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Discussion Starter #1
I've spent hours on this forum looking at ignition timing threads. I've had more Golfs and Jettas of all Marks than I care to remember so I've looked through the Golf Mk2 and Mk3 Haynes workshop manuals and I've looked on Google, Club GTi, Vortex etc, but I don't seem to have the same set-up as everyone else.

I have a 2L AAC, 1st registered November 94 on an M plate. It's got Digifant EMU with Catalyst. I only have one mark on my flywheel, the diamond shaped one, no circle for TDC that I can see. The van runs and ticks over pretty well, but I can't help feeling it could hold it's power better on hills and give slightly better MPG (I get around 22mpg).

I've checked the ignition timing with a non advancing xenon timing light (an old Draper), at 2250rpm with the temp sensor disconnected there is no sign of the timing mark in the Bell housing window. Moving the distributor both ways just makes it run rough but doesn't bring the mark into the window. The distributor's rotor arm lines up with the notch in the body at #1 TDC, but there does seem to be a lack of timing marks compared to my old Golfs.
My questions are:

1. Is the diamond shaped mark in the cut out in the flywheel TDC or a ignition timing mark (6deg BTDC)?
2. Should there be a 'O' for TDC as with Golf, I had that on my Mk3 ADZ engine?
3. Do I need an advance timing light to do this properly?
4. With the Temp sensor disconnected it's a bitch to rev to 2250, but starts okay - is this normal?
5. Is there a decent workshop manual available for the T4 I don't know about, Is ERWIN any good?

I've been using this site a fair bit, but somethings not the same between my van and his descriptions. I'm starting to wonder if the cam belt change was done right last time: http://fuelie.tripod.com/tuneup.htm

Any help would be much appreciated.
 

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I have a 2.0l petrol 1993 non-cat. I have set up the ignition timing without any problems a few times (after changing dissy etc). Looking at the flywheel thru the inspection hole and rotating the engine forward I see a line (timing point) and shortly after a 0 which marks TDC. I highlight the line (timing mark) with a white mark. The engine must be hot and when the cooling fans have cut in (indicating operating temp) I then remove the temp sender plug and check with stobe light at 2000 - 2500 rpm (with rev counter), should be 6 degrees plus/minus 1 degree. Adjust by rotation of the dissy if not correct. Once set, check again at exactly 2200 rpm with temp sender re-connected, the timing should now be 20 degrees more advanced, if not there is a problem with temp sender of digifant control.

If the engine is starting and running well I would suggest all is well as these engines do not like it when timing is even a little out. I would take another look at your flywheel to check for the timing marks (should be there), re-check the static timing by satisfying yourself that the rotor arm is pointing to the dissy mark with number one cyclinder at TDC. I think that if you had a problem with anything as you mention, the engine would not start and run well. There is no decent manual available, but the timing procedure is quite straightforward. Your mpg of 22 is not unusual, I only get this sort of figure on short/town driving and only get a more reasonable mpg on decent longer runs. Power wise, yeah this is not a high performing lump, just have to live with it. Hope this is of some help.
 

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Discussion Starter #3
Thanks for the reply Phot,

Don't get me wrong, I don't expect to be smokin' Porsche's off at the lights. The running is pretty good and I think it does well for 2200kg unladen, I just would like it set it up perfect really, get every lb/ft of torque it should have.

I've rechecked the timing the flywheel, I cannot see anything other than the one diamond shaped mark. I cannot see any 'O' shaped TDC marks.

When you say to "set the timing to 6 deg +-1", do you have an advancing timing light and dial in 6 deg and look for the TDC mark, or timing mark? Or do you use no advance on the timing light and point it at the line (or diamond as I call it)?
I've also rechecked the distributor alignment, with the diamond on the flywheel lined up with the pointer, the rotor arm is just to one side of the distributor #1 mark.

I'm quite and advocate of 'if it's not broke don't try to fix it', it's not the biggest problem I have with the van, but it is niggling me I cannot see the correct timing with the strobe light.
 

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That is quite odd that you can only see a single diamond shaped mark on the flywheel. The "book" suggests you will see a line for the advance position and a 0 or 0T for TDC. I use a simple strobe, nothing with dial in etc. If there is really only a single mark on the flywheel, I suppose that would be TDC? (does that look right when number one cylider is at top and dissy/rotor arm correct?). When I replaced my distributor, I initially only set the timing by positioning the distributor, but had difficulty starting/running. It was only when I went back to basics and fully checked it with the stobe in the method I have described that I achieved good running. It the diamond mark on your flywheel is TDC, I could measure the distance of the 6 degree mark on my flywheel forward of the TDC mark so you could reproduce on yours. I doubt that a degree or two in the advance would have any significant effect on running.
 
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