help S in pain

[vodkakid]

help my cars not right and im not sure what it is. symtoms of its pain are while im driving i can feel my car resisting my right foot and it doesnt want to go then it will change its mind.
next symtom when slowing down or coming to a stop and idleing it hunts and some times it hunts so much the battery light comes on (as in start up). now its start to cut out all together when i stop then runs rough???!!!
ive just got a new battery and ht leads ive checked as much as i know of the alternator, coil(soon to replace plugs) any ideas out there or is it something to do with the ecu meaning going to a dealer. if anyone out there can help theres a beer in it for you(sorry thats a lie but i will be very happy)

andy c

[vodkakid]

Just read what I wrote last night hope it makes sense, it had been a long bad day . On the plus side i think it may be the throttle pot in some shape or form, I cleaned the connectors last night and in seemed ok on the way in to work (real test the ride home)

andy c

[johno]

If you take the throttle pot oput of the system the car should run fine and not hunt. The idle will be higher. Start the car with the pot in place and then remove the moulded connector and see how the engine revs chsnge. That should identify whether you have an issue with it.

It does sound like an issue with the throttle pot.

Cheers

Mark

[hardinta]

My S3 started doing this a while ago. The solution lies in cleaning the sponge air filters and in cleaning the sometimes dirty contacts on the throttle mechanism at the front of the intake system.

Hope this helps.

Toby.

[vodkakid]

what should i clean the air filter with?

andy c

[philtvr]

You can but soloution from boy recer places. Remeber to rinse from the inside out or the cr*p will get pushed into the air filter!

[tvrmark]

quote:
If you take the throttle pot oput of the system the car should run fine and not hunt. The idle will be higher. Start the car with the pot in place and then remove the moulded connector and see how the engine revs chsnge. That should identify whether you have an issue with it.

It does sound like an issue with the throttle pot.

Cheers

Mark

It does sound like the throttle pot but unplugging it will not prove anything. If you unplug any part of the engine management system (throttle pot, water temp senor, charge temp sensor etc)the ECU puts itself in limp home mode. eg raise the revs to around 1500 and disregards its sensor inputs.

Another Mark

Edited by tvrmark on Wednesday 28th November 22:03

[JSG]

Andy,

If you decide to change the throttle pot, check the threads on the S forum first - there's a lot of good info about making sure you get the correct one.

Cheers

[johno]

quote:

quote:
If you take the throttle pot oput of the system the car should run fine and not hunt. The idle will be higher. Start the car with the pot in place and then remove the moulded connector and see how the engine revs chsnge. That should identify whether you have an issue with it.

It does sound like an issue with the throttle pot.

Cheers

Mark

It does sound like the throttle pot but unplugging it will not prove anything. If you unplug any part of the engine management system (throttle pot, water temp senor, charge temp sensor etc)the ECU puts itself in limp home mode. eg raise the revs to around 1500 and disregards its sensor inputs.

Another Mark

Edited by tvrmark on Wednesday 28th November 22:03

This may be the case, but this is how I proved I had an issue with the throttle pot and also how I managed to get home when it had gone tits up.

Its alright saying the ECU will switch itself into limp home mode but unless you have a testing diag unit to go through all these sensors or want to hand it over to a garage every time then you need to check things the traditional method.

Secondly, if it isn't the throttle pot and a more fundamental problem then whether the ECU goes onto limp or not it won't make any difference. If the engine don't work then the engine don't work. Therefor removing the plug will indicate the level of the problem.

When I am completely stumped (hole in the brake servo for instance - giving similar symptoms to those described) removing the plugs to several sensors made no difference to the problem and therefor I knew I had a more significant issue and went looking for it. It has saved me a significant amount of money.

Cheers

Mark

[johno]

Just to be add some more controversial comments to this one.....

I use the throttle pot from the S6 Cerberra at the moment without any issue at all. Something WLA's and I tried with success.

They are also a 1/3rd cheaper than the Ford replacements item.

Cheers

Mark

[vodkakid]

i cleand the contacts the other night and it seems better not 100% but better im in treasted in the cerb idea is it a staight fit, plus i need to check my brakes because they felt different on the way home (to many things to check not enough time)ie hole in brake servo

andy c

[vodkakid]

p.s what the hell is in treasted????
great typing

andy c