Need some help with a TDi 130 PD

[Squeeguk]

Recently purchased a Passat TDi 130 '53' reg with 100k on the clock. Scanned with VCDS and it gave me error code 16685 - Misfire on Cylinder 1. Most of the info on the web points to the injector loom in the head which I changed today. This has had no effect, so seems like it was a waste changing it.

Problem is, the car seems to pull very well, loads of power, etc. but the idle is rough as anything and still getting the error code. Anybody come across this or have any ideas? Some have changed injector 1 with this issue and it still continued. At the cost of injectors, not too keen to buy one to try.

Any diesel experts out there or does anybody know anywhere I can take the car to to get it checked over?

[doylebros]

If your not wanting to throw money at it by fault finding by Substitution:-my checks for that type problem would be:-

Inlet manifold visual  - possible heavy fouling.

Tank lift pump - look to see if it's gauze is black - tandem pump seal

Tandem pump pressure test at idle

Compression test

Injector replacement to cylinder no1 or that injector sent for testing!

Found this info :-
One issue can be in the injector due to a wear issue that we are working on.

If the injector has excess internal leakage, at low rpms the ECU control of the injector can't compensate for this and begins to miss.

PD injector pressures at low rpms drop to around 300 bar and rise with rpm to a maximum of 2000 at 3600 rpm. There is a leakage pressure ratio and that ratio closely follows the balance values in Block 13.

Group 13 balance values in the ranges of 0 to 2.00 generally means the leakage ratio is close enough for normal control, beyond 2.00 and the car becomes erratic in terms of quantity, timing and delivery quantity control go out the window so to speak.

If the idle balance is in normal a range of 0 to +/- 2.00 the control system is working correctly and you probably have a nozzle or tandem pump related issue.

If you are getting an idle deviation of +/- 2.00 or greater you probably have a leakage related issue.


Hope this helps you !

[Squeeguk]

Excellent info. Many thanks.

Injector 1 is constantly at 2.99, regardless of revs. The odd thing is that injector 2 is at 3.01 at idle with no error codes, but this comes down with revs. Injector 3 and 4 are spot on.

Do you know where I can send the injector/s to be tested or refurbed?

I will be giving it a major service tomorrow or Friday, time dependent. I will when I get a chance, be cleaning the inlet manifold and the EGR valve too. Trying to get rid of all other possibilities. But from the info you have posted, it definitely sounds like an injector issue then.

This was supposed to be a cheap car to see us through for the short to mid term, but it looks like it's going to end up costing a packet now. Like I say, the car feels 100% while driving, it's just the idle which really gives the kidney's a workout.

[Marshall]

Have you looked at the camshaft?
Just incase a cam lobe has worn away and the injector is trying to compensate for it.
Cams do go but I thought it was more the 150 pd
Worth a look.

[Squeeguk]

Yep checked that yesterday, cam looks fine.

[Marshall]

Could you change injector over to another cylinder and see if it changed cylinder?

[doylebros]

Check the tank prepump - like I said no cost involved and if it's black the seals gone on the tandem pump!

[Squeeguk]

Could you change injector over to another cylinder and see if it changed cylinder?

I thought of doing that, but apparently you have to buy new bolts, etc. etc. Might just end up doing it though. Wife is not happy, she refuses to drive the car. Guess she's spoilt with the smoothness of the T-FSi, lol.

[Squeeguk]

Check the tank prepump - like I said no cost involved and if it's black the seals gone on the tandem pump!

Will check this too, thanks.

[Squeeguk]

Well did some intense investigating today. Turns out it needs a new camshaft. Check out the cam lobe on injector one.



Ah well, a cheap car turns out to be expensive once again. I swore I would never do this again, lol. Should save a few hundred quid doing it myself, but then again, all the parts are going to be around £600 odd. Might as well do the cambelt and water pump again.......

[four!]

I see darkside list camshafts and kits now, Maybe worth a look :)

[Squeeguk]

Yeah, thanks, saw that, but very pricey though. I managed to get a proper forged heavy duty cam, cam seal, bearings, hardened followers, full cambelt kit, water pump and rocker cover gasket for less than Darkside sell the camshafft kit on it's own. And all this from a very reputable source.