UK-POLOS.NET - THE VW Polo Forum

Hi all, I wonder if anyone could help and shed some light on an over revving problem.
I have a 1997 Polo 6N 1.4CL AEX engine. Despite my loation, it's a RHD UK car.
i have searched this excellent forum but dont seem to be able to find a definitive answer.
Had a misfire, went to running on 3 cylinders, changed Distr.cap, rotor arm and plugs. still the same.
My local supplier had to order the leads. Whilst waiting for the leads to arrive and after reading info on here, I decided to clean the throttle body. i didn't take it off. I cleaned it with cleaner and cotton buds, holding the butterfly open. It wasn't too dirty just a bit of carbon build up around the edges of the butterfly. Started the engine, still running on 3 cylinders but now idling at 1500 - 2000 revs.
Fitted the new leads today, now running on 4 cylinders perfectly but still idling at same revs. Drove the car and still over revving between gear changes or when stopping at a junction.
I have tried unplugging the temp sender (I have 2, one green, one red. the green one is the one that is for the temp gauge in the car)
When I turn on the ignition, the VDO unit on the back of the TB whirrs and hums and then the butterfly moves a fraction.

I can only assume that the cleaning of the throttle body has caused the fast idle.
Do I have to have the TB re-set to the ECU even though I haven't removed it ?
Is there another way of doing this without going to a vw stealer?
is there another solution?
I have tried to include as much info as possible but sorry if it's a bore.
thanks for your time.
Jezza

Its gonna be an ECU reset to clear the throttle body problem. Its happened to me in the past (the same!)

You can try disconnecting the battery for about 2 hours then reconnecting to see if it will align it that way, otherwise you will need a copy of vag com, know someone who has it, or visit a workshop to get them to realign it for you

The slightest touch on the butterfly valve will send it out of alignment - even if its like 0.5 degrees out, itll lead to problems

Hope this helps!

Alex

Thanks for your reply Alex. I shall try that.
J.

Ok, I tried the battery disconnection but it is still the same.
If I continue to use the car as it is, will it cause any problems?
This will be for a few days until I can get it to a workshop.

It wont, but it will increase fuel consumption etc.

Ok Alex, thanks again.

Another quick question, hopefully someone will know.
I have located a garage which has a Bosch ESI tronic diagnostic system.
Does anyone know if this system is capable of resetting my Throttle Body via the ECU as per Vagcom?
I have searched online but can't find a definitive answer.
The garage owner is not certain as he has never had to do this on a Polo before and also, this garage is about 50 k's from me and I dont really want a 100k round trip for nothing.
I am trying to avoid our local VW stealer as they are not great !

Thanks
J.

Im not sure to be honest- its a vag com thing

could get yourself a cable off ebay and do it yourself

Do I not need a vagcom system then? Just a cable? Excuse my ignorance.

Get an ODB II cable off ebay, and download vag com for free from www.ross-tech.com

Let me know when you get it, and ill guide you through resetting the TB

Sorry to be any trouble or to sound thick but there doesn't seem to be a free download.

Ok, I still have problems but we are a little further forward.
An English run garage reasonably local to me kindly offered to re-set the throttle body FOC, this offer came on the same day that a Spanish neighbour had recommended a garage in my town who quoted me 35 euros "just to put the machine (vagcom) on the car" any other operations would be extra !
So, today I took the English guy up on his offer and made the 45 min trip to his place.
He has a Bosch ESi tronic diagnostic system which does much the same as vagcom.
I had a couple of fault codes. Temp sensor and Idle control potentionometer valve.
He cleared the fault codes and re-set the throttle body. On starting, the car idled at 1200rpm, bearing in mind that it's usual trick was to sit at 1500 to 2000 rpm.
So, it was better but not right. He exited the system and did another scan which showed the idle control valve as a fault code again (the temp sensor fault code did not re-appear). He came out and went back in again and the ICV fault code didn't re-appear.
Due to a couple of delays with the system, this being a freebie and the guy being very busy with Sat morning walk-in customers, he had to stop. He wants to have another go with the system to see if he can re-set the idle values.
On driving the car, I still have an idle problem and the revs still rise up to 2000 rpm between gear changes or when coming to a junction. What is different though is that, whilst driving, the revs feel like they want to drop to normal more often so the "cruise control" effect of 30 mph driving with my foot off the accelerator is greatly reduced.

I have a few questions to ask and wondered if anyone here has experienced similar.

Is it coincidental that the idle control valve should play up after I cleaned the TB butterfly ?
Could it now just be a matter of re-setting the idle values ?
Is the I C V repairable/cleanable if it is faulty or dirty ?
If not, are they expensive to replace?

Thanks again for taking the time to read my ramblings.

Hi again
I still haven't managed to fix this problem as since my last post we have had visitors, been away to France and I have been unwell (still am to a certain degree). Anyway, I am waiting delivery of an ODB II cable but in the meantime, can anyone answer my queries from my last post please? Alex maybe?

Many thanks
J.

Is it coincidental that the idle control valve should play up after I cleaned the TB butterfly ?
Could it now just be a matter of re-setting the idle values ?
Is the I C V repairable/cleanable if it is faulty or dirty ?
If not, are they expensive to replace?

ICV can play up after cleaning the throttle body

Yes it could - a recalibration could fix it

The ICV is an integrated part of the throttle body...unfortunately it cant be removed or replaced individually.

A new one is expensive so a scrapyard sourced part would be preferable

Hope you get better soon J

Wow, thanks for the quick response Alex, much appreciated.
I have a copy of the free Vagcom and the Ross-Tech how to guide. Once I receive the cable I shall have a go.
I'll let you know how I get on.

Thanks again.

J.