Revs Are Jumping Like Crazy !!!

[james in Norway]

Can someone please put an end to my nightmare ????

I have an Octavia 2000, 1.6 sxi 100bhp.

For the last 2 weeks my revs have been flicking up and down from 1000 -2000 revs, if i am driving at a set speed...say 70 miles an hour it is perfect, put sson as i pull up to a junction and press in the clutch i get the revs plicking up and down all the time !!!

I get the same problem if cold, warm or hot !!! i have had of and cleaned the throttle housing, i have tried a new throttle housing, i have changed the air mass and pipe, i have checked all pipes loose contections and battery terminals, i have had in in a garage 2 weeks and they cannot work out what is wrong with it, it has a second fault, If i sit still and hold the throttle on say 3.000 rpm then release it slightly it jumps back under my foot (the peddle) and the revs RAPIDLY fall to 1.000rpm then back up to 3.000, this is so anoying when you are on a motorway and you back of the power just a little and the car power drops then kicks back in with a jolt.

The car has been perfect up untill now with no problems, had it for 18 months and love it, but this problem is pulling out my hair,

When i pull up at a junction people think i am a boy racer reving the engine !!!

I am prety good with mechanics so any advise will be sooooo appreciated.

It is not using any more or less fuel than normall, all my miles are done on the motorway, and yes i have tried different actaine fuels with no difference.

Please help before it spends a 3rd week in the garage.

All fault codes have been read nd cleared, with no help

HEEEEEEEEEEELP ME !!!!!!!!!!!!!!!

[KenONeill]

Is the temperature gauge behaving correctly?

[james in Norway]

the temprature gauge reads the same as always, it sits exactly in the middle, and the outside temprature reading is perfect too, i did wonder about the temp sender cousing a problem but the garage said that they checked its resistance and it was fine, could it still be faulty??

[KenONeill]

I don't think so. The reason I asked was that my dad had similar symptoms on one car (revving its head off, temp guage all over the place), and the problem was the sender.

[ap0gee1978]

I've never had it happen to me, but my first thought was that it sounds a little as though the EPC has gone into limp mode, where it holds the revs up high so you can 'limp' to the nearest garage. But then I re-read it and saw what you put about it happening when the clutch pedal was in, which made me think a fault with the clutch switch. A diagnostic check should confirm / discount this...

Hope this helps!

[james in Norway]

any other ideas on what it could be, is there a way of checking the sender myself?

I need to go into the garage soon as my head hurts...

Thank you for your help, i may just buy one and see if its too fault....if you have any other ideas or ways of testing these parts it will all be so helpfull, cheers m8ty.

[ap0gee1978]

If the fault was on a Fabia, it would be relatively easy, as the one sender provides a signal to both the ECU and the dash gauge, and so a dodgy sender is usually revealed by the gauge sitting at MIN even when the engine's warm. The Octy has a twin sender AFAIK (one element for each function), so the only thing I can suggest is a prod with a multimeter or a session with a diagnostic reader...

[james in Norway]

in reference to the man saying about the clutch in, it happens even when the car is in neatral, the only way to bring the revs down to a settle is too put the car in gear and stress the engine with the breaks on, then let the car almost stall and then the revs will sit low, but as soon as i touch the acellerator they jump back up, and down, and up and .....you get the picture

Ooooh i forgot to mention that if you put your hand around the back of the throttle body when running you can feel the centre of the shaft of the butterfly valve clicking backwards and forwards...hence the revs up and down, this it what makes me think it is being sent a eletrical signal that it shouldent have, and the new throttle boday does just the same !!!

Bugger me my hair is falling out...

[ap0gee1978]

Have to point out that I'm assuming the engine management on the Octavia is the same as on the Fabia, but the reason I mention about the clutch is that the clutch switch sends a signal to the ECU which cuts the power when the clutch pedal is in (for emissions reasons). Therefore, if the clutch switch is faulty, it might cause the problems you describe whilst the clutch pedal is in...

But it's only a stab in the dark???

[james in Norway]

If the fault was on a Fabia, it would be relatively easy, as the one sender provides a signal to both the ECU and the dash gauge, and so a dodgy sender is usually revealed by the gauge sitting at MIN even when the engine's warm. The Octy has a twin sender AFAIK (one element for each function), so the only thing I can suggest is a prod with a multimeter or a session with a diagnostic reader...

do you know what settings i should put on the multimeter, i have a nice shinny new one in my garage so now is a great time to test it out...

also where on my octavia is this second sensor ????

thanks...

[ap0gee1978]

do you know what settings i should put on the multimeter, i have a nice shinny new one in my garage so now is a great time to test it out...

also where on my octavia is this second sensor ????

thanks...

You'd be measuring resistance on the multimeter, although I don't know where on the scale you'd start (kiloOhms?) Also, I can't remember off the top of my head whether you'd need current going through it to get the meter to give a reading, in which case it could be a bit tricky!

As for there being two sensors, I'm sorry for the confusion - both elements are inside the same sensor unit (4 pins = 2 for each element). I don't know which pin is which, but a bit of a search on here may help.

OTOH, the sensors on their own are pretty cheap off ebay, so it might be worth swapping it without testing it (although this will mean you don't get to use your multimeter! )

[james in Norway]

I have tried to play with the clutch switching allready as a stab in the dark, but with no luck, the power droping back (revs) happens even while at motorway speeds....

See this is a hard one and its so anoying not nowing what it is as the fault codes are not showing...

