Skoda Octavia 1.6i Ambiente 2003 52 Reg idling Problems

[Caesar]

Dear All

My Skoda has very poor idle problems intermitantly. The rev counter revs up and then drops suddenly un-controllably. It fluctuautes irratically when the revs are increased to 3000-4000 RPM. I have cleaned the throttle body by spraying injecter/ carb cleaner. When doing this the engine block light came on and the exhaust had a egg smell which dissapeared after a little motorway run and the light reset itself back to normal. Please can anyone advise what the problem maybe and how to fix it? Many Thanks in advance

 

[^neo^]

sounds like a problem with the cat or lambda sensor, which may also be linked to the coolant temp sensor

 

[Caesar]

sounds like a problem with the cat or lambda sensor, which may also be linked to the coolant temp sensor

Many thanks for your advice. The eggy smell has gone. The problem only seems to ocur when the car is hot however when it is cold, it works fine.

 

[^neo^]

Temp sensor is the cheapest thing to change and would explain the hot problems.

 

[Caesar]

Dear Neo

Many thanks for the reply, would the temp sensor affect the idle rev that much so the reves flucatuates up and down? The Car has only done 28000 miles from new.

How can I locate this sensor where would it be?

 

[^neo^]

The sensor controls the fuelling...... more fuel for when it's cold, less fuel when it's hot. If it gives a duff reading to the ECU then it can cause all sorts of running problems.
Not sure on a skoda, but on most vw's (same engine i believe) it is located on the front coolant hose flange (big water pipe which goes from radiator to top of engine)
Usually just held in by a spring clip, and should have 4 wires going to it. Under £20 from the dealer and a 2 minute job to fit. Make sure engine is cold and expansion tank cap is off before attempting to change it because of the water pressure!

 

[Caesar]

Hi Neo

I think I found the Temperature sensor which seems to be located in a plastic housing which connects to the Engine Block and the lower Radiator Hose is connected to this coupling, is this correct place for the sensor? How do I remove the 2 wire loom which goes to the top of the sensor as there is no clip or any means of prising it off? The sensor I believe is held in place by a Green Clip! Is this correct? PLeas advise how I can remove the sensor to replace it many thanks.

 

[^neo^]

Sounds like you have the right sensor, although most of them have 4 wires....... is there 2 sensors there? Has it got a blue or yellow plastic ring on the sensor?

Pull / wiggle & squeeze is usually the way to go. They can be a b1atch to do, so try pushing it fully on first. Clip should just flick out with a little screwdriver. If you're quick, you shouldnt lose too much coolant either

 

[Caesar]

Dear Neo

Many thanks, I ad a computer put on by a garage they diagnosed the temp sensor fault along with afault with the MAF. Both replaced, car passwed it MOT but when I was driving it the revs became erratic again so gragage had a qucik look and reset the fault codes after which evrything appears to be OK. Many, Many thanks for your spot on analysis really useful.

 

[Caesar]

Hi Neo

OOOPs!! Spoke to soon the erratic rev count after car is rev to 4000 rev plus has returned again after the MAF and Temp Sensor were replaced!

Any further dieas what the rpblem maybe? Many thanks.

 

[^neo^]

MAF is usually the culprit when you get to that sort of revs.
Even though it has been changed, you need to get the wiring checked to it aswell.
Other thing is the timing may be out, but think this is controlled by all the various engine sensors. Suppose it's possible the cam timing is out. Has it had the cambelt changed recently / ever?
Is it the revs that actually fluctuate, or just the rev counter?

 

[Caesar]

Hi Neo

The CAM belt has not been changed as car has only done 28,000 miles.

The Rev counter is what fluctiuates and you can hear the engine rev up and down and even feel it!

Only does this if the car is revved up and over 4000 revs but when it is cold it is fine.

 

[Caesar]

Dea Neo

Had the problem finaly resolved! Garage had to use aVW diagnostic computer which pinpointed the Lamda Probe as faulty as well as a faulty power steering sensor! Lamda sensor was replaced along with the power steering sensor, Faut codes were reset and hey presto Car revs are back to normal! Many thanks for all your help it is really appreciated.