Hi all, I have just recently bought an Octavia Elegance 4x4 T 2001 and this is the first post for me, so hope its in the right place :0)

Couple of questions if i may to the better experienced octy owners.

1) I have just put my alpine head unit in the car and all works fine, except for the dimmer when i turn the headlights on, does anyone know which wire in the cars loom is the wire that controlled the brightness/dimmer on the original headunit?

2) I have replaced the standard DV with a Forge one, replaced the spark plugs with Bosch super 4's, and changed the air filter for a K&N panel filter. All was ok until after i changed the head unit, since then the CEL has been on, the car runs fine except for now and again it almost kinda wants to stall, the revs drop to about 500 then pick up to 800-1000 again.

I had heard of people saying that oil from the K&N filters can affect the AFM but the chaps at Regal Motorsport assured me it would be fine.

Does anyone have one of the VAG COM units near Fareham Hants and would be willing to have a look at the codes please?

Thanks in advance for any answers,

Richie.

I don't think the Alpine units dim, mine doesn't anyway (maybe because its a cheap model) I'd suggest doing a throttle body clean

blimey thanks for the fast reply...

The Alpine was £500 when i bought it, and does dim, was in my trusty T5 before and the dimmer wire was built into the loom, but seems the Skoda one is on the seperate connector that controlled the CD player in the boot.

As for the throttle body cleaning, i read somewhere that if you do this you should'nt disconnect the electrics from it, otherwise you need to get it reprogrammed VIA vadis, but surely it should be ok to disconnect otherwise it would need doing every time you disconnected the battery??? confused by that :0)

you don't need to disconnect any elecs, I got my missus to sit in the car with the ignition on with her foot on the throttle, this will open the valve and make it easier to clean. After cleaning mine the car drove 10x better.

you don't need to disconnect any elecs, I got my missus to sit in the car with the ignition on with her foot on the throttle, this will open the valve and make it easier to clean. After cleaning mine the car drove 10x better.

aha great idea, but how will she fetch me beer and press the pedal at the same time? hmm, move the fridge outside maybe?

for all the people that think you need vagcom when you disconect the throttle body try ad disconnect it then reconnect and see what happens lol it works just fine no need to use vagcom atall

p.s you need to do a vag com check before you do anything else this will give you an idea. prob a vac leak get the fault codes read

What Forge DV did you fit? Wasn't a split-R was it as they need adjusting properly otherwise they can cause a boost leak. There could also be a boost leak if the hoseclips weren't tightened right up when changing the DV. When you fitted the K&N did you unplug the MAF so you could get the airbox lid off properly and did you remember to plug it back in again afterwards? As that will throw up a fault code. Also the plugs need to be gapped correctly and tightened up correctly or they can cause the coil packs to pop off them although that generally gives constantly bad running, not an intermittent problem as you've described. Just some things to check really

I'll have a look in the Haynes manual and see if I can figure out which coloured wire is the one for the light dimming. If you take the dimmer control out (you'll need to remove the twist dial for the lights then unscrew the whole light control piece and take it out of the dash) and check the wires on the back of that I would've thought there will be one of a corresponding colour going into the multiplug at the back of the stereo.

Edited 1 August, 201015 yr by chicken_eyebrow

What Forge DV did you fit? Wasn't a split-R was it as they need adjusting properly otherwise they can cause a boost leak. There could also be a boost leak if the hoseclips weren't tightened right up when changing the DV. When you fitted the K&N did you unplug the MAF so you could get the airbox lid off properly and did you remember to plug it back in again afterwards? As that will throw up a fault code. Also the plugs need to be gapped correctly and tightened up correctly or they can cause the coil packs to pop off them although that generally gives constantly bad running, not an intermittent problem as you've described. Just some things to check really

What he said +1

Check all connections to the MAF. Also check that the coilpacks are fully home on the spark plugs.

Unplugging the battery will also reset the ECU and allow throttle body to reset so VAGCOM is not needed. Also you can remove fuse #5 (i think that is the right one) which will do the same, then re plug after 5 min.

I live in Havant Area, so close to Fareham if you need to borrow VAGCOM to error check and reset ECU check light.

okies thanks for all the replies chaps :0)

Things to do tomorrow:

I'll check all the coil packs are still secured on the plugs.

Check the maf connections are all tight.

Check Hoses to the Forge DV. (it was the standard Forge DV, not the spilt R, a friend fitted the split R and said he has loads of problems, so i avoided it)

I'll see if i can remove the dimmer form the dash and look for a similar coloured wire in the loom. (doh! didnt think of that lol)

Remove and clean the TB. Anyone know the part number of the Gasket? had a post bookmarked but cant find it now..... :0(

EDIT: "Throttle valve control unit gasket (1.8T engine) 028 129 748" <----- is this the right one?