Everybody that is replying to me, you are all great and the help that i am getting is fantastic, any more thoughts today ?? i will take any thoughts striaght to the inside of my garage and inject them into my car......one idea will come and it will be fixed and i will have a big fat smile on my glum face..

keep the thouhts coming...thanks...

[georged30]

i had the same problem and after a visit to my local dealer the clutch switch was replaced and now everything is fine:thumbup:

[james in Norway]

to the man who had his clutch switch replaced, how much did you pay for the part and do you know where it is, i have fiddled with what i thought was the clutch switch but maybe i got it wronfg, do you know where and how to check its working correctly....can i get out my multimeter again:)

Look forward to your reply....

Oh and a new question.....This one is going to make me look stupid...how on earth do you get out the spark plugs, do you really have to take off the inlet manafold, or am i being dumn??

cheers...

[ap0gee1978]

to the man who had his clutch switch replaced, how much did you pay for the part and do you know where it is, i have fiddled with what i thought was the clutch switch but maybe i got it wronfg, do you know where and how to check its working correctly....can i get out my multimeter again:)

This is the clutch switch for a Fabia, and I can't imagine they'd have a different part for an Octy (although things might look a bit different down there.) You'll need to remove the panel under the steering column, then 1. disconnect the switch from the wiring, 2. twist it anti-clockwise, 3. pull it out:

Can't help with the cost or the part number, or indeed the sparkplug question, although when the coilpacks were replaced on my old Renault (which sit on top of the sparkplugs), the AA man didn't have to do anything like remove the manifold - might be different on an Octy, though...

Oh, and there's no reason you can't test the old switch with your multimeter before you order a replacement!

HTH

[james in Norway]

great picture, thanks...

i will have a second chance to use my multimeter, yeeeaaaaa....boys and toys...

i know i am asking a lot but....do you know what would be the best setting to use on the meter and what sort of reading i should get to see if its correctly working, should i test it with engine running and pluged inn, or in my hand unplugged....hope you not thinking dumn *** in the back off your head...

looking forward to your thoughts...

[ap0gee1978]

The best way to test if a switch is working correctly is to check its resistance - it chould be very high when the switch is open and very low when it is closed. As I mentioned before, I can't remember whether it'll need power running through it for the meter to work, but if you can reach the contacts of the switch with the probes of your meter, then you should be OK to test it while it's still in the car (with the engine running and the gears in neutral, obviously! )

[james in Norway]

damn and i wanted to stear with my feet and do it whilst driving, ha ha ha , just kidding.

Thanks again for the tip, i will try this as soon as work is over, maybe it will flick up and down on the meter with the engine revs....lets hope this is the problem, i will let you know, cheers...

[DGW]

You seem to have tried a lot of things but I don't see any mention of having carried out throttle body alignment, which solved a similar problem I had with my Felicia 1.6. I presume that you had this done when you changed the throttle body?

Ross-Tech: VAG-COM: Throttle Body Alignment

[james in Norway]

to the best of my knolage yes, as the garage checked it afterwards, is there a manual way to do this with out the computer???

also do you have any other suggestions, like the clutch switch etc, just incase it is not your suggestion. I am trying to get as many possible problems so i can put my head under the bonnet and solve this problem.

Also do you have any ideas on spark plug removal comment above?

Thank you all you Skoda lovers, what a great site...

[james in Norway]

Well, what a night i had.....

I have tried and tested the following.

Clutch switch...good

Temp Sender...good

New throttle body...good

New air mass and pipe ...Good

Battery connections and earth lead...goog

Complete reset on engine and throttle body...good

different octain fuel...good

Fuel injector additive...good

as far as i know i have tried all and everything...and i still have the same problem !!!

The revs still flicker between 1.000 and 2.000 revs

And if i lift of my foot off the acelarator at any engine rev speed i get a rapid drop in revs and then it picks back up to the befor revs....it pops back under my foot, i can feel it moving the butterfly valve if i put my finger on the shaft at the back of the throttle housing....it must be electricle fault but how do i find it out....even the garage is stumped...

PLEASE someone give me some out of this world tip or hint to my car problem...:confused:

THANK YOU PEOPLE....look forward to your responce...

[ap0gee1978]

I'm afraid to say, James, but I don't think you're going to get to the bottom of your problems without using a diagnostic reader - either paying for a garage to look for you, getting hold of a VAG-COM cable and using VAG-COM on a laptop, or buying a handheld reader - you should be able to get an idea of the relative merits if you have a search on here...

HTH

[james in Norway]

I wish it was that simple....

Its been in a garage VAG approved, and has been diaganosticly tickled for 14 days with out any luck, hence my desparation on the forum.

I will sit in a corner and cry like a school boy who has lost his best toy (toy car of course)

I know i am pushing it but any...any...any ideas will still be appreciated, even if they are sugestions of setting fire and kicking the car...

A very down Skoda owner.....

[james in Norway]

OOOhhhh the big sigh on my face......its no good, i think i will burn the car, no change with a throttle reset, i really am weeping, so much that i am thinking of trading my baby in for another Skoda......

If any one can give any more suggetions it would save me doing somthing bad to my car with a hammer.......

But a big thanks to all who have helped me so far in this BIG high revving adventure down insanity lane...:confused:

[KenONeill]

Completely off the wall, but can you get trial remaps in Norway? About the only thing left that I can think of is that the map's scrambled (and I've never heard of this happening before and the engine still running at all), and remapping is cheaper than a new ECU!