lukewhite

Hi I have recently bought a rs mk1 and it's developed a misfire when under load when I put my foot down hits boost and won't rev past 3k anyone got any ideas what it could be ?

Thanks luke

martysmartie

iTrader: (1)

Look toward the ignition system first, i.e. plugs and leads.

Martin

lowman

actually i think you should check the mass air sensor..
especially the wires for it.

can you ease the rev to max...if you are beeing gentle..and just when the car sits still?

lukewhite

ye the car drives fine if i drive normally just wont rev past 3k. And if i rev sitting still think it seems to be ok not really noticed

lowman

hm...could sound like either the mass airflow sensor...located on the inlet on the turbo,,check the wires that they are not corroded ,and in worst case ripped of...if they are fine..it could still be the mass airflow sensor itself.you have to get a diagnostic to see what values it reads out on that sensor.

or mentioned before...the spark plugs ,leads or ignition coil,check for resistance in the leads,has the car gotten the spark plugs changed recently or not?

lukewhite

ok thanks Il check the resistance and in going to get a fuel pressure tester. I have plugged it in and its come up with wastegate solinoid but it hasn't got one its been taken off

lukewhite

and no plugs have not been changed but would it really cause this problem just the plugs and leads ?

martysmartie

iTrader: (1)

Yes it most certainly can, especially in a FI engine when the cylinder pressure increases!

Martin

lukewhite

can a fuel pump and fuel regulator cause this problem ? I believe that have a common fault in in tank fuel pumps as my previous st170 has a fault ?

martysmartie

iTrader: (1)

Well you need to verify the ignition system is ok, before looking elsewhere!

ST 170 has a different setup, they don't have a regulator as the ECU controls the pump instead.

Martin

lukewhite

Hi one more question I still can't find the problem think it could be the turbo actuator it is an uprated one would over boosting cause the problem that I have described ?


Thanks luke

minder

you will find that if you change the plugs and leads the problem will go away mate
mine went like it a few months ago changed the above all sorted.If your running big power though the normal plugs wont last that long mine is running 350 and got NGK LASER PLATINUM PREMIUM and 8mm high performance ht leads

lukewhite

hi thanks for replies and help i have sorted it seems to be ok. It already had uprated leads. I have turned boost down and changed coilpack and its ok for now thanks again

luke