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Rob, ASE Certified Technician
Category: Car
Satisfied Customers: 905
Experience:  30 years trade experience
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I have a 05 octavia 2ltr tdi elegance estate,I have just had

Customer Question

I have a 05 octavia 2ltr tdi elegance estate,I have just had the cam belt and water renewed, since I am getting about 10 miles to the gallon less, does the onboard computer need rebooting? and if so where can I get it done.
Submitted: 4 years ago.
Category: Car
Expert:  Rob replied 4 years ago.

hi and welcome to just answer.

The engine control module does not need rebooting.

after the timing belt was replaced did you notice any difference in performance idling and noise?

regards rob

Customer: replied 4 years ago.
No,performance as good as it was , just less miles per gallon. The car has been regularly serviced as per schedule .
Customer: replied 4 years ago.
No performance and every other thing as normal, just less miles per gallon. (Very noticble). I do 30 miles each way to work each day so I notice the miles per gallon.(I am an HGV) class 1 driver ,and I have had this car for the last 4 years and it was brilliant on fuel per mile.( not now though).
Expert:  Rob replied 4 years ago.

Hi Jimmy.

Have you had any warning lights on the dash no matter how brief.

do you know anyone who has a code reader with live data on it?

what is the current fuel economy mpg?

regards rob

Customer: replied 4 years ago.
There has been no warning lights on, the mpg at the moment is about 48/50 and I don't know what a code reader is. There is a VW dealer in the town where I live and they have a workshop I suppose I could take it there but I want some idea as to the problem. The garage I had the work done is not a dealer but a general garage, where I have had all my cars serviced and repaired so I don't think they have done anything wrong. I hope you can come up with an answer for me.
Expert:  Rob replied 4 years ago.

hi jimmy.

the timing belt replacement may be the issue the camshafts sprockets on this engine

have to be locked with a special tool the 3 centre bolts loosened this is to ensure that it is timed accurately even half a tooth out will not produce any fault codes but will affect fuel consumption.

there other items that can cause a reduction in fuel economy and need to be assessed using a live data reading via a diagnostic scanner this will also pick up any recent fault codes stored in the computers memory.

things to do next.

check the timing.

check the engine coolant temp sensor reading on live data at running temp to see it corresponds with the gauge .

check the mass airflow meter intake air temperature reading at running temp.

these are the main areas to check .

I will hit the answer button but you do not have to rate it yet and can continue to work with me on this.

regards rob

Customer: replied 4 years ago.
Thank you for your help I will contact the dealer to get my car booked in for the checks you have suggested.
Expert:  Rob replied 4 years ago.

I will look forward to your reply.

regards rob

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