So disconnecting the battery for 5 minutes is different from just disconnect for 2-3 mins?

Would be ace if i could use your VAGCOM Bowders1, would be nice to see if there is just 1 or more fault codes :0)

Thanks all,

Richie.

PS: does anyone know if the Octavia Mk2 tail lights fit the Mk1? they look much nicer :0)

Even if you disconnect the throttle body the car will still run a basic setting when you turn it back on - just leave the key turned for 30 seconds before ignition. It might take a few more drive cycles to get back to normal, but it will. FWIW you'll be able to clean it far more effectively if you disconnect it and take it indoors where the light's better.

okies thanks for all the replies chaps :0)

So disconnecting the battery for 5 minutes is different from just disconnect for 2-3 mins?

Would be ace if i could use your VAGCOM Bowders1, would be nice to see if there is just 1 or more fault codes :0)

PS: does anyone know if the Octavia Mk2 tail lights fit the Mk1? they look much nicer :0)

Disconnect battery just long enough for the ECU cycle reset to work a few minutes is all it needs. As mentioned all this does is speed up the learning process as after a few start ups and runs ECU will be back to normal anyway.

MK2 lights won't fit the MK1 as they as shaped different to fit the contours of the cars.

Edited 1 August, 201015 yr by Bowders1

According to Haynes the wire to the back of the OEM headunit that controls the backlight level is grey/blue, there is a corresponding wire coming from the light level control next to the light switch by the steering wheel.

If the head-unit you're fitting has a wire in the loom for backlight level then you might be able to splice one onto the other

According to Haynes the wire to the back of the OEM headunit that controls the backlight level is grey/blue, there is a corresponding wire coming from the light level control next to the light switch by the steering wheel.

If the head-unit you're fitting has a wire in the loom for backlight level then you might be able to splice one onto the other

Excellent thanks :0) i already know which wire is the dimmer on the alpine so i'll just hook em up and that should work fine..

Bit of an update also.....

Got the TB gasket on order should be here tomorrow, so i'll do that in the afternoon.

Checked all the coil packs and they all seem fine, looked at as many hoses as i could get to and couldnt find any that seemed to be damaged or loose.

However, this morning at 5:30 am i started the car up to go to work and it really really struggled to idle, was dropping as low as 450 revs then popping back to 1200 then back and forth.. Thought it was going to stall at any moment.

After about 2 minutes it all sorted it self out and drove to work flawlessly??

Did my days work and got into the car, started and idled fine, and drove home fine, parked on the drive and it was fine at about 750/800 rpm.

I had bought some electrical contact cleaner whilst out and about at work so i stripped down the MAF and cleaned it. Put it all back together and drove around a bit, idle and drive was fine. Went into a shop then came back to the car about 20 mins later, got in and drove home fine, i did give it a bit of welly on the way home, when i reversed onto the drive it started to struggle a bit to idle again, was dropping in revs then jumping back up to 800......

Gonna see what it does when i start it up tomorrow at 5:30 am again, then i have someone who is going to have a quick look at the codes with a Diagnostic device in the afternoon. Got it booked in for cam belt and water pump change so they said they would look at it for free to get the codes :0)

Edited 2 August, 201015 yr by RichieB75

If cleaning the throttle body doesn't help, change the coolant temp sensor as it is notorious for failing, & can cause bad idle. Make sure you get the revised VAG green CTS.

BTW do not force the throttle body butterfly open. After removing the throttle body rest something on the accelerator pedal with the ignition on or get someone to sit in the car & press the pedal fully down. It's then easy to clean thoroughly.

BTW, when you reinstall it turn the ignition on & you will hear the throttle body whistle for a about 30 secs or so, once it's stopped it's safe to start the engine. As already stated you don't need VAGCOM to do the adaptation as it will self adapt after a few days, but try to give it all throttle positions as this will help it to adapt properly

Edited 2 August, 201015 yr by pauldazzle

Meant to ask about the plugs, whay gap should they be, and can you actualy change the gap size of bosch super 4's?

If cleaning the throttle body doesn't help, change the coolant temp sensor as it is notorious for failing, & can cause bad idle. Make sure you get the revised VAG green CTS.

If they're changing the cambelt and water pump you might as well get them to change the coolant temp sensor at the same time as it's easier to put a new one in when there's no coolant in the system (the coolant leaks when you pull the old one out)

I think the gap size on the plugs should be .028 in

Edited 3 August, 201015 yr by chicken_eyebrow

So, bit of an update...

