Spark Knock Help
4th Gear
Joined: Oct 2008
Posts: 4
Likes: 0
I dont mean to hijack but i am having a helluva knock problem. my tuner said the knock sensor isnt reading and i should replace it. a auto shop next to me said there are two sensors below the intake manifold is this true? and is there a way to test them instead of throwing money at the problem and hoping it works? One other thing, where the heck is the fuel filter? is it in the tank?
04 vette, tuned on ls1 edit, completley stock with a 75hp wet shot after the maf. thank you
04 vette, tuned on ls1 edit, completley stock with a 75hp wet shot after the maf. thank you
Thread Starter
Drifting
Joined: Jun 2005
Posts: 1,681
Likes: 2
From: Seven Devils NC
I dont mean to hijack but i am having a helluva knock problem. my tuner said the knock sensor isnt reading and i should replace it. a auto shop next to me said there are two sensors below the intake manifold is this true? and is there a way to test them instead of throwing money at the problem and hoping it works? One other thing, where the heck is the fuel filter? is it in the tank?
04 vette, tuned on ls1 edit, completley stock with a 75hp wet shot after the maf. thank you
04 vette, tuned on ls1 edit, completley stock with a 75hp wet shot after the maf. thank you
4th Gear
Joined: Oct 2008
Posts: 4
Likes: 0
it was throwing codes but they were vaccum codes. the car smells like gas when i fill it up so i think it has a broke vaccum line somewhere by the tank. i had it on a lift two different times and had no luck with finding the damn filter. i must be blind.
Drifting
Joined: Dec 1999
Posts: 1,541
Likes: 2
From: Raleigh NC
late 03 up - filter in the tank.
Tech Contributor
Joined: Sep 2005
Posts: 1,731
Likes: 82
From: New Market AL
The LS1/6 has 2 knock sensors, located beneath the intake manifold. If you are hearing audible knock, I would dare say the sensors are not doing their job. You really need to get someone to scan your car before you just throw parts at it. If you know someone who had HPTuners, they can scan it without having to license your car. Be carefull - you can damage your pistons with enough detonation.
Tech Contributor
Joined: Dec 2006
Posts: 10,962
Likes: 29
From: Van Buren Arkansas
Wounded Warrior Escort '11
There are several fuel lines to and from the tanks plus the cross-over tube which has been known to collapse and/or crack. There is also this little known fuel tank vent valve that has a line running from the left tank to the right rear quarter panel where this little item sets. Line is hard plastic tube.
Thread Starter
Drifting
Joined: Jun 2005
Posts: 1,681
Likes: 2
From: Seven Devils NC
Fixed I hope
Ok ..... Not quite sure what fixed it but here we go 
After Carbon Cleaning Car fell flat on its face (no power) and still had spark Knock. So off to Mayhem Motorsports here in Raleigh. So we decided to fix all the "known" problems. She had a bit of smoke after sitting and figured valve stem seals were gone. As well as a known cracked header near one of the air tubes.
Compression test came back perfect ... bout 125-120 on all cyl.
Sent header to B&B and Had them Weld the crack.
Installed Fuel Filter.
Replaced Valve Stem seals
On the road the car felt like she was way down on power more debug found that the cats were totally clogged. Restricting the exhaust We decided the best shot was to gut them.
Back on the Dyno she picked up about 7 HP No more knock noticed and car was was performing great. Its about 40 today and quite a few runs showed no knock. Will have to retest on another warmer day but I think we got her licked...
Maybe a combo of decarbon along with fuel filter solved it... but one word of caution is that decarbon procedure could cause issues with your cats... Maybe mine were partially clogged before .... but do know they were much worse off after decarb procedure..
After Carbon Cleaning Car fell flat on its face (no power) and still had spark Knock. So off to Mayhem Motorsports here in Raleigh. So we decided to fix all the "known" problems. She had a bit of smoke after sitting and figured valve stem seals were gone. As well as a known cracked header near one of the air tubes.
Compression test came back perfect ... bout 125-120 on all cyl.
Sent header to B&B and Had them Weld the crack.
Installed Fuel Filter.
Replaced Valve Stem seals
On the road the car felt like she was way down on power more debug found that the cats were totally clogged. Restricting the exhaust We decided the best shot was to gut them.
Back on the Dyno she picked up about 7 HP No more knock noticed and car was was performing great. Its about 40 today and quite a few runs showed no knock. Will have to retest on another warmer day but I think we got her licked...
Maybe a combo of decarbon along with fuel filter solved it... but one word of caution is that decarbon procedure could cause issues with your cats... Maybe mine were partially clogged before .... but do know they were much worse off after decarb procedure..
