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Think i have found why Audi V6 won't start
trogdor - 26/2/09 at 07:38 PM

Hi everyone,

further to recent posts I have been trying to start an Audi 2.6 V6, it has sparks and fuel and there are no fault codes logged in the ECU

however when i line the cams and crank up, piston no 3 is supposed to be at TDC however when no 3 is at TDC the indicator on the crank is about 35 degrees before where is suppposed to be. I wouldn't expected it to completely accurate but 35 degrees is a bit much?

I don't suppose anyone has the two locking tools i need?

Do you think that the engine will be damaged?

I think the tensioner has slowly failed and the belt is slowly slipping. This would tie in with the sellers story of it getting harder and harder to start and run.


Paul TigerB6 - 26/2/09 at 07:41 PM

ouch - time for a new tensioner and belt then hey. Can you turn the engine over by hand then?? Hopefully you can and havent bent a valve or something


trogdor - 26/2/09 at 07:47 PM

yeah it turns over fine, by hand and by starter unfortunaly its been turned over by starter loads.

would like to do a compression test to see if the valves are bent but i guess i better replace the belt and tensioner first tho.


adithorp - 26/2/09 at 08:17 PM

Check the key on the bottom pulley. They've been known to shear. Also the cam pullies can rotate on the taper if not done up tight enough but thats unlikely if the 2 cams are timed the same.

adrian


rusty nuts - 26/2/09 at 08:25 PM

IIRC there are possibly two V6 timing tool sets ? If you know the engine code it should be possible to identify which tool you need. If you can't see it on the engine have a look in the boot , there should be a sticker with a load of info on it .


trogdor - 27/2/09 at 09:52 AM

Hi thanks for letting me know about the tools, will probally make my own to lock the crank and its not so important for the cams.

The belt was only put on in 2007 with a water pump and it looks in good condition so won't replace it for now as am not gonna be using the engine for awhile. Will replace the belt etc when i fit the engine into my project.


Schrodinger - 27/2/09 at 12:28 PM

If the piston and the crank markers are out it must be the crank pulley that has slipped not the timing belt what about the other cylinders? Don't you normally line up cylinder 1 with the TDC mark not 3?


trogdor - 27/2/09 at 01:17 PM

I have been told its TDC on No 3 by people on a audi forum. And when the crank and cams are lined up its offset from TDC by 30 degrees. I think the pulley has slipped and someone has timed it in by just using the marks on the front of the engine.

I had thought the the tensioner was failing and allowing the belt to slip but it seems fine. Will be resetting the timing soon and will see if it works.

Could do with a crank locking tool tho, hoping to borrow one or make up something that will work.