Hello again, I know this is topic well discussed but after searching and doing some testing I still don't have a conclusive answer. I have a mk2 FL octavia with a 1.6 cr tdi (cayc). It has 256.000km and it's been knocking for some time. Every 6 months or so I would do a purge temporarily fixing the issue until last saturday. I did a purge and checked the adaption values for the injectors (codes printed on their top). To my surprise the values were the same as the injectors but with a 1 added to the end of it. 

 

The next day I was on my way to work when the car felt down on power and started smoking like crazy (white). It was quite spectacular. There was no engine/glow plug light on but I barely made it back home. That night I tried a Adjust minimum deviation value with VCDS but it didn't work. Went out for a drive and looked at the inyector values and saw them being adjusted. Now the car is running again. Smoking after every cold start and knocking under load. I ordered 2 new injectors but I'm not sure which to replace.

 

My deviation values have returned to the same ones before the purge:

- iny1   0.5154

- iny2  -0.3005

- iny3  -0.7476

- iny4   0.6367

 

Injectors 1 & 4 seem to be blocked or 2 & 3 are leaking. Any ideas on how to determine which to replace? I don't want to be swapping injectors as the retaining bolts are TTY and the copper washer is supposed to be used once as its a crush washer. Could the cause be leaking injector seals (I can't hear any hiss near the engine though) or failing glow plugs?

 

The deviation values for the engine in cold state (20°c) are:

- iny1   15.108

- iny2  -24.652

- iny3    -0.8919

- iny4   20.103

 

My car has a stage 1 remap and EGR + DPF off (I gutted the DPF). It also had a DMF failure last year and the clutch pack replaced (prior to the remap).

 

Thanks in advance!

I forgot to add:

- the car smoked white after every cold start from before (since the dpf gut).

-I didn't change the injector coding before the break down. I did change them after (by removing the extra "1" on them).

-Now the injector codes have a "0" added to the end of each (not added by me). I believe this is due to the engine "learning" this injectors, not sure though.

Update:

I replaced the injectors that seemed to be clogged (2 & 3) with new units. The part number is different (last letter is S instead of B ) as its the updated part. MPG improved dramatically and knocking is almost completely gone. I left in place injectors 2 and 3 but now the deviation values are approximately:

- iny1  -1.8

- iny2  2

- iny3  2

- iny4  -2

 

I'm guessing that 2 & 3 are clogged in comparison to the new (1 & 4) injectors. I will try to clean with an ultrasonic cleaner the injectors that are out now and see if I can improve this further. Diesel purge did not help with these injectors.

 

 

If you have seen improvements i think a complete set of injectors might be the answer, it would be interesting if you had done a leak off test to see if that the results of that tied up with your deviation values that were off with the rest.

Ok, so I've done about 3500km (2000miles aprox) with a 1800km trip through the atacama desert without issues. Mpg was improved and engine feels stronger specially at the bottom end. 

 

I still haven't replaced the 2 old injectors but after a quick look at the deviation values I suspect that only inj 2 is clogged right now and inj 3 seems ok. I don't want to buy another pair of injectors as they are very expensive to me. I spend almost 1000 pounds importing 2 new injectors after customs and taxes. This was the cheapest combination I could find.

 

It would have been ideal to do a leak down test but I couldn't find adaptors for the injectors.

 

I have a new issue now: There are "dead" spots around 3500 and 4000 rpms at 4th (on a hill climb) and at 5th gear when trying to pull. I belive it can be 2 things:
-Torque being limited (according to vcds, I logged a run that showed "torque limiter: 280nm" (aprox) and "nominal torque: 277nm" (aprox too)).

-Learnt values of the old injectors haven't been reset (injectors were coded in correctly). I'm not sure how to reset these. I already disconnected the battery for some hours without any luck.

 

Any ideas? DSG remap? hahaha

What to do if the correction values aren't accepted by VCDS - error message "oiut of range"?