Rattle in the upper RPMs?
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From: Winston-Salem, NC
Rattle in the upper RPMs? My 1998 SS has been sitting all winter, but was started once a month or so and let idle for ~20 minutes each time. ~2000 miles before it was put away for the winter, it received the MS3 cam, PRC dual spring kit, ported LS6 oil pump, double roller timing chain, hardened pushrods, a tune and Pacesetters into TSP true duals. The car has always been fine and I have not had the first problem out of it.
I took it out for the first time the other night, and from 5500-7000 RPMs, there is a noticeable rattle coming from the engine. The gas was from November so I assumed it was spark knock, but on a new tank of 93 I'm still getting the same "marbles in a tin can" sound. The sound is not rthymic - it is sporatic and has no pattern. The oil pressure is/was/has always been good, and the oil was changed while it was in storage. The car is nearing 60k miles, ~50 miles of driving since it was taken out of storage the other day.
It runs good at idle (no noises) and there is no noticeable power loss throughout the RPM range. The only problem/abnormalty I've seen is the rattle at WOT from 5500-7000 RPMs. It is noticeable in 1st-4th gear - have not gone fast enough to try 5th or 6th.
Any ideas/guesses/theories? About to do some major drivetrain beefing with the car, but I'm scared to spend any more money until I fix this issue!
Thanks in advance friends.
I took it out for the first time the other night, and from 5500-7000 RPMs, there is a noticeable rattle coming from the engine. The gas was from November so I assumed it was spark knock, but on a new tank of 93 I'm still getting the same "marbles in a tin can" sound. The sound is not rthymic - it is sporatic and has no pattern. The oil pressure is/was/has always been good, and the oil was changed while it was in storage. The car is nearing 60k miles, ~50 miles of driving since it was taken out of storage the other day.
It runs good at idle (no noises) and there is no noticeable power loss throughout the RPM range. The only problem/abnormalty I've seen is the rattle at WOT from 5500-7000 RPMs. It is noticeable in 1st-4th gear - have not gone fast enough to try 5th or 6th.
Any ideas/guesses/theories? About to do some major drivetrain beefing with the car, but I'm scared to spend any more money until I fix this issue!
Thanks in advance friends.
Last edited by JoeyAnderson; Mar 5, 2006 at 02:18 PM.
Your gas could have gone bad over the winter. It happens. You could have mucked up your injectors, but most likely, you're suffering from octane breakdown. See if you can get rid of all the old gas...completely. Don't dilute it with new gas...that will just lengthen the process.
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2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
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From: Winston-Salem, NC
Originally Posted by Patrick G
Your gas could have gone bad over the winter. It happens. You could have mucked up your injectors, but most likely, you're suffering from octane breakdown. See if you can get rid of all the old gas...completely. Don't dilute it with new gas...that will just lengthen the process.
I could drain the tank or run the car completely out of gas, but if there is an easier solution, that'd be nice.
The local parts store has injector cleaner and octane booster - do you think either of those would work?
You may want to try both...octane booster and fuel injector cleaner. Once you have all of the old gas completely gone, pull your plugs and check for any abnormalities (signs of detonation). You'll probably be just fine though.
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From: Brook Park, Ohio
Don't run your car completely out of gas!!!
From what I understand, running out of gas will ruin your fuel pump. I guess the fuel pump uses the gas to cool it while it's operating. When the car runs out of gas the fuel pump continues to run briefly, but there is no fuel to cool it, so it overheats and fails.
I'm no expert. I'm just conveying what someone else told me. Maybe someone can confirm this.
Jim
From what I understand, running out of gas will ruin your fuel pump. I guess the fuel pump uses the gas to cool it while it's operating. When the car runs out of gas the fuel pump continues to run briefly, but there is no fuel to cool it, so it overheats and fails.
I'm no expert. I'm just conveying what someone else told me. Maybe someone can confirm this.
Jim
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From: Winston-Salem, NC
I understand that running the car out of gas completely will also cause any kind of junk/muck that is lurking at the bottom of the tank to be sucked into the fuel system. No fun there...
I will try octane booster and fuel injector cleaner - thank you Patrick!
I will try octane booster and fuel injector cleaner - thank you Patrick!
When I picked up my 02 LE it ran alright, but not great. I didn't think much cus my other SS had full boltons. a few hundred miles later I got an SES light. Took it in and it was misfires. I road trip, some cleaner and a few tanks of gas and it ran much better.
Can you scan your computer to see if there are any codes in it?
Can you scan your computer to see if there are any codes in it?
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I'm getting the exact same setup in about a week or so. I would suggest going with a new fuel pump, if you are losing power through the rpms it could be due to not enough fuel pressure, check the pressure and see what its at. Maybe sitting with that gas gave the pump a hard time, also check your filter might be plugged.
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From: Winston-Salem, NC
Originally Posted by ssheets
Can you scan your computer to see if there are any codes in it?
Originally Posted by Flash99
I'm getting the exact same setup in about a week or so. I would suggest going with a new fuel pump, if you are losing power through the rpms it could be due to not enough fuel pressure, check the pressure and see what its at. Maybe sitting with that gas gave the pump a hard time, also check your filter might be plugged.
You ever get this fixed. I am having same issue. Thought it was oil issue (since the LS1 likes to burn oil and it goes a little low every few weeks...) but I just got an oil change and its back after like 2 weeks on not hearing it.
maybe you have said it but have you checked your oil level? i had a similar experience when i got my car out of storage, didnt check the oil after 2-3 weeks and had the same problem you do, a day later i got the low oil light though and after adding a quart it was fine. 
different perspective Do you still have cats on the car? I could be completely off base but if you have them I recommend to check them. Over time the inside honeycomb can break up a bit and rattle around sounding very similar to detonation.
Forget octane booster, try half a gallon or a full gallon of toluene or xylene from the paint store. That will boost your octane up quite a bit and tell you if it is indeed ping or not.
