High boost misfire when (really) hot

[Ian Simmonds]

Our S2's (ABY Estate - MTM remap) picked up an odd habit. It's fine and boosts beautifully most of the time. But when I take it on long motorway runs and the heat builds up under the bonnet it picks up a high boost pressure 'hesitation'.

Any idea's what's going on?

I was thinking maybe coil packs or similar... Any thoughts?

It's pointless taking it to a garage as it takes about 80 miles at (70ish:mischeif: ) to get the problem to occur.

Thanks in advance

Ian

[Jon441cc]

Ive got a perfectly good coilpack collecting dust in the garage if your interested, a £10to cover postage and its yours.

[Ian Simmonds]

That'd be brilliant Jon, I know nothing's guarenteed with cars electric's, but do you think it's a possibility?

[Jon441cc]

POSs could be another possibility, but with these sort of things its always best to go with the cheapest option first.
Have you been able to check coilpack boots?

[merlin's S4]

If it's definately heat related then I would suspect a POS.

[Ian Simmonds]

No Jon, I haven't, the old girl's had to work quite hard lately and although she get's everything she needs (garage bill wise) this little fault draws a blank as there are no codes showing and (as far as they can see) no problem... It's only after a long and hot run. To give you a clue, today, it started showing up abound Banbury on the M40 from all the way up off the south coast. Got stuck in traffic on the M6 toll and shut her down for 10 minutes (awaiting plod/brigade etc to clear wreckage ahead) and it'd cleared when I floored it away from the M6 Toll booths.

So I'm guessing something's breaking down with the high temperatures.

Sorry, being blonde here, POS?.

[Ian Simmonds]

Power output stages, right got that..

[Jon441cc]

POSs break down due to high temps, Coilpacks break down at high boost levels, so id have to agree with merlin on this one.
I know that those POSs are little sods to replace though, but if you are gonna replace them make sure that a heat paste is applied to the back of the plate which the POSs are attached too, so that when they do start to warm up the heat is dissipated.

[Ian Simmonds]

If I can Jon, I'll check the coil packs/boots etc when I get back home Wednesday and depending on what I find, may well be in contact for the Coil Packs. I'll have a poke about, but nothing major as I need the old girl for a fortnights work starting Sunday.

Any idea what a new set of 'POS's are worth and are they any easier to change if bought from VAG?

[Jon441cc]

Dont quote me but i think there £39 plus vat each.
Im sure Vag can sort you out but whether buying from them will make changing them any easier i doubt it.
There are two nuts and bolts on each POS which secure them to a plate and with it being so cramped at the back of the engine bay it can be awkward to get to those nuts at the back of the plate.
Hope this helps.

[Ian Simmonds]

Thanks for all of your help Jon, I'll need to 'identify' the bits under the bonnet - then decide whether to have a bash. If it's just a knuckle skinning (parts swap) job with a socket set/spanners and electrical plug's then I'm probably okay. But when it involves rebuilding half the car, I'm not. - I'll get the bit's priced up with my local 'beer-drinking' Audi Parts Manager.