Hi all 

 

I bought a used Skoda Octavia 1.6 TDI with 40,000 miles back in August. I have had an issue with it ever since purchase. 

This issue is as follows: If I'm sitting at idle with foot down on clutch at a roundabout for example.

If I'm sitting for around 10 seconds or longer the revs spike downwards for a brief second the return to normal and will repeat every 10 or so seconds.

The car has gone back to the Skoda garage that I bought it from 3 times now and they have had it for the last week but can't find anything wrong. They garage have never seen the problem before and don't know what to do next.

 

Has anyone else had the same issue and potentially shine some light on the situation?

 

Many Thanks

One thing to help us the great unwashed of Briskoda Land - is to get a scan of your car to see if it is throwing up an error on the CANBUS network.  Post your scan of any errors here.

 

You will need to find someone close who has a VCDS or ODBEleven scanner.  An investment of £60 will get you a starter pack on ODBEleven (you'll need an Android or Apple phone though).

 

Couple of things to look at first:

 

1) Servicing - I am assuming all the basics are good - oil is good (was it serviced recently??).  A thought on this one; is one of the air-lines or the air-filter housing loose?  An air-leak will cause the car to run lean.

2) Check the air filter - is it dirty?  If so, replace ASAP as that will mess up the performance.

3) You might have a dodgy glow-plug - they do and can fail.  A scan of the CANBUS network will give us that info.

4) Fuel - you might have a dodgy batch of fuel.  My TDI's (adminitely all 2.0 vehicles) - are terribly sensitive to poor quality fuels.  If you are filling up with supermarket fuels, might I suggest a tank of decent branded go-go juice (something like BP, Esso) as these places put in additional additives into the fuel to help the burn process. 

5) Do you drive on short-journeys?  If so, this is NOT good for the TDI's.  Find a nice fast road (e.g. the M25) and take it for an Italian tune-up (the car needs to be at 2350rpm for period of about 15-20 miles for a good re-gen to occur).  The car needs hot engine conditions to regen itself and keep the engine in fine fettle.  If my TDI is feeling sluggish, I tend to drop it into manual and leave it a gear lower and let it clear itself out.

 

Many thanks

 

I second the above. Run the car down to fumes, fill up with half a tank of Shell V Power or BP ultimate diesel (just with them having more detergents in them), take it on a road where you can keep the engine speed high and constant, to keep the exhaust gases high.

The other thing to keep an eye out for would be to take note of the smell of the exhaust fumes when you get out your car. If it's a strong smell then you're car is trying to do an active regen. You're on a hiding to nothing if that isn't allowed to finish.

 

@varaderoguy I wouldn't say there would be a glow plug issue. They're only used in the initial start up of the engine when it's cold.

1 minute ago, tunedude said:

 

@varaderoguy I wouldn't say there would be a glow plug issue. They're only used in the initial start up of the engine when it's cold.

Agreed with you for older cars, but the glow plugs do assist with the burn process (especially if the car is running cold). Intermittent glow plugs can cause all kinds of bizzare running, so it is best to get it checked out. A scan of the Canbus network will give us all direction.

Hi all, thanks for the reply.

The car is not producing any fault codes at all . I also drive for about 2 hours a day in it plus along the motor way with good fuel in the car. 

The latest I heard from the garage is that the ECU is going to be re flashed.

My car had idles at 750 rpm when out of gear with hand brake on. As soon as you start to depress clutch to engage gear, the revs automatically go up to 1000 rpm. Its an anti stall device. Done it since new....Sept 16 66 reg, 46000 miles. 

Hi all

 

Thank you for the replys. My car has since been in to the garage another two times. As the issue is still present.  Second time they found a faulty exhaust temp sensor and now on the third visit I have been told it's the secondary coolant pump. What does this do?

 

Would the secondary coolant pump playing up cause issues with revs at idel causing them too spike?

 

I love the car but this issue is doing my head in.

 

It might be worth asking the Skoda garage to update all of the modules and see if that helps.