S8 bad starting

[sapphire1616]

Hi All, I have a 2002 S8 and recently it has been a real pain to start from cold. Fine when up to temperature. The only way to start it from cold is to push the accelerator to the floor and it will eventually start with lots of smoke from the exhaust and really lumpy running, initially.

 

Is it something I can sort with my limited mechanical knowledge?

 

Thanks

[cruiser647]

You can reseat all the plugs, leads.  Also, if you can, plug in VAG-Com and check for errors to do with the cam position sensor and crank position sensor.

 

Might just be dirty?

[sapphire1616]

Thanks cruiser647, I can do the plugs and leads but the rest is a bit beyond me. May have to take it to someone for the rest.

[Cuprabob]

Sounds like a faulty temp sensor, especially as it it starts with plenty of throttle implying that the mixture is not being made richer for cold starting. Especially if the car starts and runs ok when at operating temperature.

[sapphire1616]

Where would I find the temperature sensor?

[Cuprabob]

Where would I find the temperature sensor?

I'm not familiar with the S8 but it will be a sensor located in the coolant path, normally in the engine block, with a 2-pin or a 3-pin plug.

 

This might help

 

http://forum.a8parts.co.uk/showthread.php?t=1157

[sapphire1616]

Thanks Cuprabob. I will have a look around to see if I can locate it. The article is really helpful. Thanks to all for responses

[sapphire1616]

Damn car won't start at all now, just fires a couple of times, so is there a way of fooling the sensor to get me mobile again.

[cruiser647]

Did you change the temp sensor?  On the V6 engines, the temp sensor is just in the V and even on my old V6 TDi I managed to change it.

So, might be in the same location on yours?  In the V, more on the driver's side, close to the front was where mine was.

 

 

Did you get VAG-Com onto read the codes?  Possible Crank sensor?

[sapphire1616]

I was going to drive down to get one today...guess the car thought otherwise. VAG-COM states temp sensor reading at -29c. Me in shirt sleeves, I think not. Anyway, I gave up and called the RAC man. Car now gone to local garage to have new sensor fitted. I am going to get one of these VAG-COM thingies. Are they expensive?

Thank you to all that responded to me in my hour of need. Most grateful guys.

[cruiser647]

You can get a basic Ross Tech VAG-Com thing on eBay for less than £100.

 

Be careful, as some of the cables are crap and some are cable only sales!!!

[sapphire1616]

Thanks cruiser647. Where does it connect in the car?

[cruiser647]

Thanks cruiser647. Where does it connect in the car?

 

Just above the pedals, below the steering wheel - about where your knee is.

 

 

[sapphire1616]

Thanks. Guess you can work out from my questions that I am not very technically savvy.

[cruiser647]

No probs on that score Mr!

 

I can do some stuff, but only because:-

1) watched the old man doing it on his car

2) too tight to pay a garage to do some stuff too.