Hi all,

Just got in from work and my car seems to have developed a problem , only had it a few weeks !!

I put my foot down in 5th along the motorway and it normally holds 22psi but this time it got to just over 15psi and started juddering and missfiring and would not boost any higher, I backed off and tried it again but it did the same thing again. I pulled over and checked all the hoses etc but everything looked fine so off I drove again........when I put my foot down again it drove fine and held 22psi ! I tested it a few more times and every time it drove as normal !

What could have caused the juddering / missfiring etc... I thought it could be the Distributor cap and rotor arm ? (if these were on there way out could the missfiring etc be on and off ?) anyone any ideas ?

I also noticed that when the car was driving as normal (holding 22psi) the boost dropped off at high rpm, does everyone elses do this ?

Cheers, Duncan

 

by the way its had new plugs and leads recently, anyone ?

 

might be the plug gaps? over boosting?

mine drops off at high rpm to but im only running standard turbo, boost, chip, etc etc

IIRC my cousins S2 does tail off but only ever so slightly at top rpm...not by much though

bassboy

 

boost hose collapsing under load, maybe when it was heated up a bit softer????????

 

plug gaps are fine (C57's with a gap of 0.7mm). It wasn't overboosting cos it was only hitting about 15psi and then fcuking up rather than hitting 22psi as normal and holding. Distributor cap and rotor arm were the only things I could think of that could cause the problem and then be ok for a little while, anyone else ?

Duncan

 

problem solved I hope !!!!!!!!!!!!!!

It was the electronic dump valve controller being switched off ! This resulted in there being no pressure on the top half of the piston in the dump valve thus it was blowing open at about 15psi.

Duncan