My PD130 Polo GT TDI (BLT engine code) has developed a missfire, a lumpy idle and the whole car shaking when the revs are increased in any gear. I took the car to a local VW dealer near where i work, i got told the camshaft is damaged, £1300 for a new one + fitting. Not satisfied with this i have used the search facility on here and read about injector wiring looms going faulty. I have removed the cam cover from the car, i can see no visable signs of wear or damage to the camshaft, lifters, injectors and no debris inside the head. I removed the injector loom and buzzed it out with a multimeter for continuity and all seems fine. Upon cross chechcking the part numbers for the injectors i realised that ASZ code injectors are fitted. Is this of any cause for concern or are they interchangeable?

Would it be worth the £52 for a new loom from the dealers or would that be a waste of money and should i be looking at removing the injectors to have them tested and/or replaced if necessary?

Help and advice greatly appreciated

Link to video of car running here

Edited 17 August, 201114 yr by Phill W

The BLT engine is in essence an ASZ with a different EGR setup to meet EURO IV emission standards

You got the loom ordered then! Weird about the part numbers on the injectors though!

U want to fit a new loom anyway once they have been disturbed sometimes they become tempramental. Fit a new loom try starting it. while cam.cover is off.check the cam lobes for pitting. That is one of the signs of chocolate camshaft.

Little update: Impedance of injectors measured and all 4 were the same, new injector loom fitted, rocker cover back on, fired her up and still the same :(

Thinking it might be chocolate camshaft syndrome :'(

Chocolate cam is pretty obvious when you look at it. Scored lobes, and there will be deep circles carved into the tops of the lifters. If they look and feel smooth it must be something else. Have you ran a VCDS scan to show its not just a sensor?

PS: I have a set of 4 injectors with barely any mileage on them from a 2 litre 8 valve TDI which look identical to the "AL" injectors of the PD130 engine, but they end in "BJ" - should you ever find there is a dodgy injector unit.

In addition, can you say how bad misfiring is at idle, and how it improves/worsens with revs/which gears used. I just want to rule out the dual mass flywheel shaking to bits....

Have had the rocker cover back off today (the car is dumped in the back carpark at work), cleaned the lobes and the lifters, from what i can see there is little wear on either. I have not ran a VCDS scan as i do not have this nor do i know anyone local with it :( I was hoping the dealers would have done this when it went in :no:

The misfire at idle sounds like the car is running on three, there is an awful lot of movement on the engine and with the throttle applied it does worsen. I have a video clip of this i took using my phone, will see if i can upload it and post the link.

Could be injector failure, but that is pretty rare. Usually it is the loom which is a more common failure. Hopefully the bottom end is OK but the only way to check that is to remove the head....

What mileage has it done?

Kev

If you can post some pictures up of the cam and well see if we can spot anything you might of missed

That was my next thought, removed the injectors and see if i could send them off for testing.

The car has done 49k, the cambelt was changed only a few hundered miles before i bought the car.

I will take my camra to work with me tomorrow so i as i can take detailed pics of the lobes/lifters as i've only my camra phone on me.

At 49k cam wear shouldnt be an issue.

Has it done it since you bought the car then?

Kev

Is there any service history with the car? If so what grade of oil has been used and how long are the intervals between oil changes.

We think its the lift pump in the tank - it seems to have been messed with!!!

As above, when i bought the car the rear seat base was not fitted properly and i remembered this so had a look at the lift pump. I'm pretty confident that it has been out before as there is evidence that suggests this (broken clips on cover, connector block damaged).

The car started playing up 300 miles after i took ownership. It did have full VAG service history but the longlife oil box has been ticked yes and no a few times :S

Currently no further forward with this :(

I have uploaded a video of the car running and have put the link in the first post (please ignore the boost pipe blowing off while revving it, some idiot forgot to put the retaining clip back in )

Should have bought a VRS

Edited 17 August, 201114 yr by Phill W

Hmm - Weird - sounds like a miss fire! It couldnt be a timing issue??

Oh dear, that looks like what mine was like. And it's not good news as mine was a cracked piston.

Any pressure in the head, leaking from the crank case breather?

check injector values in mbv block 11 iirc, should show if one cylinder is out.

Dragging this back up again :no:

Car has been with a local Skoda dealers, no compression on number 4 cylinder. Now, what would you guys recommend doing? Are there any options for increasing displacement on these engines if the bore is damaged or is that not the done thing? Just trying to turn a negative into something positive here :(

Dragging this back up again :no:

Car has been with a local Skoda dealers, no compression on number 4 cylinder. Now, what would you guys recommend doing? Are there any options for increasing displacement on these engines if the bore is damaged or is that not the done thing? Just trying to turn a negative into something positive here :(

You can buy 2.0 PD pistons form Darkside Developments. You would then have to re-bore to 2.0. The pistons are £700 for starters...It wont be cheap!

More than likely a cracked head, doubt the bottom end is effected.

More than likely a cracked head, doubt the bottom end is effected.

have a spare oem one on fleabay at the moment if the head turns out to be cracked.

DId you ever sort this? I have a lumpy PD130...