Clicking sound above 4500RPMS.
07-08-2005, 03:23 PM
#1
Clicking sound above 4500RPMS. I have been having this problem for a while now. The car makes a clicking type of sound at WOT when the revs get above 4500rpm. The sound is definetly coming from the engine compartment. The sound gets progressively louder the closer to redline I get. I know it does this at the top of 1st and 2nd gear(not sure about top of 3rd, as I don't drive that fast). The weird thing is that it doesn't make the sound if I rev the car in neutral or park. Any ideas what it could be?
07-08-2005, 04:13 PM
#2
Does it sound like "marbles in a tin can"? That's detonation...mine does it too, although I've been able to gradually reduce it. Try running a top end cleaner through it (seafoam or GM) and see if that helps. I've been cleaning it every month or so and it seems to get better right after and then gradually worsen. Last weekend I installed a "home depot" oil catch can (I'm on the waiting list for an AMW). So far I've noticed a significant reduction in audible detonation, I'll know for sure how well its doing once I hook up my predator to it. HTH
07-08-2005, 06:03 PM
#4
Shine a flashlight into your intake through the throttle body and look for a coating of cruddy looking oil. The PCV valve is most likely blowing a nice film of oil into there causing pinging at wot. The make shift catch can I put in is using clear tubing and I can see oil film in the tube from the PCV valve to the catch can. The tube going into the intake is still clear. That was enough to prove to me that my problems were caused by the pcv system.
07-09-2005, 09:23 PM
#6
Haven't priced PCV valves. From what I have heard, a new valve will not solve the problem. Its a design fault. Really the only thing that will "cure" it is to run some sort of oil / air separator (AMW or other) between the valve and intake. Before I installed the separator I was seeing 4+ degrees of Knock Retard on my predator at WOT on the highway (short bursts in third gear). I'm going to the track tonight and will try to get some runs logged with hptuner to see if I'm still getting KR. I don't have any audible knock anymore on the highway though.
07-11-2005, 11:43 AM
#7
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LS1 knock solved with later engines? 
Since, I've just started reading these forums on knocking/pinging/consistent rat tat tat (my 98 z28 does it at 3000rpm), I'm wondering if GM ever solved the problem. It sounds like most of us here have had a problem I took my car to GM service and the only thing the guy did was clean out the carbon (I assume witha gm cleaner) . This did seem to relieve the consistent pinging for a little bit. Now it has come back. Maybe the answer is just replacing the pcv valve. Any thoughts? Trending Topics
07-11-2005, 02:10 PM
#9
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LS1's have real bad detonation problems, like said above usually from the faulty PCV design. Replacing the PCV valve isn't the answer. You need some sort of catch can to trap the oil going into the intake. AMW makes a great piece. You'll be amazed at how much oil it traps between oil changes. You'll also want to run some top end cleaner through the motor and change the plugs and they're probably fouled by now.
07-11-2005, 03:21 PM
#10
I completely agree with Martingale above.
Here's an update on my previous post...
I installed a makeshift catch can last weekend (7/3) and ran seafoam through the intake. This saturday (7/9) I went to the track and picked up just over .1 sec and 1 mph in the 1/4 mile. No other mods were done, and the track prep was actually worse than before due to rain the night before. I didn't notice any audible pinging and the engine wasn't struggling above 5000rpm like before. I ran a total of 7 times (including some hot lapping) and the times were all similar with no ping.
I installed the catch can with some clear tubing (kind of on the stiff side, but it works) and the line going from the PCV valve to the catch can is coated with oil residue. The line going to the intake from the catch can is clean. Get a catch can, run some cleaner through the intake, change your plugs if they are fouled, and your ping should go away.
Here's an update on my previous post...
I installed a makeshift catch can last weekend (7/3) and ran seafoam through the intake. This saturday (7/9) I went to the track and picked up just over .1 sec and 1 mph in the 1/4 mile. No other mods were done, and the track prep was actually worse than before due to rain the night before. I didn't notice any audible pinging and the engine wasn't struggling above 5000rpm like before. I ran a total of 7 times (including some hot lapping) and the times were all similar with no ping.
I installed the catch can with some clear tubing (kind of on the stiff side, but it works) and the line going from the PCV valve to the catch can is coated with oil residue. The line going to the intake from the catch can is clean. Get a catch can, run some cleaner through the intake, change your plugs if they are fouled, and your ping should go away.
07-12-2005, 02:43 AM
#12
Originally Posted by AronZ28
I just changed my plugs, so hopefully I'll get a pcv catch can before they get fouled again. Did AMV give you any timetable on when they'd have yours?
07-12-2005, 03:34 AM
#13
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It sounds to be like its somewhere in your valvetrain. Maybe a loose rocker, or more than one. Or, it could be your springs. If the car has a lot of hard miles on it the spring could be shot at higher rpm. If this were the problem, you would hear this noise at idle too.
I don't know why some of you mention detonation. If your car was going through this everytime you went above 4500rpm your motor would not be running to say the least. Detonation doesn't come to play until you have high comprestion and too much timing or not enough fuel. You may have fuel situation. Over 4500, the engine needs fuel, if your fuel filters needs changing and your injectors are clogged and need cleaning, you could be here . There's no telling.
I don't know why some of you mention detonation. If your car was going through this everytime you went above 4500rpm your motor would not be running to say the least. Detonation doesn't come to play until you have high comprestion and too much timing or not enough fuel. You may have fuel situation. Over 4500, the engine needs fuel, if your fuel filters needs changing and your injectors are clogged and need cleaning, you could be here . There's no telling.
07-12-2005, 02:04 PM
#14
I agree that at higher rpms the engine needs more fuel. The PCM will correct for this though by upping the injector duty cycle or reducing timing (probably both). What the PCM cannot correct for is the vacuum placed on the PCV line pulling an excessive amount of oil and oil vapor into the intake. This oil will coat the backside of the valves, top of the pistons, and the intake. Once its on there, it will "catch" some of the fuel sprayed from the injector. This causes less fuel to be available for combustion and therefore, sypmtoms of a lean condition which the PCM will only see as knock since the PCM thinks the air / fuel ratio is correct for the given throttle %, rpm, engine load, etc. The carbon deposits on the valves and tops of the pistons also cause hotspots which can lead to pre-ignition (knock) also.
I agree that just throwing on a catch can because you have these symptoms is not the answer. In my case I had already changed the fuel filter, plugs, plug wires, and used top end cleaner. After a few days of driving, I still had audible detonation above 4500rpm. After the catch can and more top end cleaner I have yet to hear any pinging or see timing being pulled on my predator tuner.
I agree that just throwing on a catch can because you have these symptoms is not the answer. In my case I had already changed the fuel filter, plugs, plug wires, and used top end cleaner. After a few days of driving, I still had audible detonation above 4500rpm. After the catch can and more top end cleaner I have yet to hear any pinging or see timing being pulled on my predator tuner.
07-13-2005, 01:56 AM
#17
Here are some pics of my setup. This is only temporary until I get my AMW can. You can see in the pics that the line going into the intake is still clean. The discoloration on the catch can inlet side hose has a nice coating of oil that the PCV valve has blown by.
