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mattpolog40

Still have polo g40 timing issue

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mattpolog40

Had a timing issue for a good few months now and it's been driving me up the wall.and I think I've now worked out what the problem is but not quite sure how to rectify it.ive noticed the rotary arm is sitting at the 4 o clock position when set to tdc rather than 10 o clock like it's supposed to be so im now unsure of how to like it back up so it's back in the right position.does anyone have any ideas ive tried everything possible and I'm running out of ideas so if anyone can help please feel free as I really want my g40 back on the road thanks as always matt 

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kiran_182

Take the dizzy off rotate the cam with belt still fitted  till it is on tdc and the dizzy location hole is in the right place and  refit the dizzy

 

There are 2 marks on the lower pulley, are they both near the marker or are they ofset to one side

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mattpolog40

I've done that and still end up with the same result it still ends up back at the 4 o clock position 

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steveo3002

post some pictures of the timing marks for us

 

time it all up with number 1 piston at the top and photo the crank and cam pulleys 

 

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mattpolog40

Will do just heading out now 

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mattpolog40

Think I've cracked it on the four revolutions for everytime it hits a cylinder whilst turning the cam pulley its set nicely to tdc but it's seems quite a few teeth out from the timing mark on the cam pulley which worries me.trying to get pics but it's rained 5 times so keep having to pack up but I think I've made a breakthrough I've found the 10 o clock position the rotary arm needs to sit at but the timing mark being off worries me 

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mattpolog40

Both timing marks are set perfectly and and it's sitting and tdc however I still have a herendous misfire making it impossible to set the timing to the mechanical timing mark with a timing light 

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dvderlm

Do you see sparks from a spare plug put into each lead?

 

Hall sender in the distributor working?

Haynes describes testing the sender with a voltmeter.

 

You should be able to attach probes to centre and negative on the three pin connector, loosen distributor bolts and rotate by hand with everything at TDC, to find change from 0 volts to more than 2 volts. Mark that transition point at dizzy body with permanent pen.

Then turn dizzy  bit by bit (opposite to spin of rotor arm) about 2.4mm at circumference from the mark. That should be 5 degrees static before TDC.

 

The ECU will add 5 degrees with engine cold to give 10BTDC. That will start most internal combustion engines.

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mattpolog40

Hall sender is working you can hear it click and open injections so I know that's working not checked leads yet as I'm a one man team is it a one man job without sounding thick?

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mattpolog40

When it's set to tdc it's a bugger to start and when it does start it runs lumpy as hell and cuts out and splutters and all sorts of doesn't sound healthy at all but it's set perfectly 

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dvderlm
14 hours ago, mattpolog40 said:

Hall sender is working you can hear it click and open injections so

So if you disconnect the 3 pin plug how does it sound?

14 hours ago, mattpolog40 said:

When it's set to tdc it's a bugger to start

At 0 degrees advance the spark is way too late. The flame needs to travel with the cylinder's descent.

Starting needs about total 10 at about 250rpm.  The ECU ignition control circuit sets this and varies according to manifold pressure. 

 

On Vw combustion engine it usually needs to be set between 4 and 6 degrees before TDC at idle - where exactly is engine and fuel specific.

That's a very tiny amount of correct space for possible movement 2/360th is 1/180th of the circle. 

 

 

Checking plugs are all sparking the same is much easier with two people.

You could look at sparks your self in dusk light or put the spare plug in a metal pipe with jump lead to negative battery so that you can look down the pipe from driver's seat.

 

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mattpolog40

Thank you I will grab some help today and check for a spark then because this has been going on for to long now 

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mattpolog40

At this moment it's set to the z mark as I've not got as far as moving it to the 0 mark with the strobe light as it won't run stable enough sadly 

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dvderlm

You've got it running with timing light showing still crank pulley line marker at Z (for Zündung = ignition). The Z is the 5 degree mark for that pulley.

That sounds fine, there's sparks and fuel.

 

Does the timing mark wander about?

Might not be all cylinders firing equally.

 

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kiran_182

Also the keyway on the crank pulley can wear and allow for movement 

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mattpolog40

Yes the timing mark jumps about quite abit whilst looking at it 

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dvderlm

Camshaft has a key too. But yeah, crank pulley is worth checking, now you know how to set TDC.

Have you removed timing belt before?

 

Easier than looking at sparks. If it will ide for long enough, hold a piece of paper against the exhaust pipe. It should get regular pushes away. if it is sucked onto the pipe it's a misfire.

 

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kiran_182

As said before though low compression can also cause the same wobble 

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dvderlm

That was meant to be :-( not Like.

Paper on exhaust will highlight one poor cylinder if you have good rhythm. 

Mate of mine records the engine sound then looks at it in Audacity or another wave-form software where you can zoom time.

 

Buy a good compression tester. I had a shite one to begin with and it lied. Can't remember who made it but there's probably a post on here with me whinging about it.

 

 

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mattpolog40

I think it's a misfire as it sounds like a Subaru and won't rev past 3000 without sounding like a typical misfire.ive put an sos out on Facebook to borrow a compression tester so will let you know my findings 

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mattpolog40

Sorry about the bad pictures 

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dvderlm

Looks like it's all at TDC. So just rotate the dizzy clockwise a fraction. Maybe half the width of the metal centre part of Hall sender.

 

5/360 ths of the crown diameter divided by two because the camshaft moves at half engine speed.

 

Have you tried the paper on exhaust outlet at idle? Not being able to rev can be collapsed catalytic convertor (and plays havoc with airflow).

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steveo3002

id try twisting the dizzy once its running see if it sounds better in any direction

 

and just checking...the photos are with number 1 piston at the top right?

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