boost problems/ hessitance

[avants2turbo]

Im haveing some issues with the car when on boost, it seems to spool up ok but sometimes (3 outa 4 times) it doesnt boost smoothly, it like hesitates several times, with some like violant jerking...

any ideas?

[A80Avant]

does it do it just before you go into wot,or when you are into wot?

[avants2turbo]

definately does it at WOT dont think it does it when its boosting off WOT, not sure if it starts just before WOT....

[popdemonic]

check if the boost is leak.You'd better suspect the iginition(coils ,plug boots ,spark plugs,POSs) system next

[RoadKill]

sounds like a coil pack , same thing on my 100 S4 i had

[wilywyg]

I just had the same and it was one of the POS , only on high boost 2.7k-3.5k revs
changed mine for a 2.6 one and its sound , so the lads here said it would be.and i will take the cover off it to find out why!


paul

[avants2turbo]

I just had the same and it was one of the POS , only on high boost 2.7k-3.5k revs
changed mine for a 2.6 one and its sound , so the lads here said it would be.and i will take the cover off it to find out why!


paul

whats POS?

still doing this....

[Flat on my back]

.

Power
Output
Stage...also known as...

Pile
'O'
Sheite...

Each of the COP's needs a high power driver to 'fire' it.

[avants2turbo]

whats POS?

still doing this....

Ah POS = Power Output Stage

do I still have this, ive got the apikol coil kit....

https://www.apikol.com/#Products,Engine,21

i dont think mine uses the POS, it seems to have it built in... what should i check/how do i check it....

thanks

[merlin's S4]

Ah POS = Power Output Stage

do I still have this, ive got the apikol coil kit....

https://www.apikol.com/#Products,Engine,21

i dont think mine uses the POS, it seems to have it built in... what should i check/how do i check it....

thanks

Correct, the 1.8t coilpacks, as used with the apikol kit, have built in amplifiers (POS). In my experience these coilpacks just fail completely leaving you running on 4 cylinders. They don't seem to give intermittant misses! I would look for a boost leak!

[EspenW]

Check plugs and check resistance of the plug connectors (sits between plugs and coils)

[avants2turbo]

Check plugs and check resistance of the plug connectors (sits between plugs and coils)

how do i do this.. electrics isnt my forte....

[merlin's S4]

how do i do this.. electrics isnt my forte....

Again that assumes you have standard coilpacks. You can check your plugs are in good condition and also make sure they're torqued down properly. I would check for boost leaks first!

[avants2turbo]

Again that assumes you have standard coilpacks. You can check your plugs are in good condition and also make sure they're torqued down properly. I would check for boost leaks first!

I had a boost leak test done a while ago, and when the hessitancy isnt there it feels as strong as it ever has, and I dont have standard coils, I have the Apikol kit which uses the A4 coils, modified with built in POS (see link in one of my previous posts above)

[UrS4boy]

Im haveing some issues with the car when on boost, it seems to spool up ok but sometimes (3 outa 4 times) it doesnt boost smoothly, it like hesitates several times, with some like violant jerking... any ideas?

If you have checked your plugs and a boost leak test came up with nothing either you have a Waste gate spring that is too stiff (1.9 bar) or it is screwed down too tight (especially with the 1.9 bar spring) OR....you have a dead/dying 1.8t coil pack. At idle, pull the injectors one by one to see which cylinder least affects the smoothness of the idle (that will be your suspect coil pack). I had a weak 1.8t coil pack that survived for several months and only caused a problem at WOT sometimes. Finally it just flat out died. Much easier to find (injector trick above) and replace (note that the hard plastic and some of the rubber ring need to be trimmed on the replacement coil pack - use the dead coil pack as a template).