Help with a disconnected connector on Throttle body (pic)

[Canters]

Hi All,

I have been wondering around here for a few days now trying to find the anwser to be question, but have not had any luck. Might just be because I don't know the right name for thing. Not got a Haynes book yet but XMas is only weeks away.

I have been having some problems with idling, stalling at the lights and very low revs at cold. I have cleaned the oil breather pipe, it was very very clogged up. I have also cleaned the throttle butterfly valve, I've also got some Carb Cleaner to give it more of a clean.

Upon doing this I found a connector that wasn't connected, so I connected it. Upon starting the car the revs sat at 2000 when idling, if I disconnected with the engine running the revs dropped to the normal 600ish. Connect it again and after a few seconds the revs go back up to 2000.

I have circled the connector in the below pic:


(Note I removed the cover of the back when working out what it was. The cover it normally on!)

What is telling the ECU to tell this to up the revs?

Thanks for any help,

Canters.

[spunkymonkey]

I could be wrong but connect the plug then disconect the battery. Reconnect it after 30mins then switch the ignition on and leave it for a few mins then try it again.

[boneybradley]

yeah try disconecting the battery for several minutes (as that will make the ecu loose its current settings and it will relearn new settings and hopefully will sort your issue out?)

[Paul86S2]

It looks the same size and shape as the connector on the lambda sensor. Could be wrong if there is another connector that shape.

Follow the lead and see what it connects to, if it is your lambda sensor it will connect into the exhaust somewyhere.

Paul

[leegt5]

That connector is not the same size as the lambda sensor plug !!

[Canters]

Hi All,

Thanks for the info. I have the car on the drive tonight in prep for a clean inside and out tomorrow. I'll disconnect the bat while I do it and try it again after that.

I'm I right in thinking that when it's plugged in and working it controls the rate the throttle is set back to idel from rev? and also acts as the choke?

Thanks again for the info. I will let you know the outcome tomorrow.

Canters.

[leegt5]

I'm I right in thinking that when it's plugged in and working it controls the rate the throttle is set back to idel from rev? and also acts as the choke?
Canters.

That is correct... My old throttle body was knackered and would cut out on cold mornings and would need me to hold the revs up to stop it cutting out.... Changed the throttle body and now when its cold it starts on the button and the revs stay up......

[Canters]

Hi All,

I disconnected the bat today for about 3 hours (got on with something else and got carried away ) When I connected it back up I turned the ignition on for two mins then started it. The rev's went right up to 2000 and sat there.

I had a thought and went hunting for my wife's Haynes book for her MK4 Polo. The engine is almost identical, I now have a name for the connector. It's the throttle potentionmeter.

With the name I have searched the forum again and have come up with a thread that seems to describe a similar issue, which was fixed by changing the crank sensor. I was going to see if I could use my mate's garage one evening and replace it as I guess it's never been replaced and the car's done 128k. Fingers crossed.

The other thing I am going to try is get it connected to a VagCom, but I need to find someone with one first.

If anyone else has any other ideas or things to try first please let me know as I would like to try and resolve this with out spending anything if poss.

Thanks for your help.

Canters.

[spunkymonkey]

Sounds like it was disconnected for a reason. Maybe a vacuum leak somewhere or the throttle body is just knackered. check round all the hoses for splits.

[AudiA8Quattro]

Can you not just replace the potentiometer? or is part of the throttle body?