I took my Octy to the chap at the garage and he ran a diag:

1) Battery ground fault. - Disconnected the battery a few times so thats ok.

2) DV fault. - New Forge 007 so thats ok.

3) Coolant Temp Sensor fault. - Will come to that in a sec.

4) Throttle body fault. - He ran the doings and realigned the TB so thats ok.

After that it ran smooth and sits at 800 rpm fine, cold starts are ok now too. So all seems fixed.

Earlier i took the TB apart and cleaned it out:

TB Before

TB After

Runs smooth and all seems well :0) But.......

Took it out for a run and whilst out, I noticed that my temp needle on the dash is reading 0, as if the engine hadnt warmed up at all.

I know that when i get to a certain point not too far from home it is normally reading in the middle of the temp guage, which i presume is normal operating temp.

Hopefully, this is just a failed sensor, as the diagnostic picked up a temp sensor fault, do they normally just go like that? or fail over time?

The only that i have done since it worked is to remove and clean the TB housing, left it connected up and put a bag on the accelerator peddle.

Richie.

PS: it was indeed the blue / grey wire for the Head unit dimmer, got that working too :0)

Edited 4 August, 201015 yr by RichieB75

So, bit of an update...

I took my Octy to the chap at the garage and he ran a diag:

1) Battery ground fault. - Disconnected the battery a few times so thats ok.

2) DV fault. - New Forge 007 so thats ok.

3) Coolant Temp Sensor fault. - Will come to that in a sec.

4) Throttle body fault. - He ran the doings and realigned the TB so thats ok.

After that it ran smooth and sits at 800 rpm fine, cold starts are ok now too. So all seems fixed.

Earlier i took the TB apart and cleaned it out:

TB Before

TB After

Runs smooth and all seems well :0) But.......

Took it out for a run and whilst out, I noticed that my temp needle on the dash is reading 0, as if the engine hadnt warmed up at all.

I know that when i get to a certain point not too far from home it is normally reading in the middle of the temp guage, which i presume is normal operating temp.

Hopefully, this is just a failed sensor, as the diagnostic picked up a temp sensor fault, do they normally just go like that? or fail over time?

The only that i have done since it worked is to remove and clean the TB housing, left it connected up and put a bag on the accelerator peddle.

Richie.

PS: it was indeed the blue / grey wire for the Head unit dimmer, got that working too :0)

Stand corrected, prob the coolant temp sensor?!

Edited 4 August, 201015 yr by Malc

Coolant temp sensor. But they usually fail gradually, on mine it was never quite getting to 90 degrees for several months, then when the sensor really went t*ts up it kept saying the car was overheating when it wasn't!

They're about £28 genuine from Skoda or £5.91 from here (4 pin round plug). You need a clip and an O-ring as well. Takes about ten minutes to change.

Edited 4 August, 201015 yr by chicken_eyebrow

Buy a genuine VAG CTS. I bought one off ebay & all my gauges started to read low. Know a few other people who've made the same mistake with cheap ones.

ok cool, gonna pick one up tomorrow.

Just had to use the car to go and 'rescue' the other half from a flat batteyr and the temp sensor seemed to work this time.... tho moved between 80 and 90 randomely

The random movement of the gauge is a tell tail sign that the sensor is shot

Buy a genuine VAG CTS. I bought one off ebay & all my gauges started to read low. Know a few other people who've made the same mistake with cheap ones.

I'd recommend a genuine one as well. I bought one of those cheap ones off vwspares and it packed up within two days, took it to the local garage as I couldn't believe it was the temp sensor having only just changed it, but they said the one I'd bought wasn't moulded properly or something so wasn't seating right in the pipe. They put a £28 genuine VAG one in so that was a nice waste of £7 for me! However there's been at least one member recently bought one of the cheap ones and it's been fine... so you take your chances I spose.

woot no more management light :0)

Changed the CTS with a geniune one from Euro car parts, £24 plus they had the O ring and clip, which my local Skoda dealer didnt have in stock doh!

Buggered if i can find the hose thats got a small leak in it, chap who is doing the cam belt and map said he would root about and find it.

I also took the Bosch super 4's out and put the old PFR6Q's back in and it behaves better with the old plugs than it did with the new bosch ones in!!

The bloke who is doing my map also said to go and get some PFR7Q's as they run a bit colder, they seem to be OEM for Porsche Cayenne tho.... isnt that a bit overkill for plugs?

What do you rekon, go for the 7Q's or stick with the 6Q's?

Richie.