PFC, recent map and misfire at high revs?
 

Guys,

Spec as follows:

Stillway stock mount intercooler
Airpump and emissions removed
Feed 80mm downpipe
decat centre section
3.5 inch catback, unsilenced (Yes its loud)
greddy intake elbow
PFC

Had the car mapped on wednesday. First off, the first turbo wont seem to boost more than 10lbs - no matter what you do to the wastegate duty and boost setting on the PFC/laptop, it never goes higher than 10lbs. Any ideas on this? what to check? I rebuilt the engine 8k ago and the turbos both felt good, not alot of play in them.

Second off, the car is misfiring at high revs - this wasnt addressed when i had it mapped as i forgot to change my spark plugs before i went (silly me! rushing) so the tuner said change the spark plugs see how it goes.

Changed the plugs, problem went away.

Blasted around for 50 miles, problem came back - slowly crept back in. First off it starts with the car just not feeling as smooth under acceleration, but as it detirorates the car starts to chuck black smoke out the back and hesistates badly. The more i reduce the boost, the less the problem happens - originally car was boosting around a bar but did show a peak of 16psi or so on my defi (i KNOW this is bad, ive turned it down since)

So i went to an event, a driver car test day thing, timed circuits etc. Car worked sorta ok,but had to keep reducing the boost. Then the stereo started acting funky, turning on and off so i thought hold on...electrical issue! I got out - noticed the bolts that hold my ignitor to the fender were loose. DOnt know if it needs an earth, but i tightened them down anyway and the problem seemed to get better.

So after the problem came back, i changed the plugs AGAIN (first time i used some trailings from my other 7 that had 200 miles on them, used all new plugs this time)

problem goes away again. Now its started creeping back in again. I've checked my alternator, its throwing 13.8 volts constantly.

I think it COULD Be an electrical issue but im not sure. SInce the mapping ive had the head unit trning itself on and off (which its stopped doing now) an ABS sensor thats gone funky (but i was driving the car VERY hard at the test day, lots of drifting, handbrake turns etc) and my air con compressor does not seem to be engaging (ive removed the air pump though, i know these run on the same circuit - do i need to mod something here? fuse is ok for air con, not sure on relay)

ON the other hand i think it may NOT be an electrical issue as new spark plugs seem to sort it for a few miles.

My plan is to fit a set of spare coils i have and change the plug wires, but before i dish out for them - can anyone else add anything here? anyone had a similar problem? Could this be an eartthing issue?

any input appreciated really.

Cheers chaps

To add to this the car misfires from 6k upwards, injector duty cycle is 97% at 15.5lbs at the rev limit (which i know is not good, so boost currently turned down a bit)

Knock levels are normal, nothing at all to write home about. Car seems perfectly fine apart from a misfire which chucks black smoke out the back when it happens, which i guess is unburnt fuel.

Wrong Forum!

If the problem goes away with new clean plugs then happens again after using them I while, and this repeats: what is causing the plugs to fail?

It is not a plug problem .

What color are the plugs and what do they look like when you pull them?

What are your air fuel ratios?

Personally I'd have it retuned and if you're seriously running 14 plus pounds of boost under constant load (even if in 10 minute cycles) on stock twins say goodbye to those puppies in the next few thousand miles.

MOVED to PFC forum.

Plugs look good when i pull them, no melting and they are a nice light brown colour.

Im currently running 13-14psi boost.

Unsure on A/f ratios - this will happen when i get the car back up to the tuner, he is going to hook up a monitor. I need to fix a vacuum leak first though.