Much worse than digilag. Dangerous throttle delay

[Mr Blue]

Hi people.

I have a dangerous delay on the digifant. 8v PB
Its much worse than digilag thats for sure!

Ive double tripple checked the damn timing but im still getting this really long delay when i press the loud pedal.

I recently fitted a new head so the engine was in bits. Ive also got myself a CO2 meter and the MAF (allen screw) does not change the CO2 reading much.

When parked its fine when revved. It revs cleanly.
When i select 1st gear and try to take off I get a delay.

Also the brake pedal feels real solid but the brakes work.

This leads me to think its something to do with a vacum?
The servo pipes are firmly attached and ive double checked those.

Have I missed something here?

I did a search for digilag but this is much worse.
Anyone else had this problem?


thanks

blue

[Benrevs]

Does sound like the vacuum.  Have you got an induction kit fitted??  If so check you have the right hose going to the fuel pressure regulator and to the brakes..  tis all I can think of right now, Apart from timing!

[ToddyGTi]

Have you checked the microswitch on the TB? Could be that. You will also suffer this if the MAF is dead or with an induction kit fitted.

[Khare]

Does sound like the vacuum.  Have you got an induction kit fitted??  If so check you have the right hose going to the fuel pressure regulator and to the brakes..  tis all I can think of right now, Apart from timing!

dont think its timing, cos it revs fine when its idleing. I would say some sort of sensor is faulty. Or maybe the CO2 is wrong.

[Mr Blue]

Thanks all for the advice.

I managed to round the soft throttle body allen bolt    so couldnt test it with my new one.
So as a small test, I did connect the new throttle switch up and left my old throttle body in place and it didnt start. Im guessing im close to fault.

Ive got a K&N pannel filter in an undrill airbox. No performance mods.
Ive also changed the MAF for 3 others i had and did a CO2 test with no luck.

I checked the timing marks again so thats ruled out.

The brakes have been sorted. Used a heavy duty jubilee clip on the servo vacume hose.

Just popping out to get the throttle body off. Anyone seen my drill and sledge hammer?

[Mr Blue]

ok throttle body fitted. Its much better BUT i still get this digilag. It idles fine


Did a search but ive done / changed most things and cant work it out.

Any other tips? I was thinking fuel filter as i did run it low when testing the new head.

[rubjonny]

mine was just like this when i bought it, foot down nothing... nothing... nothing... argh I'm going to die!! ..boom some power.  was the ign timing at fault!  I take it you've done the old blue sender off and set ign to the diamond mark on flywheel @ 2.25k rpm right?

If so try it again, but keep the light pointed at the diamond when you connect the blue plug back up, it should advance nicely.  if not wiring to blue sender is busted, check you have 5v(iirc?) at the plug and the earth pin has continuity to earth.  Also worth checkin the knock sensor over, if it has any damaged insulation bin it and get another, pretty much  any 4 cyl vag lump one will work fine, I got one off a 2.0 8v audi, and the one fitted to my 2e block worked fine with the MK2 digi inj system.  Make sure nothing rattles in the engine bay as well, the knock sensor is right next to the alternator!

[Mr Blue]

mine was just like this when i bought it, foot down nothing... nothing... nothing... argh I'm going to die!! ..boom some power.  was the ign timing at fault!  I take it you've done the old blue sender off and set ign to the diamond mark on flywheel @ 2.25k rpm right?

Nice one jones. Ive done exactly that endless times. its always spot on.

Ill keep tinkering. Another quick one..

Does anyone have the digi vacume system diagram (hint to RJ) 

[rubjonny]

should be a piccy of it under the bonnet?

[Mr Blue]

Thanks for your help RJ

I double checked the timing marks after our little convo. The punch mark on the flywheel was correctly aligned too.

If i advance it by 20 degrees it runs soo smooth liek it used to.

Nock sensor fault or the just wrong torque me thinks


I also found this link. May come in handy for someone? Sticky worthy maybe?

http://volkswagen.msk.ru/engine/9a_pg_rv_pf_2h_92.pdf

If someone does a search...
8v digi timing mark, 16v timing mark. cam marks, tentioner, cylinder head, gasket, alignment, cam belt replacement


Blue