EJ20G detonation

coupe-a-loop · 01-29-2013, 02:02 PM

Hey guys, so I have a 95 sti ra ej20g closed deck. It's running robs 550 tune with 16 psi boost. At peak boost I am having pretty consistent detonation. I am running yellow injectors and a walbro 255 fuel pump. This motor was built around 8000 km ago, runs well and pulls hard just at this higher boost getting detonation. I don't believe this is a fuel deliver or fuel issue as I only use 94 Octane from chevron in Canada. The catch can is brand new as well....I'm out of ideas here guys not an expert by any means but trying to learn. Should I run a colder plug perhaps? I might just turn my boost down in the meantime as I have a grimmspeed manual boost controller, and see if that helps any. Thanks in advance for any advice.

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eg33GC · 01-29-2013, 02:07 PM

stock coil packs i assume?

is your CEL blinking?

coupe-a-loop · 01-29-2013, 02:11 PM

No actually 2002 coilpacks. CEL blinks yes but only at high boost. I can't even distinguishably hear the knock...although my ear isn't well trained, and the exhaust drowns every other sound out with ease.

coupe-a-loop · 01-29-2013, 02:36 PM

Hm, after reading the sticky on coil conversion it sounds alot like what rob experienced before he converted. I know for a fact these are converted to 2002, I did not build the motor however I know who did and know the care that was taken on this build. I suppose its possible these new 2002 are now shot?

AgentJ17 · 01-29-2013, 05:03 PM

Misfire and knock are two entirely different things. Failed coilpacks will cause a misfire. Rob's tune will trigger the CEL when the car detects knock.

You should be able to run a full 18psi with Rob's tune. Maybe get a wideband kit on your car to verify it's getting enough fuel? I think the wrong heat range and gap in spark plugs can cause knock.

coupe-a-loop · 01-30-2013, 03:08 AM

any recommended plugs? I guess it would help to know what I'm currently running. I'll try and pull one in the next couple days I'll be quite busy though. I tried to contact rob, but alas, hes a busy man.

Poppie · 01-30-2013, 07:57 AM

NGK PRF7B is normally used here in the UK.

Perhaps the knock sensor may need checking/replacing?

AgentJ17 · 01-30-2013, 04:24 PM

I'm pretty sure I'm running NGK BKR6E's (one step hotter than 7's) with about a .027" gap on each. Was running about 15.5psi on Rob's 550 tune until I threw a rod... But up until then, I didn't see the CEL blink once.

coupe-a-loop · 01-30-2013, 05:15 PM

Well for what it costs I will try replacing plugs. How likely is it that the knock sensor is malfunctioning? I really don't wann assume that until all other possibilities are explored.

Poppie · 01-30-2013, 05:46 PM

You could always remove the knock sensor and give it a clean as they can suffer corrosion but I can't say how likely it is to be failing sorry.

JFImport · 02-14-2013, 04:12 PM

Check to make sure nothing is rattling. I had this Same issue until i found out That an exhaust hanger was bust off and was vibrating at higher rpms.

coupe-a-loop · 02-14-2013, 07:03 PM

And that was tripping the knock sensor? Worth looking into for sure.

JDMFLCL · 02-15-2013, 01:15 PM

Also check for a rattling uppipe heatshield. Caused false knock readings on my car.

Smoke · 02-21-2013, 04:26 PM

What could cause the CEL blinking? Is that knock? Mine was doing that the other day. I don't think I heard any detonation because my exhaust is pretty loud and my friend's EWG was going off next to me.

jaxscuby · 02-21-2013, 08:25 PM

mis-fire can cause blinking cel..

please check your plugs..color and gap

coupe-a-loop · 02-21-2013, 11:13 PM

Ya I think plugs is where I will start. Is it more common to have misfires under high boost? Because thats really the only time I get it. I did howver notice the other day I had no time to warm the car up properly like I always do and I did get a couple quick bleeps within the first 15 seconds of driving. Saw none after it warmed up.

01-29-2013, 02:02 PM	#1
coupe-a-loop Scooby Newbie Member#: 336028 Join Date: Oct 2012 Chapter/Region: VIC Location: Vancouver BC Vehicle: 1995 v2 sti type ra Glacier White	EJ20G detonation Hey guys, so I have a 95 sti ra ej20g closed deck. It's running robs 550 tune with 16 psi boost. At peak boost I am having pretty consistent detonation. I am running yellow injectors and a walbro 255 fuel pump. This motor was built around 8000 km ago, runs well and pulls hard just at this higher boost getting detonation. I don't believe this is a fuel deliver or fuel issue as I only use 94 Octane from chevron in Canada. The catch can is brand new as well....I'm out of ideas here guys not an expert by any means but trying to learn. Should I run a colder plug perhaps? I might just turn my boost down in the meantime as I have a grimmspeed manual boost controller, and see if that helps any. Thanks in advance for any advice. * Registered users of the site do not see these ads.

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01-29-2013, 02:07 PM	#2
eg33GC Scooby Specialist Member#: 206851 Join Date: Mar 2009 Chapter/Region: MWSOC Vehicle: 99 V4 EJ20K RS	stock coil packs i assume? is your CEL blinking?

