Evening all.

I had a head gasket fail so have changed it, head skim etc etc. At the same time I changed the core of the turbo as it had an internal oil leak.

All went well and the xar starts and ticks over as expected.

When driving, after it warms up there is an intermittent violent shaking and loss of power. Foot off the accelerator stops it but it comes back again when the engine is under load. It happens anywhere between 1500 a d 2500 revs. If I pull over the tick over is OK.

There are no fault codes for anything on the car in relation to the issue.

I'm assuming it's a fueling problem.

From what I've read online it could be 1 of several issues, but the violent shaking others experience seems only to be on tick over. I'm assuming it's an injector or the head loom but it has the potential to be a money pit buying parts to replace as guesswork on a car with 260k + miles.

 

Any ideas of what it could be.

What did you scan it with? I'd expect to see at least a saved code for an intermittent  misfire. 

 

I'm not great on engine codes, is BKD one of the 2.0 16V diesels with the PD injection on?

 

 

Camshaft timing, check the torsion value if it is a measurable parameter in VCDS, mine was on the PD engine but not on my current car with a Common Rail TDi.

 

If the torsion value can be checked and it is zero then make sure it is not a false zero through being outside of measurable limits, it should vary when the engine is revved.

Check the resistance of the injectors, plenty of advice on how to on here.

 

I suspect it's a loose crimp on one or more of the connectors, at certain temperatures/RPM it will give the symptoms you described, however from experience it has to become as violent as a bucking bronco before a misfire code is stored and no EML will display.

4 hours ago, StevesTruck said:

What did you scan it with? I'd expect to see at least a saved code for an intermittent  misfire. 

 

I'm not great on engine codes, is BKD one of the 2.0 16V diesels with the PD injection on?

 

 

Yes it's the 2.0 16v pd.

4 hours ago, J.R. said:

Camshaft timing, check the torsion value if it is a measurable parameter in VCDS, mine was on the PD engine but not on my current car with a Common Rail TDi.

 

If the torsion value can be checked and it is zero then make sure it is not a false zero through being outside of measurable limits, it should vary when the engine is revved.

Just need to get vcds!

1 hour ago, MicMac said:

Check the resistance of the injectors, plenty of advice on how to on here.

 

I suspect it's a loose crimp on one or more of the connectors, at certain temperatures/RPM it will give the symptoms you described, however from experience it has to become as violent as a bucking bronco before a misfire code is stored and no EML will display.

I've been told to drive hard with the problem to try and get a fault code, but so far no joy and mild whiplash 

4 minutes ago, etskoda said:

Yes it's the 2.0 16v pd.

Scanned with a bluetooth OBD2. It shows a couple of codes but they are related to a non coded radio.

The whiplash won't do the engine/transmission any favours either but I know what you mean.

 

For the 10 minutes it takes to unscrew the injector harness and measure the resistances I'd suggest that to hammering the nails in the old girl's coffin.

I had exactly this problem on my Jetta with the bkd engine, thankfully whilst I was still paying for the extended warranty. I believe it was fuel starvation from the tandem pump which was replaced. When I get home I’ll try and find the invoice and reply. 
 

It caused a nasty back and forth sensation which sounds like your whiplash explanation to me. Out of interest when was the fuel filter last changed, and if you did it yourself, was it black? 

 Changed the fuel filter when I did the head gasket. Yes the old one was black.

On 16/02/2022 at 00:30, MicMac said:

The whiplash won't do the engine/transmission any favours either but I know what you mean.

 

For the 10 minutes it takes to unscrew the injector harness and measure the resistances I'd suggest that to hammering the nails in the old girl's coffin.

I'll do this at the weekend.

I'll check the whole loom, give it a clean and check that the plugs are actually tight on the injectors.

Whilst I'm in there I'll check the timing and the injector rockers.

 

If that doesn't sort it I'll order piece of glass and make a coffee table out of it.

21 hours ago, etskoda said:

 Changed the fuel filter when I did the head gasket. Yes the old one was black.

If the old one was black I’d take a look at the tandem pump. Mine was black due to oil contamination. 

The filter will naturally become black from trace amounts of oil contamination in a PD engine, I wouldn't be concerned if weekly checks are good.

Did the injector harness check today.

All the brown wires were 1.2 - 1.4 ohms.

2 of the other wires were 1.2 ohms and 2 were 0.2 - 0.5 ohms.

 

Reset the injector adjustment aswell. I was expecting all 4 to look the same once adjusted but one was showing more threads above the locking nut than the others (4 or 5 threads rather than 1 -2). Might not be an issue but nor what I expected.

 

Anyway  still has the same issue so will change the loom and see if that cures it.

I'm not clear on how you measured the resistances on the harness.

 

Can you elaborate on how many wires were present and their colours?

 

From what I can tell the harness in the head should have 5 wires, grey, red, yellow, white (injectors 1,2,3,4) and brown (ground).

 

The plug in/screw connector should be wired brown/red, brown/green, brown/white, brown/blue (injectors 1,2,3,4) and brown/yellow (ground).

 

Unplug the harness connector and measure between ground and each injector, all 4 should be similar.

 

High readings would suggest a poor spade connection at the injector requiring a wee nip for a better connection.  Don't rush out to buy a new harness unnecessarily.  Of course the injector may be bad so any suspect should be measured directly at the injector and compared to the original value to rule out harness/injector connection issues..

Edited 20 February, 20224 yr by MicMac

2 to each injector.

1 brown that goes to all injectors.

Then 4 individual wires that go to each injector, from memory red, yellow and 2 white with trace colour.

On 20/02/2022 at 21:56, MicMac said:

I'm not clear on how you measured the resistances on the harness.

 

Can you elaborate on how many wires were present and their colours?

 

From what I can tell the harness in the head should have 5 wires, grey, red, yellow, white (injectors 1,2,3,4) and brown (ground).

 

The plug in/screw connector should be wired brown/red, brown/green, brown/white, brown/blue (injectors 1,2,3,4) and brown/yellow (ground).

 

Unplug the harness connector and measure between ground and each injector, all 4 should be similar.

 

High readings would suggest a poor spade connection at the injector requiring a wee nip for a better connection.  Don't rush out to buy a new harness unnecessarily.  Of course the injector may be bad so any suspect should be measured directly at the injector and compared to the original value to rule out harness/injector connection issues..

The resistances were measured on the wires whilst connected to the injectors as you state and the individual wires when not connected to the injectors.. The readings were all over the place in both circumstances.

The harness has been changed for another and all the resistances are now equal when tested.

The problem remains, and still only occurs when the car warms up.

I've taken if to a local friendly garage who have put if on their diagnostics and the attached pic shows what the injectors are doing on tickover.

I did a video of them as well. And they are ranging as follows over a 30 second period at tickover (820 rpm).

Injector 1 ranges 2.33 to 2.52 mg/str

Injector 2 ranges 2 -1.39 to -1.53 mg/str

Injector 3 ranges -0.89 to -1.04mg/str

Injector 4 ranges -0.09 to 0 mg/str

 

None of that means a thing to me  but I assume it ain't normal.