BXE Injection deviation under warm engine

[Bushas]

Hello to everyone,

Patient high mileage ~200k, 06 plate octavia DSG 1.9 tdi PD BXE. Recently i noticed increased fuel consumption on warm engine  while idling about 0,9L/H and sometimes when starting  warmish engine misfire with blue/white smoke occurs. So i took a ride with vcds and I saw that injection deviation increases while engine warms up.

Cold engine which i think is absolutely fine and idle consumption is no more than 0,7l/h :

 -0.31 mg/str  Injection Quantity Deviation Cyl. 1
  -0.05 mg/str  Injection Quantity Deviation Cyl. 2
  0.19 mg/str  Injection Quantity Deviation Cyl. 3
  0.14 mg/str  Injection Quantity Deviation Cyl. 4

While on warm engine (coolant temp above 80C) idle consumption always above 0,9l/h:

  -0.73 mg/str  Injection Quantity Deviation Cyl. 1
  1.13 mg/str  Injection Quantity Deviation Cyl. 2
  -0.56 mg/str  Injection Quantity Deviation Cyl. 3
  0.16 mg/str  Injection Quantity Deviation Cyl. 4

About half year ago timing belt was changed and valve stem seals, month ago coolant sensor went crazy showing on dead cold engine 130C~ so i replaced this one also.

First i thought dead injector cyl 2, but it's perfect on cold engine. Attached vcds log for more info.

Any ideas?

Thanks in advance

 

 

 

LOG-01-013-003-007.CSV

[silver1011]

Were there any fault codes logged when you had VCDS hooked up to the car?

[Bushas]

11 hours ago, silver1011 said:

Were there any fault codes logged when you had VCDS hooked up to the car?

Yeah there was one, but i dont think it's related somehow:

005784 - Please Check DTC Memory of Steering Wheel Electronics 
               P1698 - 001 -  - Intermittent
             Freeze Frame:
                    Fault Status: 00100001
                    Fault Priority: 0
                    Fault Frequency: 1
                    Reset counter: 255
                    Mileage: 266124 km
                    Time Indication: 0
                    Date: 2000.00.00
                    Time: 07:02:11

             Freeze Frame:
                    RPM: 1512 /min
                    Speed: 30.0 km/h
                    Load: 27.1 %
                    Voltage: 14.52 V
                    Bin. Bits: 11101000
                    Bin. Bits: 00000000
                    (no units): 0.0

[silver1011]

Yes, I am pretty sure the stored fault code is unrelated...

 

[Bushas]

Is it possible that injection deviation increase due to bad timing?

[Golf-Fiend]

Why are you worried about it?

How does it drive under normal conditions?

How much is economy affected?

Does it have a lumpy idle when hot?

 

Those figures are not massively out. When my injector died it was showing +/- 3.99mg/str which is the maximum value.  It only developed a lumpy idle when hot and the AC load was on. Economy was not really affected as mg are very small amounts and at operating revs the injectors are firing so rapidly it makes little difference.

 

When I had it fixed the change in economy was barely noticeable though the idle was smoother.

[Bushas]

10 minutes ago, Golf-Fiend said:

Why are you worried about it?

How does it drive under normal conditions?

How much is economy affected?

Does it have a lumpy idle when hot?

 

Those figures are not massively out. When my injector died it was showing +/- 3.99mg/str which is the maximum value.  It only developed a lumpy idle when hot and the AC load was on. Economy was not really affected as mg are very small amounts and at operating revs the injectors are firing so rapidly it makes little difference.

 

When I had it fixed the change in economy was barely noticeable though the idle was smoother.

I'm worried as idle consumption has increased from 0,7l/h to 0,9l/h. Lumpy idle observed only on cold engine for about 20s., but there was few times when after commuting for long time and then after one hour stop i started the engine and there were pretty heavy misfire with cloud of smoke so i think it's somehow related related. Also as you can see from the log sometimes deviation reaches 1,8.

[Golf-Fiend]

2 minutes ago, Bushas said:

I'm worried as idle consumption has increased from 0,7l/h to 0,9l/h. Lumpy idle observed only on cold engine for about 20s., but there was few times when after commuting for long time and then after one hour stop i started the engine and there were pretty heavy misfire with cloud of smoke so i think it's somehow related related. Also as you can see from the log sometimes deviation reaches 1,8.

 

Sounds like you have a "leaky injector" where after use it will dribble a little bit into the cyclinder and this burns off when you restart. Mine was like that for over a year before I got it fixed but as I say it didn't cause me any real issues.

 

I'd not be too worried about "idle" consumption. From what you describe this equated to 200ml per hour of idling. Do you set your car idle for long periods?  I'd be more concerned if my driving consumption changed a lot. 

[Bushas]

My daily commute is mainly through city traffic, so it contains lots of traffic lights therefore this increase is not nice to have , about overall consumption is hard to tell cuz  outside temperature is always about 0 C, also  winter tyres has impact, so i need more time, but yeah there is no drastically increase in overall consumption.

What have you done in your case? Pull out injectors, test and replace if needed? Can they be restored?

[Golf-Fiend]

10 minutes ago, Bushas said:

 

What have you done in your case? Pull out injectors, test and replace if needed? Can they be restored?

 

Mine was a BKD engine but still similar PD injectors. I think there is little that can be done in terms of fixing them. New ones from a dealer costs a fortune. Probably half the value of your car!  Usually PD injectors are very reliable so I bought a 2nd hand one from ebay and had a friend who had an injector test kit. He tested it for me and it was fine so I got my garage to install it for me.

[Bushas]

1 hour ago, Golf-Fiend said:

Why are you worried about it?

How does it drive under normal conditions?

How much is economy affected?

Does it have a lumpy idle when hot?

 

Those figures are not massively out. When my injector died it was showing +/- 3.99mg/str which is the maximum value.  It only developed a lumpy idle when hot and the AC load was on. Economy was not really affected as mg are very small amounts and at operating revs the injectors are firing so rapidly it makes little difference.

 

When I had it fixed the change in economy was barely noticeable though the idle was smoother.

 

45 minutes ago, Golf-Fiend said:

 

Sounds like you have a "leaky injector" where after use it will dribble a little bit into the cyclinder and this burns off when you restart. Mine was like that for over a year before I got it fixed but as I say it didn't cause me any real issues.

 

I'd not be too worried about "idle" consumption. From what you describe this equated to 200ml per hour of idling. Do you set your car idle for long periods?  I'd be more concerned if my driving consumption changed a lot. 

Thanks mate will see how it will progress during time.