01-29-2013, 02:11 PM	#3
coupe-a-loop Scooby Newbie Member#: 336028 Join Date: Oct 2012 Chapter/Region: VIC Location: Vancouver BC Vehicle: 1995 v2 sti type ra Glacier White	No actually 2002 coilpacks. CEL blinks yes but only at high boost. I can't even distinguishably hear the knock...although my ear isn't well trained, and the exhaust drowns every other sound out with ease.

01-29-2013, 02:36 PM	#4
coupe-a-loop Scooby Newbie Member#: 336028 Join Date: Oct 2012 Chapter/Region: VIC Location: Vancouver BC Vehicle: 1995 v2 sti type ra Glacier White	Hm, after reading the sticky on coil conversion it sounds alot like what rob experienced before he converted. I know for a fact these are converted to 2002, I did not build the motor however I know who did and know the care that was taken on this build. I suppose its possible these new 2002 are now shot?

01-29-2013, 05:03 PM	#5
AgentJ17 Scooby Newbie Member#: 306411 Join Date: Jan 2012 Chapter/Region: VIC Location: Duncan, BC Vehicle: 1995 STi RA White	Misfire and knock are two entirely different things. Failed coilpacks will cause a misfire. Rob's tune will trigger the CEL when the car detects knock. You should be able to run a full 18psi with Rob's tune. Maybe get a wideband kit on your car to verify it's getting enough fuel? I think the wrong heat range and gap in spark plugs can cause knock.

01-30-2013, 03:08 AM	#6
coupe-a-loop Scooby Newbie Member#: 336028 Join Date: Oct 2012 Chapter/Region: VIC Location: Vancouver BC Vehicle: 1995 v2 sti type ra Glacier White	any recommended plugs? I guess it would help to know what I'm currently running. I'll try and pull one in the next couple days I'll be quite busy though. I tried to contact rob, but alas, hes a busy man.

01-30-2013, 07:57 AM	#7
Poppie Scooby Newbie Member#: 262422 Join Date: Oct 2010 Chapter/Region: International Location: Dorset,England Vehicle: 1998 V4 Type R Feather White	NGK PRF7B is normally used here in the UK. Perhaps the knock sensor may need checking/replacing?

01-30-2013, 04:24 PM	#8
AgentJ17 Scooby Newbie Member#: 306411 Join Date: Jan 2012 Chapter/Region: VIC Location: Duncan, BC Vehicle: 1995 STi RA White	I'm pretty sure I'm running NGK BKR6E's (one step hotter than 7's) with about a .027" gap on each. Was running about 15.5psi on Rob's 550 tune until I threw a rod... But up until then, I didn't see the CEL blink once.

01-30-2013, 05:15 PM	#9
coupe-a-loop Scooby Newbie Member#: 336028 Join Date: Oct 2012 Chapter/Region: VIC Location: Vancouver BC Vehicle: 1995 v2 sti type ra Glacier White	Well for what it costs I will try replacing plugs. How likely is it that the knock sensor is malfunctioning? I really don't wann assume that until all other possibilities are explored.

01-30-2013, 05:46 PM	#10
Poppie Scooby Newbie Member#: 262422 Join Date: Oct 2010 Chapter/Region: International Location: Dorset,England Vehicle: 1998 V4 Type R Feather White	You could always remove the knock sensor and give it a clean as they can suffer corrosion but I can't say how likely it is to be failing sorry.

02-14-2013, 04:12 PM	#11
JFImport Scooby Newbie Member#: 284597 Join Date: Jun 2011	Check to make sure nothing is rattling. I had this Same issue until i found out That an exhaust hanger was bust off and was vibrating at higher rpms.

02-15-2013, 01:15 PM	#13
JDMFLCL Scooby Specialist Member#: 180513 Join Date: May 2008 Chapter/Region: RMIC Location: Super Eurobeat Vol 193..Denver Vehicle: Baby Baby C'mon! Looka Bomba! 99 JDM GM8	Also check for a rattling uppipe heatshield. Caused false knock readings on my car.

02-14-2013, 07:03 PM	#12
coupe-a-loop Scooby Newbie Member#: 336028 Join Date: Oct 2012 Chapter/Region: VIC Location: Vancouver BC Vehicle: 1995 v2 sti type ra Glacier White	And that was tripping the knock sensor? Worth looking into for sure.

02-21-2013, 04:26 PM	#14
Smoke Scooby Guru Member#: 172486 Join Date: Feb 2008 Chapter/Region: NWIC Location: Cheney, WA Vehicle: 95 V4 STi-RA swap Stage 49.8	What could cause the CEL blinking? Is that knock? Mine was doing that the other day. I don't think I heard any detonation because my exhaust is pretty loud and my friend's EWG was going off next to me.

02-21-2013, 08:25 PM	#15
jaxscuby n00b Moderator Moderator Member#: 10613 Join Date: Sep 2001 Chapter/Region: South East Location: F L O R I D A Vehicle: 2002 USDM WRX WRB	mis-fire can cause blinking cel.. please check your plugs..color and gap

02-21-2013, 11:13 PM	#16
coupe-a-loop Scooby Newbie Member#: 336028 Join Date: Oct 2012 Chapter/Region: VIC Location: Vancouver BC Vehicle: 1995 v2 sti type ra Glacier White	Ya I think plugs is where I will start. Is it more common to have misfires under high boost? Because thats really the only time I get it. I did howver notice the other day I had no time to warm the car up properly like I always do and I did get a couple quick bleeps within the first 15 seconds of driving. Saw none after it warmed up.