timing mark question

**billygri77** · 06-03-2010,10:46 PM

hi friends,i have a mk3 1.6 8v with engine code AEK because i experience a hesitation on WOT between 2200-2800 rpm and have repalced almost everything i decided to check the timing marks between camshaft,distributor and crankshaft-flyweel but i cannot determine the flyweel mark.The mark i found i beleave is not the TDC mark but it is for firing.is this the TDC mark?
thanks

**Crasher** · 06-03-2010,11:37 PM

That is one of the two lugs for the VW timing display system which uses an inductive sensor, the mark you want for the valve timing is a rather indistinct cast in dot that is only clearly visible if you remove the green plug and you will need a 27-mm hex key for this or a bolt with a 27-mm head. When the crank is at zero, there is also a mark on the front pulley that aligns with an arrow on the plastic lower casing but this mark is not as accurate as the one on the flywheel. There may be another mark on the flywheel which is about 12-mm away from the dot but still between the two big lugs and this is more of a diamond shape and more distinct, this is the stroboscopic timing mark to be used with a timing light to set the ignition timing but this is not used on the AEK, all you need to do is ensure that the dead centre of the rotor arm aligns with a notch on the thin top edge of the distributor body when the cam and crank are set at TDC.

**billygri77** · 07-03-2010,12:13 AM

so this is not the TDC mark?i checked that when the camshaft pulley is on the OT mark the distributor is at No1 cylinder but i have not check the crankshaft because i am not sure for the mark on the crankshaft pulley is alligned with the plastic arrow.I also notice that the rotor shaft of the distributor has a little free play,is it normal?
thanks

**billygri77** · 07-03-2010,03:07 PM

Originally Posted by Crasher

That is one of the two lugs for the VW timing display system which uses an inductive sensor, the mark you want for the valve timing is a rather indistinct cast in dot that is only clearly visible if you remove the green plug and you will need a 27-mm hex key for this or a bolt with a 27-mm head. When the crank is at zero, there is also a mark on the front pulley that aligns with an arrow on the plastic lower casing but this mark is not as accurate as the one on the flywheel. There may be another mark on the flywheel which is about 12-mm away from the dot but still between the two big lugs and this is more of a diamond shape and more distinct, this is the stroboscopic timing mark to be used with a timing light to set the ignition timing but this is not used on the AEK, all you need to do is ensure that the dead centre of the rotor arm aligns with a notch on the thin top edge of the distributor body when the cam and crank are set at TDC.

ok i just removed the plastic 27mm female plug and found that i am ok on the TDC where is a line on the flywheel then i am ok on the OT mark on camshaft and ok on the distributor rotor,timing is ok.Thank you very much for the help.I stil cannot find solution for the hesitation on WOT on low rpms,any help will be much appreciated.

**Crasher** · 07-03-2010,03:46 PM

No, as I said, that is not the TDC mark it is one of the two inductive timing sender pegs and of no use to you, the TDC mark is a small cast in dot in between the two inductive timing pegs. Free play in the distributor is correct.

**Crasher** · 07-03-2010,04:09 PM

Get a fault code read done.

**billygri77** · 07-03-2010,04:23 PM

when the OT on camshaft sprocket,the deep line in the crankshaft auxilliary pulley and the distributor are alligned i can see on the flywheel a deep line alligned with the housing and it can be seen as you said me when the plastic hex cap is fully removed,do you know if this line on the flyweel is the TDC?
I have scanned for codes with vag com and do not have faults

**billygri77** · 07-03-2010,04:25 PM

Originally Posted by Crasher

No, as I said, that is not the TDC mark it is one of the two inductive timing sender pegs and of no use to you, the TDC mark is a small cast in dot in between the two inductive timing pegs. Free play in the distributor is correct.

it has an inductive speed sensor near the oil filter on the transmission bellhousing so i beleave this is for triggering the speed(crankshaft sensor) then.

**Crasher** · 07-03-2010,08:55 PM

The sensor in the block is the crank speed sensor (G28) which provides the ECU with engine speed info for ignition timing, the sensor in the distributor (G40) tells the ECU where number 1 cylinder is so the ECU can provide sequential injection and the spark is distributed in the time honoured way. The mark on the flywheel can be a line and if that line coincides with the mark on the front pulley aligning with the arrow on the timing belt cover, then the engine is at TDC 1&3, if the OT mark aligns with the arrow, then the engine is at TDC number 1.

**billygri77** · 07-03-2010,10:06 PM

Ok your info is very detailed and thank you very much.I checked and i am on marks so timing is correct.
I dont know if the timing belt is low on tension and that is dangerous because i can pull the belt from the crankshaft pulley with strenghth of course is it normal?I also cannot find solution for the hesitation,is there any possibility to hesitate from the ISV?(idle stabilization valve).
thanks