I've gotten my vortech remapped with a Utec, came in at a nice 416bhp....

However, just at the top of the rev range the car is misfiring, it's as if the plugs aren't up to the job...

I've got NGK iridiums in there, but they have been in for about 7Kmiles, would the misfiring more than likely be due to the plugs being worn or do our zed's suffer problems with their coil packs??

Cheers
Dave

 

SOunds like the tuner needs to go back over it . Dont push it till you do

 

What do you mean by the top of the rev range? 6500 and above is an ECU controlled rev limiter.

 

Believe its 6600 rpm rev limiter

 

Do you also have upgraded injectors and fuel pump? Fuel return system?

You could be leaning out at the high end...definate recipe for disaster. Better have it checked out for real.

 

it's misfiring around 6K revs, I have the limiter set at 6500...

I've got 550cc injectors and a walbro fuel pump, pulled the spark plugs and they weren't in great shape, I also pulled a diagnostic and cylinder six showed up, so going to replace the coil pack in that cylinder as well, it's still with the tuner anyhow, so I've order these bits and hopefully that will cure the problem...It's not actually leaning out at high revs according to my tuner and there is plenty of fuel there

 

Oh, here's a pick of my pulley set up, I added in two smaller ones to reduce belt slip and it's worked a treat, I know one supplier had a kit and it was only one pulley, but it was coming in at in excess of $200 which was a bit much, so decided to do it myself...
It's reduce any belt slip I had, no squell on start up and the blower seems to be quieter too!!!

 

Have you checked for blow by or oil in the piping? If you were getting oil mist at high rpm's it could cause detonation/misfire.

 

Haven't actually no, I'll get them to check that out too!!

Cheers

 

are you using colder plugs