Razor2001

Hi all,

I have a JDM STI-7.

All of a sudden when I punch it hard after about 3 - 4,000 rpms it feels like it is misfiring / choking / trying to clear its throat but can't ? Boost and everything else looks ok but you can just feel the car trying to unleash its usual fury but it never really takes off ? Almost feels like when you are wot and tyres are slipping ? Its not the clutch as rpms are steady underload.

I had a friend in the car with me and he thinks it may be spark plugs or 'coil packs' ???

Any thoughts or ideas ?

Car only has 20,000 kms with a few mods: full turbo back decat and EcuTek remmap. approx 330 bhp

Cheers,
Ray

god, anyone ? big thanks ?

Razor2001

please help

Razor2001

pretty please

dowser

Had similar caused by plugs on a classic before. Does it disappear or get better when you turn down boost (connect rubber hose between turbo output and wastegate for .7ish bar).

Careful though - it could also be detting it's nuts off due to bad fuel or failed sensor. Do you have a knocklink?

Richard

Razor2001

Hey Dowser,

It drives beautifully and idles perfectly, you wouldn't even know its a problem....but under load like WOT etc is when it feels like its breaking down. Even under about 3/4 throttle with roughly .7 bar boost it feels perfect and accellerates nicely, its only under WOT or load like uphill etc.

I do not have a knock link but no error warnings or CEL's on the DD. I did a log and everything seems to look ok.

Any ideas or things I should look for in the DD runs ?

Cheers,
Ray

dowser

Is it pulling timing on knock correction under WOT? What advance multiplier is it on?

If these are 'as normal' (well, they wont be as normal because WOT wont be giving as much airflow as normal, but equally it shouldn't be pulling timing either) then it could be spark plugs - not heard of similar issues on new-age STi's, but would be worth trying a new set...maybe even a colder plug (but what boost and what fuel are you using?).

Richard

Razor2001

Hi,

The knock correction etc looks normal on the logs. Very similar to previous runs before the problem started.

I have never changed the plugs and it currently has 20,000 kms. I have replacement plugs that are supposibly exactly the same as the stock plugs (NGK R PFR 7G). The came from Subaru Japan and should be the exact replacement for my JDM STI-7.

The car has been mapped for 98 RON and that is what I have been running. From what I can tell it is not detting (although I could be wrong). Everything feels perfect except under load and WOT and all DD runs look great. I have been running this car for more than 6 months on the current setup so unless something has changed that I don't know about then its not a knock issue (I hope )

Cheers,
Ray

Razor2001

Sorry forgot boost. Currently max boost is 1.25 in 4th gear and obviously trickles down as it goes higher in the rev range.

dowser

Sounds like plugs then - make sure you gap the replacements correctly first. I use .7mm on the classics with this plug.

Richard
PS: 330ps with 1.25 bar in 4th sounds optimistic on the stock turbo

Razor2001

Thanks

I am guessing 330 BHP by repetitive runs (avg. in both directions) 250 - 260 whp road delta dash dyno runs ? Isn't 250 - 260 whp roughly 330 bhp ? Don't forget it's a STI7 with full turbo back zorst, DD scooby sport remmaped ecu.....doesn't the variable timing make a big difference on the new models vs. the older models even with similar turbo and boost or does it simply help with more torque better torque curve ?

Cheers,
Ray

Razor2001

Oh yea,

I also have another intermitent problem....nothing to do with the misfiring ( I don't think at least). Everynow and then when I try and start the car it is completely dead, however, the battery is not dead because the windows radio etc works perfectly. It is almost like the ignition is not registering that I have turned the key to fire her up....no turn over no nothing, not one sound ? I guess it could be the sensor that senses the clutch is not pressed in because it is a JDM the same exact thing happens when the clutch is not pressed in ?

Thoughts on this please ?

Hey Scooby Sport guys what spark plugs should I be using with my JDM STI-7 with full SS decat turbo back and mail in remmap for 98 RON gas running 1.25 bar peak ? are the stock ones ok ?

Cheers,
Ray

Razor2001

bttt

Pete, Pat, John, Bob etc ?

Thanks

Razor2001

bttt

dowser

try .7mm - works on the classics.

Razor2001

Thanks Dowser,

Pat, Pete etc is this ok to do and has anyone ever done it before on the new age JDM STI7's ?

What is the stock JDM STI-7 spark plug gap ?

Cheers,
Ray

Razor2001

bttt

I have it booked in on Wednesday but I want to have some info to tell the mechanics as they are not Scooby dudes

Cheers,
Ray

Razor2001

bttt

smellyvag

Razor,

I had exactly the same thing this weekend with my 99 sti5. I took all plugs out and made sure they were .7, this didnt cure it. I changed maf and its runs sweet now.

It was idling fine and boosting fine the same as yours, but just missing every now and again at about 3500rpm.

Good luck

Razor2001

Thanks for that smell. Is there anyway to check if the MAF is messed up ? Is there something on Delta Dash that can tell me if the MAF is ok or not on a JDM STI7 ?

Big thanks guys as I don't want my MAF to be messed up and running lean ready to blow up.

Thanks,
Ray

dowser

Never heard of a MAF failure on an STi7?

Richard

smellyvag

Dowser,

Plugged a delta dash into mine and it showed maf as fine, even though clearly there was something wrong.

dowser

But it must have shown as reduced airflow, no? Don't get me wrong, I know they're a consumable on the classics, just never heard or seen of a fugly STi MAF problem on the cars I've known or done.

Richard