Knock as soon as I hit boost - 3000GT/Stealth International Message Center

jcr5186 · 09-28-2007, 09:04 PM

What are some things I can look in to if I hit knock as soon as I hit boost? And the higher the boost the higher the knock. If I dont hit boost it doesnt ever knock.

Jon

thonnawan · 09-29-2007, 10:31 AM

When my car was doing this, it was because of a bad ECU. Have you checked it?

jcr5186 · 09-29-2007, 01:56 PM

I replaced the capacitors as preventative maintenance but I havent looked at it since then.

Jon

songsay ratana · 09-29-2007, 02:06 PM

i experienced the same thing.

i had to turn the boost down some, add some fuel with my safc.
get colder plugs and turn the base timing to 4 degrees.
i only have 90 octane up here.

i have 13g 15g combo
dsm intercoolers
450cc injectors
hot wired 255 fuel pump
boost at 10-12 lbs.

jcr5186 · 09-29-2007, 02:20 PM

I am running wastegate pressure (6psi). Had a MBC set at 12 and it was running fine like that for a while. I did the 120k tune up and now it is doing this. Was told its overboosting so I took the boost controller out. Still does it. I'm stumped.

Jon

jcr5186 · 10-02-2007, 06:20 PM

Bump, any other ideas?

chargerx3 · 10-02-2007, 06:47 PM

Quote:

Originally Posted by jcr5186

Bump, any other ideas?

Plug Gap???? Most common.

jcr5186 · 10-04-2007, 04:13 PM

was gapped at 40 I thought that was the problem so I gapped it down to 32 No luck.

09-28-2007, 09:04 PM	#1 (permalink)
jcr5186 Forum Member Join Date: Mar 2006 Location: Rockford, Illinois Drives: 91 Stealth r/t tt Trader Rating: (11)	Knock as soon as I hit boost What are some things I can look in to if I hit knock as soon as I hit boost? And the higher the boost the higher the knock. If I dont hit boost it doesnt ever knock. Jon __________________ Mods: Free Boost Mod, Vacuum Reduction, EGR Block Off, Rebuilt Stock Turbos (markoverclock), Test Pipe, Gutted Pre Cats, NGK Copper Plugs, Magnecor 8.5 Wires, Optima Red Top, Cone Intake, Manual Boost Controller (12psi), 120k Done!, MB Competition 17X9 Wheels, Kumho Ecsta ASX, Aluminum Y-Pipe. For Sale $5,800

09-29-2007, 10:31 AM	#2 (permalink)
thonnawan Forum Member Join Date: Jun 2005 Location: San Antonio, TX Drives: '99 SL & 91 RT/TT Trader Rating: (2)	Re: Knock as soon as I hit boost When my car was doing this, it was because of a bad ECU. Have you checked it?

09-29-2007, 01:56 PM	#3 (permalink)
jcr5186 Forum Member Join Date: Mar 2006 Location: Rockford, Illinois Drives: 91 Stealth r/t tt Trader Rating: (11)	Re: Knock as soon as I hit boost I replaced the capacitors as preventative maintenance but I havent looked at it since then. Jon

09-29-2007, 02:06 PM	#4 (permalink)
songsay ratana fly lice or chow mein Join Date: Sep 2002 Location: alaska Drives: beetle Trader Rating: (3)	Re: Knock as soon as I hit boost i experienced the same thing. i had to turn the boost down some, add some fuel with my safc. get colder plugs and turn the base timing to 4 degrees. i only have 90 octane up here. i have 13g 15g combo dsm intercoolers 450cc injectors hot wired 255 fuel pump boost at 10-12 lbs.

09-29-2007, 02:20 PM	#5 (permalink)
jcr5186 Forum Member Join Date: Mar 2006 Location: Rockford, Illinois Drives: 91 Stealth r/t tt Trader Rating: (11)	Re: Knock as soon as I hit boost I am running wastegate pressure (6psi). Had a MBC set at 12 and it was running fine like that for a while. I did the 120k tune up and now it is doing this. Was told its overboosting so I took the boost controller out. Still does it. I'm stumped. Jon

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10-02-2007, 06:20 PM	#6 (permalink)
jcr5186 Forum Member Join Date: Mar 2006 Location: Rockford, Illinois Drives: 91 Stealth r/t tt Trader Rating: (11)	Re: Knock as soon as I hit boost Bump, any other ideas?

10-04-2007, 04:13 PM	#8 (permalink)
jcr5186 Forum Member Join Date: Mar 2006 Location: Rockford, Illinois Drives: 91 Stealth r/t tt Trader Rating: (11)	Re: Knock as soon as I hit boost was gapped at 40 I thought that was the problem so I gapped it down to 32 No luck.