mrhussain

hi guys i recently bought an evo 8 fq300 last month (its my first ever evo) i love the car in terms of ease of work ability, every thing is so easy to get to compared to my other cars.

The day i bought the car it had misfire which started on the journey home (may have been before but i only noticed it on the motorway as i gave it a proper boot as i couldnt in town) when i hit around 3.5k r.p.m it starts stumbling and spluttering badly only in hard boost. when eased into the r.pm it will got all the way to redline no problem.

-so i changed the plugs to iridium's and gaped to 0.020 as i thought it maybe spark blowout from boost - DID NOT SOLVE THE ISSUE

-created a coil on plug kit using yaris coilpacks as i thought the spark may be weak - DID NOT RESOLVE THE ISSUE

-changed the fuel pump to walbro 255lph only to discover it already had a walbro in the tank, i changed it for the new one anyway - NOW this made a difference, instead of misfiring at 3.5k r.p.m im now getting better response but misfire is still there say it now kicks in at 5-6k r.p.m when giving short boost hits like traffic light to traffic light, but on the freeway it misfires epically.

NEXT on the list im waiting to change the injectors to see if that may be my issue but my question is:-

is there anything else that contributes to this type of misfire besides what i have already addressed? i read alot of similar threads regarding this misfire but feel ive changed all the parts besides injectors so far. (just waiting for a good set of used injectors to come up these things are rare)

4b11slayer

Compression and leak down test maybe in order.

Are you sure its Misfiring?

Got any codes?

mrhussain

im yet to do a compression test, but im almost certain there is no compression issue and is a misfire as no smoke is visible and oil does not seem to burn away and level is steady, ill check to rule it out

4b11slayer

Could be a valve issue not related to oil

4b11slayer

I have some stock pink injectors and am willing to ship at your expense from california u.s

mrhussain

i found a local guy selling the injectors which im going to pick up tomorrow, ill do a compression test tomorrow too before i install the replacement injectors to determine if the valves are at fault

mrhussain

on a separate note whats it like living in California, im thinking about moving to cali from here, been checking house prices and realized is so much cheaper then over here and you get a much better environment in terms of weather and scenery.

mrhussain

also the great benefit of legal medical marijuana

NigHtcRawl3R

Hey man, has the car been tuned? Sounds like fuel/boost cut.

Evo_Xela

iTrader: (1)

My car has been doing something similar. Just following to see what others thoughts are

4b11slayer

Beautiful weather.
Smog laws
No open carry
Traffic
Smog

Its alright though im born and raised here. I pay 1700 for rent 2 room duplex. Ehhh its alright. I wana move somewere like seattle.

mrhussain

i do not think my car has been tuned as its stock apart from hks air filter, aftermarket elbow with v-bank to aftermarket downpipe and full system, de-cat, walbro fuel pump.

can not see any evidence of it having a boost increase as there is no device. so i believe it to have stock tune

collecting replacement injectors today so once there installed ill see were i stand

mrhussain

i feel your pain man, i promise you will find a cure to this issue and share it on here what works but bare in mind theres a few contributing factors that cause the same symptoms.

mrhussain

man a bit of sour update.

i fit my replacement injectors in and the car ran perfect for 3 blasts, ripped right through all the r.p.m without any misfire all the way up to red line.

now it started misfiring again back to square one, any ideas guys?

also worth mentioning when i stuck the injectors in first time and started the car it triggered my engine management light with rough idle and lots of smoke was coming out of the engine but the light is gone now and is running sweet after i took it for its first rip. may have been caused by contamination of the injectors being stored or something and then cleared off by fuel cycle.

I'm now suspecting my mac so will be ordering a replacement. yet to do a compression test hopefully tomorrow.

mrhussain

but i still feel it may be fuel related as it ran great when i first stuck the injectors in, would fuel pressure have any fault in this?