ok, posted over in the tuning section also, thought i might get some new ideas/feedback over here. i have an 06 RS with full exhaust, intake pipe, LICP, hks twin power. its otherwise stock. since the weather has turned cooler, i have a huge misfire as soon as the car hits around 12-15 psi. its like a rev limiter misfire. i cant find any boost leaks and ive changed plugs a million times. initially i had switched to BPR8ES and then figured out that these plugs were wrong for the IX so i switched them out with brand new ILFR7Hs. the car became nearly undriveable. it would misfire right off idle....without being under boost. i had to put the BPRs back in just so i could drive it.

any ideas?

 

My car was the exact same way. Make sure the plugs are gapped because i thought mine were gapped correctly untill i got a real gapping tool and it was way to wide. Good luck!

 

ive tried gaps all the way from .020 up to .032 and everything in between.

 

What ROM is on your car.

Plugs should be gapped at .026 no higher if on stock coils.

test the coil packs

replace plug wires

pull some timing in problem area

AFR's correct?

Check your cam position sensor along with crank

check timing marks

add about 10oz of methanol to your gas incase theres water in the gas.

thats about all i know to do.


I'm willing to bet a whole lot of money you didn't gap your plugs correctly and its plug related tho.

 

what should the fuel pressure be at idle...and under boost?

 

car has stock tune. and i have no way of checking any tune related things. the car used to run great, and has slowly deteriorated to its current condition. plugs are gapped correctly. each set ive put in it has been gapped correctly. they'd have to be gapped at .060 for it to misfire like this. im running out of ideas.

 

pull off the hks twin power and just use stock ignition see if that helps also do a boost leak test

 

done that, done pressure and smoke test.

 

You're running a stock tune with these parts installed?

 

yes, stock tune for now. i cant really tune the car if it barely runs.

 

I think base fuel pressure should be 43.5ish and rise on a 1:1 ratio, 1psi of fuel pressure per 1psi of boost. You should really log it/look over the rom. Do you have a check engine light?

 

If the car isnt tuned for those parts and has the boost cut its gunna break up when going into boost. the ecu is going to sense a high load and cut the fuel so the car falls on its face. It also can be a bad coil pack or bad plug wires. Try swaping out the coils with another set and try putting the stock intake back on to see if its the fuel cut.

 

Jake, who can tune this thing in Austin?

 

You're going to need a base map for the modifications installed before you can tune. You can't install all of these parts without expecting the reliability to suffer.

 

put a base map tune on the car tonight based on very similar mods....no dice. also, installed a 255 pump, and AEM wideband today. the only thing we noticed out of the ordinary while logging is that when the misfire starts, the timing retards to almost zero. not sure why though. it didnt log knock. it really seems like there is a mechanical issue....but i dont know what would cause this, and im almost out of ideas. f u k this is frustrating.