17656 injection start regulation control deviation

[abenga]

Hello,

I'm new to this forum, so please excuse my eventual mistakes .....

I have a problem with a Skoda Octavia 1.9 TDI, ALH engine, 90 hp, year 2006.
Since few days ago the engine check light is on, but the car is running smoothly, no loss of power no matter the speed or rotation per minute. Also I couldn't notice any strange sound from the engine, nothing that would lead me to understand that there is a problem. The car has only 40.000 KM.
I went with the car to the mechanic, and the error displayed is:
17656 injection start regulation control deviation.
Now, they told me that the "deviation" (I hope it is the correct word) is not correct, it is much higher then normal. They told me the the reasons could be 2-
- modified manually - not the case as no one touched the car's engine since one year when the oil and filters were changed.
- modified by the injection pump which is not functioning correctly.
They have ajusted the deviation back to normal values, the error is gone and the light is off. I've been told that if the error comes back again, then the injection pump is faulty and needs to be replaced.
Now, after the deviation has been ajusted, in the morning the engine starts with a little dificulty, but after it works just fine.

I just want to ask if someone of you has ever experienced this kind of issue and possible if you can give me some help on this, as I cannot believe that with a faulty injection pump the car can run perfectly.

Thanks in advance!

[Crasher]

The valve timing needs to be checked, adjusted as necessary and then the Commencement Of Injection (COI) checked/adjusted again and see how it goes. When was the timing belt last changed.

[abenga]

No belt has ever been changed until now.

[Crasher]

Well it is due next year as the interval is every four years so I suggest the belt is changed now.

[abenga]

I have been again to a mechanic .I have been told that the timing belt has been checked, it has no problems. Timing valve is also fine. What they have noticed is that the fuel temperature measured by the injection pump is wrong, meaning about 140 degree (it is shown in Vag-Com in the low-left corner of the deviation graphic.
The point is that after they have adjusted the deviation to about 60, after they start the engine several time the deviation (as shown in the graphic) rise up to 120 again.
They said that the electronic part (software) of the injection pump which is wrong measuring the fuel temperature, and as conclusion it is faulty and needs to be replaced.
Can you tell if this can happen like this, and if yes, can I replace the electronic part of the pump, or the entire pump?

Thanks in advance!

[Crasher]

The fuel temperature sender in the pump is available separately (part number 028 906 040 C) but it may be telling the truth. To access the sender you have to remove the special bolt on top of the pump and you must know what you are doing to change it.

[abenga]

Thanks for advice .... but it looks like fixing the pump costs more then getting a new one. I started to search the internet for a fair price for this pump, in Romania is about 1200 E which is too expensive ....
Can you please let me know which is the part number for this pump, and maybe if you know some specialized sites selling engine parts at fair prices?

Thanks in advance!

[Crasher]

How would we know the number, it is not a car we get? The sensor costs £19 which is about £25 Euros and takes half an hour to fit, how can that be more than a new pump fitted? Take it to a proper garage, the ones you are using doesn’t sound qualified.