00 Z28 sounds like pre-ignition "ping" after LS6 intake install-HELP!
03-25-2005, 11:44 AM
#1
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00 Z28 sounds like pre-ignition "ping" after LS6 intake install-HELP! As said, recently installed a LS6 intake, had the EGR codes and whatnot removed. Now the car has what sounds like a pre-ignition "ping" noise. Happens under light throttle and only when car is COLD, thinking only during open loop. Any one else have this problem? Does the computer use a pre-installed program for open loop status? Maybe have my cold start fuel trim raised?
Im running 92-93 octane, also will be checking with a TECH-2 to see what the car is doing here in a couple hours. Looking for any and all help-suggestions. THX
Im running 92-93 octane, also will be checking with a TECH-2 to see what the car is doing here in a couple hours. Looking for any and all help-suggestions. THX
03-25-2005, 11:48 AM
#2
You might want to check to make 100% sure you didn't pinch the KS sensor harness. I swore up & down I didn't... but when the intake was off recently, I saw otherwise. 
Prior to that, I was getting a PO327 code and my car was pulling lots of timing.
Prior to that, I was getting a PO327 code and my car was pulling lots of timing.
03-25-2005, 02:10 PM
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eerrgg!! Test drove with the TECH2 scanner, all parameters look good/normal. After further review with an engine guy, seems to be internal engine noise. Possibly piston slap. Just never heard it before intake install, weird.
03-25-2005, 02:15 PM
#4
Originally Posted by racinbird
eerrgg!! Test drove with the TECH2 scanner, all parameters look good/normal. After further review with an engine guy, seems to be internal engine noise. Possibly piston slap. Just never heard it before intake install, weird.
03-25-2005, 04:42 PM
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Ok, I installed a LS6 intake on my 00' Z28 M6 about two weeks ago. It has about 62,000 miles on the clock. Ever since the install I have heard a noise on COLD starts only which sounds like pinging, possile piston slap, sorta like rocks in a can. Now it dosent make this noise at idle, only once you accelerate starting around 1700-1800 rpm and continues to climb with the throttle.
It will make this noise with rpms going up with load and also when rpms are going back down. It goes away after about 5 minutes or so. Now I have had this car for a year or so and NEVER have heard this until the intake install. Is this piston slap or another issue? Also note that the EGR was removed/deleted at this time also. I could have sworn it was "pinging" but the scaner shows ignition and knock sensors normal, no codes, and I am running good 93 octane gas. Help-advise? anyone? Thanks
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It will make this noise with rpms going up with load and also when rpms are going back down. It goes away after about 5 minutes or so. Now I have had this car for a year or so and NEVER have heard this until the intake install. Is this piston slap or another issue? Also note that the EGR was removed/deleted at this time also. I could have sworn it was "pinging" but the scaner shows ignition and knock sensors normal, no codes, and I am running good 93 octane gas. Help-advise? anyone? Thanks
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03-26-2005, 08:02 PM
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You need to do more than turn off the EGR codes.
You want to turn off the whole EGR action and make
sure that the PCM doesn't think EGR is still there. The
spark table and fueling get messed around when EGR
is active, excess advance and light fueling = ping.
Though I'd think KR would be active if you were
pinging. When you say scanner, is this like an AutoZone
code scanner or a logging tool like ATAP/EFILive/HPTuners?
Can you instrument it up and drive through the warmup
phase where this happens, and see about the spark
advance and any spark knock?
You want to turn off the whole EGR action and make
sure that the PCM doesn't think EGR is still there. The
spark table and fueling get messed around when EGR
is active, excess advance and light fueling = ping.
Though I'd think KR would be active if you were
pinging. When you say scanner, is this like an AutoZone
code scanner or a logging tool like ATAP/EFILive/HPTuners?
Can you instrument it up and drive through the warmup
phase where this happens, and see about the spark
advance and any spark knock?
03-26-2005, 08:39 PM
#9
Bet you didn't edit the EGR timing table. See, the PCM adds some timing at light throttle when the EGR goes on. Even though you may have eliminated the EGR and the associated codes, the EGR timing advance will still kick in making your car ping. I know, I just added an LS6 intake and had to adjust that table with HP tuners.
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03-26-2005, 10:22 PM
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Originally Posted by Patrick G
Bet you didn't edit the EGR timing table. See, the PCM adds some timing at light throttle when the EGR goes on. Even though you may have eliminated the EGR and the associated codes, the EGR timing advance will still kick in making your car ping. I know, I just added an LS6 intake and had to adjust that table with HP tuners.
Maybe you could make a sticky-"How to properly remove EGR"
03-27-2005, 04:41 PM
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Yes, I had a local guy with LS1 edit go in and do all the necessary EGR removal stuff. He has been doing it for years.
The scanner I used was a GM Tech2 scanner, so yes, watched all fuel and timing which all looked good. Besides this noise was in open loop, so I doubt egr should have been active anyways.
After driving some more I belive it to be piston slap, there on cold starts and then goes away after a bit of driving. It is just weird timing, I have had the car over a year and just started hearing the noise a week after the intake install. The noise isnt there at idle, just under little throttle starting around 1700 rpms and goes up til around 3000 or so. really loud rattle sound, scarey.
The scanner I used was a GM Tech2 scanner, so yes, watched all fuel and timing which all looked good. Besides this noise was in open loop, so I doubt egr should have been active anyways.
After driving some more I belive it to be piston slap, there on cold starts and then goes away after a bit of driving. It is just weird timing, I have had the car over a year and just started hearing the noise a week after the intake install. The noise isnt there at idle, just under little throttle starting around 1700 rpms and goes up til around 3000 or so. really loud rattle sound, scarey.
03-27-2005, 08:00 PM
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Originally Posted by racinbird
Yes, I had a local guy with LS1 edit go in and do all the necessary EGR removal stuff. He has been doing it for years.
The scanner I used was a GM Tech2 scanner, so yes, watched all fuel and timing which all looked good. Besides this noise was in open loop, so I doubt egr should have been active anyways.
After driving some more I belive it to be piston slap, there on cold starts and then goes away after a bit of driving. It is just weird timing, I have had the car over a year and just started hearing the noise a week after the intake install. The noise isnt there at idle, just under little throttle starting around 1700 rpms and goes up til around 3000 or so. really loud rattle sound, scarey.
The scanner I used was a GM Tech2 scanner, so yes, watched all fuel and timing which all looked good. Besides this noise was in open loop, so I doubt egr should have been active anyways.
After driving some more I belive it to be piston slap, there on cold starts and then goes away after a bit of driving. It is just weird timing, I have had the car over a year and just started hearing the noise a week after the intake install. The noise isnt there at idle, just under little throttle starting around 1700 rpms and goes up til around 3000 or so. really loud rattle sound, scarey.
03-27-2005, 08:22 PM
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How many miles on the car?
I havent done it yet, but if you can get ahold of the Tech 2 again. I forget what the Tech 2 has, but I am sure it has some sort of data logger/playback. Use it when its making the noise. I would think piston slap would show on the knock sensors.
I havent done it yet, but if you can get ahold of the Tech 2 again. I forget what the Tech 2 has, but I am sure it has some sort of data logger/playback. Use it when its making the noise. I would think piston slap would show on the knock sensors.
03-27-2005, 08:38 PM
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Originally Posted by racinbird
The knock sensors didnt show any abnormal activity when it was slapping. It has just over 62,000 miles.
?? 
