PD).

 

3. A sticky VNT mechanism, possibly physical wear not just particulate build-up.

Thanks for all the advice. Im going to mention all this to my mechanic. There just so much it could be. I took the car a spin there and noticed it straight away took ages to climb to 3k revs in 3rd. On the same run 5 mins later I again give her a bit of throttle and behold it was perfect reaching the 3k in the blink of an eye.

21 hours ago, MicMac said:

Variable vacuum controls the actuator position between max boost at low RPM and lower boost at high RPM with a spring returning the actuator to the failsafe low boost position (at rest).

 

If it is an actuator related issue then it can only be:

 

1. Failure of the tandem pump to produce consistent vacuum/hose deterioration, although a firm brake pedal with loss of servo assist/poor braking may well also be evident.

 

2. Vacuum delivery to the actuator via the solenoid valve, again leaky hose(s) or solenoid/wiring (I think the 2.0 also has an electronic boost position sensor, I've only worked on the 1.9PD).

 

3. A sticky VNT mechanism, possibly physical wear not just particulate build-up.

Could a bad throttle body cause any of the symptoms im having?

Doubtful, diesels don't have throttle bodies.

34 minutes ago, MicMac said:

Doubtful, diesels don't have throttle bodies.

Ah I see. Im learning haha. Whats the hose or is suppose to be loose with this wetting around it?

35 minutes ago, MicMac said:

Doubtful, diesels don't have throttle bodies.

Ah I see. Im learning haha. Whats the hose or is suppose to be loose with this wetting around it?