Why am I getting knock retard@WOT with a bone stock LS1 Z28?!
06-29-2006, 10:13 PM
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Why am I getting knock retard@WOT with a bone stock LS1 Z28?! I only have 1 good run recorded with my Autotap. The following details my problem:
At 4450 RPM (first gear with an A4), I get 1.6* knock retard.
At 4943 RPM (second gear), I get 1.1* knock retard.
At 4741 RPM (third gear), I get 3.3* knock retard.
I have 53,000 miles on my LS1. The factory spark plugs were replaced with NGK-TR 55's at around 49,000 miles, but I kept the factory plug wires. I had my local dealership do a fuel injection cleaning service (that included replacing the fuel filter) at around the same mileage. Everything else is factory stock, meaning that I have no horsepower mods whatsoever. I bought the car brand-new. The air filter is a FRAM. So, Why am I getting knock retard@WOT with a bone stock LS1 Z28?
My solution for now is to replace the factory spark plug wires and to get new spark plugs (even though they're still relatively new with around 4,000 miles); replace the air filter; replace the pcv valve; maybe get another fuel injection service done (that includes replacing the fuel filter); and getting gasoline from the station at the highway rest area and not from a local gas station. Do you think doing any of the above will help? Thanks in advance for the info.
At 4450 RPM (first gear with an A4), I get 1.6* knock retard.
At 4943 RPM (second gear), I get 1.1* knock retard.
At 4741 RPM (third gear), I get 3.3* knock retard.
I have 53,000 miles on my LS1. The factory spark plugs were replaced with NGK-TR 55's at around 49,000 miles, but I kept the factory plug wires. I had my local dealership do a fuel injection cleaning service (that included replacing the fuel filter) at around the same mileage. Everything else is factory stock, meaning that I have no horsepower mods whatsoever. I bought the car brand-new. The air filter is a FRAM. So, Why am I getting knock retard@WOT with a bone stock LS1 Z28?
My solution for now is to replace the factory spark plug wires and to get new spark plugs (even though they're still relatively new with around 4,000 miles); replace the air filter; replace the pcv valve; maybe get another fuel injection service done (that includes replacing the fuel filter); and getting gasoline from the station at the highway rest area and not from a local gas station. Do you think doing any of the above will help? Thanks in advance for the info.
Last edited by damon_Z; 06-30-2006 at 06:23 AM.
06-30-2006, 07:04 AM
#6
Buy a bottle of octane booster for $3 and see if that makes a difference. I don't remember the stuff that I've used. I imagine it was STP branded. Octane boosters do work, don't listen to anyone who tells you they are all hype. I agree that some of them might just be brands trying to make a quick buck and not make a difference, but the better brands do work. I did a head/cam swap on my old 305 in my old car and the car started audibly pinging like crazy. Dumped a bottle of octane booster into the 87 octane gas (yeah....didn't think ahead before the swap) and the pinging went away instantly.
I'd say just do that to see if its a problem with the gas you're using. Could try gas from a different station as well like you mentioned.
Could also try running a bottle of Seafoam through the car and see what happens.
I'd say just do that to see if its a problem with the gas you're using. Could try gas from a different station as well like you mentioned.
Could also try running a bottle of Seafoam through the car and see what happens.
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06-30-2006, 09:10 AM
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Getting engine temp under control is definitely a key
step. Just fan settings, to keep it from swinging up
to 226F sitting still and going to hell from there.
The fuel filter will slowly degrade your high-flow fuel
pressure as it crusts up, without giving much sign at
the lower, closed-loop range.
Single injector delivery problems likewise will show
little or no indication at lower flows, but limit the
shot into one cylinder as sediment obstructs the
screen. Factory misfire settings mask high-RPM,
WOT misfires so you don't get a good indication.
Some tools let you do injector balance tests which
might help you determine if this is going on (used
to be, you'd just pull the plugs but pulling some of
the plugs kind of sucks, here).
step. Just fan settings, to keep it from swinging up
to 226F sitting still and going to hell from there.
The fuel filter will slowly degrade your high-flow fuel
pressure as it crusts up, without giving much sign at
the lower, closed-loop range.
Single injector delivery problems likewise will show
little or no indication at lower flows, but limit the
shot into one cylinder as sediment obstructs the
screen. Factory misfire settings mask high-RPM,
WOT misfires so you don't get a good indication.
Some tools let you do injector balance tests which
might help you determine if this is going on (used
to be, you'd just pull the plugs but pulling some of
the plugs kind of sucks, here).
06-30-2006, 09:15 AM
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Runa can of seafoam through the brake booster line and let is sit in there an hour and then start the car again and it will help to clean out the combustion chambers. IF there is carbon build up in the chambers it can cause pinging issues.
06-30-2006, 09:35 AM
#11
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Originally Posted by Asmodeus
Sseeeeeeeeeeeeeeeeaaaaaaaaaaaaaaaaa
Ffoooooooooooaaaaaaaaaaaammmmmmmmmm!!!!!!!!
Ffoooooooooooaaaaaaaaaaaammmmmmmmmm!!!!!!!!
seafoam is the engine's answer to KY jelly. it makes an already great thing even better.
06-30-2006, 09:59 AM
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Originally Posted by ChocoTaco369
i agree. sounds like carbon buildup.
seafoam is the engine's answer to KY jelly. it makes an already great thing even better.
seafoam is the engine's answer to KY jelly. it makes an already great thing even better.
06-30-2006, 10:50 AM
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I have tried Seafoam, and it wasn' t extremely helpful, after several treatments. I did it so many times it killed a cat'. Anyways, I have tried spraying water SLOWLY into the Tb, while the car was running, so as not to bring the idle down, and thay has seemed to help more. My understanding is this was a way it was done in the old days, to clean the combustion chamber but, I definately exercise caution when I do it. It hasn' t pinged since I have done it a couple days ago.
I can only get 91 octane here though.
I can only get 91 octane here though.
06-30-2006, 11:47 AM
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Originally Posted by radz282003
I have tried Seafoam, and it wasn' t extremely helpful, after several treatments. I did it so many times it killed a cat'. Anyways, I have tried spraying water SLOWLY into the Tb, while the car was running, so as not to bring the idle down, and thay has seemed to help more. My understanding is this was a way it was done in the old days, to clean the combustion chamber but, I definately exercise caution when I do it. It hasn' t pinged since I have done it a couple days ago.
I can only get 91 octane here though.
I can only get 91 octane here though.
instead of regular seafoam, buy some seafoam deep creep. you turn off your car, put a brick on your gas pedal to open the TB and spray the deep creek in. it sits in the intake and when you start it up it cleans all the crap out. don't spray water in there!
06-30-2006, 11:54 AM
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hmm my 98 ss has 110k miles on her will his sea foam help it run better?do the auto parts sell both types of seafoam?and one gos i the brake booster line and one in the TB?how does it exit the system?or can u drive with it?
06-30-2006, 11:59 AM
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Originally Posted by MiaSSmaro98
hmm my 98 ss has 110k miles on her will his sea foam help it run better?do the auto parts sell both types of seafoam?and one gos i the brake booster line and one in the TB?how does it exit the system?or can u drive with it?