|
|
|
|
Thread Tools | Display Modes |
01-07-2014, 06:57 PM | #1 |
Scooby Newbie
Member#: 246246
Join Date: May 2010
|
Stubborn knock
I've been getting this constant knock readings between 5000-6000rpm, boost is around 16psi, AFR @ 11. fuel 93oct. The symptoms: first, IAM would drop to 14 & in some cases to 12 & then I'd get FBKC -2.11, -4.22, & some times -6.33. I know that the readings are real knock because it was audible without det cans.
Naturally, I gradually reduced timing in knock areas, but knock didn't totally disappear until I reduced an average of 15 degrees of timing down from the original rom! Now the timing table looks ridiculous! Such high, persistent knock wasn't normal to begin with on a stock rom & a moderate level of boost, so I wonder would be causing such knock, what should I look for? The car is a 2002 JDM STi EJ207
* Registered users of the site do not see these ads.
|
01-07-2014, 07:12 PM | #2 |
Scooby Specialist
Member#: 323379
Join Date: Jun 2012
Vehicle:1992 Trans Am |
|
01-07-2014, 07:31 PM | #3 |
Scooby Newbie
Member#: 246246
Join Date: May 2010
|
Last edited by leforce; 01-09-2014 at 05:16 PM. |
01-07-2014, 08:56 PM | #4 |
Scooby Guru
Member#: 103232
Join Date: Dec 2005
Chapter/Region:
Tri-State
Location: GTX3576R 05GD, GTX3076R'd FXT
Vehicle:GTX 3071R'd 11WRX PPG,4.44,LSD,E85,6spdx3 |
Have you tried giving more fuel in these areas?
|
01-07-2014, 11:44 PM | #5 |
Scooby Newbie
Member#: 246246
Join Date: May 2010
|
yes I did! I managed to 99% eliminate the knock, but that's not the point! I shouldn't have such high knock with a stock rom, normal boost to begin with, the amount to timing reduced to eliminate the knock (-15) is simply too much!
I'm suspecting that something other than the rom/map is inducing such knock, perhaps an electrical issue. |
01-09-2014, 01:13 PM | #6 |
Scooby Specialist
Member#: 323379
Join Date: Jun 2012
Vehicle:1992 Trans Am |
|
01-09-2014, 04:43 PM | #7 |
Scooby Newbie
Member#: 246246
Join Date: May 2010
|
|
01-09-2014, 07:13 PM | #8 |
Scooby Specialist
Member#: 323379
Join Date: Jun 2012
Vehicle:1992 Trans Am |
Last edited by ProfessWRX; 01-09-2014 at 07:23 PM. |
01-09-2014, 10:58 PM | #9 |
Scooby Specialist
Member#: 321409
Join Date: May 2012
Chapter/Region:
SWIC
Location: Arrey, NM
Vehicle:2003 Big Effing Van 7.3L powerstroke diesel |
Too little timing can cause knock too as does high EGT's.
Interesting thread here: http://www.romraider.com/forum/viewt...t=4670&start=0 |
01-11-2014, 01:36 PM | #10 |
Scooby Specialist
Member#: 194062
Join Date: Nov 2008
Chapter/Region:
MAIC
Location: Camp Hill PA
Vehicle:2003 Impreza WRX PSM |
What gas are you running? I was under the impression the Jdm 2 liters were high enough compression they couldn't run stock map stock boost on US spec fuel
|
01-12-2014, 07:21 AM | #11 |
Scooby Guru
Member#: 70395
Join Date: Sep 2004
Chapter/Region:
MAIC
Location: Da-boonies,Va
|
|
01-12-2014, 05:54 PM | #12 |
Scooby Newbie
Member#: 246246
Join Date: May 2010
|
I'm aware of this issue, I've been working on JDM roms for quite some time now, they are a bit aggressive but I rarely had an issue with knock when using 93 fuel. In some instances I had some mild knock that was easily eliminated by decreasing 1-2 degrees of timing.
But this time, it's a different story considering the amount of timing I had to remove to eliminate knock while using 93 fuel. Thus, I'm suspecting an electrical issue, I once had a similar problem with an Evo & the cause was a faulty ECU & got fixed by replacing the ECU. So, my next step will be to swap the ECU, flash the same rom & see how it goes. |
01-14-2014, 09:13 PM | #13 |
Scooby Specialist
Member#: 267815
Join Date: Dec 2010
Chapter/Region:
South East
Location: LSx allll done..need headers
Vehicle:Be in awe dont hate .) |
You say its a 2002? Whats the mileage?
I may have missed it but i assume you've had it apart once or twice before. But lets say its never been into. My 04 with 46000 miles was FULL of carbon and soot when I tore into her for the first rebuild.Very suprising cuz I always ran 93 oct. I do know that years of carbon and coke on the valves will severely affect the amount timing the engine can take tho. Those old F150s with the 4.6 are horrible with valve clatter caused by carbon build up. One WOT pass and it sounds like the valves are gonna fly out. Easily fixed with a couple of fuel induction services (basically sucking some seafoam equivalent **** down the intake thru various ports on the manifold). Smokes like hell during the procedure too. Idk ...maybe a issue for you...may not. I feel like that guy on reading rainbow haha "The more you know" |
Thread Tools | |
Display Modes | |
|
|