Loud commotion upon start up?
04-10-2011, 03:32 PM
#1
Teching In
Thread Starter
iTrader: (1)
Join Date: Jan 2010
Location: Seattle
Posts: 48
Likes: 0
Received 0 Likes
on
0 Posts
Loud commotion upon start up? I'm looking at purchasing an 01 SS that has a TSP Magic Stick in it, amongst other mods, and upon checking it out today, I noticed a pretty loud banging sound under the hood when the car was initially started for a good 15-20 seconds. It was running a little rough because it was cold and that's a good sized cam, so I thought it may have had something to do with the motor mounts and, hence, not a big issue. However, I wanted to check with the more seasoned LS1 crowd and find out if this was a normal symptom of having such a cam in these cars, or if it's something I should maybe be more concerned about.
Any insight, info, advice greatly appreciated. Thanks, in advance!
Any insight, info, advice greatly appreciated. Thanks, in advance!
04-10-2011, 04:32 PM
#2
TECH Addict
be more specific.
banging is never good. but if there is some slight tapping right after start up that's not uncommon as it takes a few seconds for oil to circulate. if it was the motor mounts then you would be able to feel it when driving especially if it's an m6.
can you tell us how many miles are on the car, and miles on the set up? and can you tell us exactly what valvetrain is in the car? ie: what springs, pushrods, lifters etc. you should also make a note of oil pressure on cold start up, warm driving, and warm idling. you can never be too thorough when buying a modded car.
banging is never good. but if there is some slight tapping right after start up that's not uncommon as it takes a few seconds for oil to circulate. if it was the motor mounts then you would be able to feel it when driving especially if it's an m6.
can you tell us how many miles are on the car, and miles on the set up? and can you tell us exactly what valvetrain is in the car? ie: what springs, pushrods, lifters etc. you should also make a note of oil pressure on cold start up, warm driving, and warm idling. you can never be too thorough when buying a modded car.
04-10-2011, 05:00 PM
#3
I'm looking at purchasing an 01 SS that has a TSP Magic Stick in it, amongst other mods, and upon checking it out today, I noticed a pretty loud banging sound under the hood when the car was initially started for a good 15-20 seconds. It was running a little rough because it was cold and that's a good sized cam, so I thought it may have had something to do with the motor mounts and, hence, not a big issue. However, I wanted to check with the more seasoned LS1 crowd and find out if this was a normal symptom of having such a cam in these cars, or if it's something I should maybe be more concerned about.
Any insight, info, advice greatly appreciated. Thanks, in advance!
Any insight, info, advice greatly appreciated. Thanks, in advance!
04-10-2011, 05:36 PM
#5
Teching In
Thread Starter
iTrader: (1)
Join Date: Jan 2010
Location: Seattle
Posts: 48
Likes: 0
Received 0 Likes
on
0 Posts
The "banging" sounded like it was external as opposed to internal. Imagine what it would sound like of someone were tapping on your firewall with a hammer while you were in the driver's seat.
It obviously made me think "what the f#@%" right off the bat, but it then went away and the car ran fine, and pulled hard and smooth all the way to red line. When I heard it, I asked the seller what the hell it was and he told me he needed poly motor mounts...
The car only has 27k miles and the mods are probably 10k old. I don't know what springs, pushrods or liters are in it, bit I can find out. The only other engine mod is a set of prc 5.3 stage 2.5 heads.
It obviously made me think "what the f#@%" right off the bat, but it then went away and the car ran fine, and pulled hard and smooth all the way to red line. When I heard it, I asked the seller what the hell it was and he told me he needed poly motor mounts...
The car only has 27k miles and the mods are probably 10k old. I don't know what springs, pushrods or liters are in it, bit I can find out. The only other engine mod is a set of prc 5.3 stage 2.5 heads.
04-10-2011, 05:42 PM
#6
TECH Addict
The "banging" sounded like it was external as opposed to internal. Imagine what it would sound like of someone were tapping on your firewall with a hammer while you were in the driver's seat.
It obviously made me think "what the f#@%" right off the bat, but it then went away and the car ran fine, and pulled hard and smooth all the way to red line. When I heard it, I asked the seller what the hell it was and he told me he needed poly motor mounts...
The car only has 27k miles and the mods are probably 10k old. I don't know what springs, pushrods or liters are in it, bit I can find out. The only other engine mod is a set of prc 5.3 stage 2.5 heads.
It obviously made me think "what the f#@%" right off the bat, but it then went away and the car ran fine, and pulled hard and smooth all the way to red line. When I heard it, I asked the seller what the hell it was and he told me he needed poly motor mounts...
The car only has 27k miles and the mods are probably 10k old. I don't know what springs, pushrods or liters are in it, bit I can find out. The only other engine mod is a set of prc 5.3 stage 2.5 heads.
btw if not fixed header slap can cause nasty exhaust leaks and cause gremlins to appear. ask me how i know
04-10-2011, 05:44 PM
#7
Why is he selling the car? There is something not right with the car if there was a banging sound or any load noise at startup. If I were you take into consideration of tearing down the entire top end of the motor to inspect the issue and ensure everything is right. Its something you have to do when buying a modded car. You be assured the car was driven hard.
Trending Topics
04-10-2011, 05:57 PM
#8
Teching In
Thread Starter
iTrader: (1)
Join Date: Jan 2010
Location: Seattle
Posts: 48
Likes: 0
Received 0 Likes
on
0 Posts
oh ok, yeah the seller MIGHT be correct. it MAY be header slap. my car does it too if you don't let the clutch out right or slam a gear too hard(was an idiot for not swapping mounts) i would definately have a shop check it out first. and not just any shop, a shop that knows lsx cars.
btw if not fixed header slap can cause nasty exhaust leaks and cause gremlins to appear. ask me how i know
btw if not fixed header slap can cause nasty exhaust leaks and cause gremlins to appear. ask me how i know
Another odd thing it did, when slowly cruising in 2nd at around 2,000 rpm (going 15-20 through a neighborhood), was bucking as if you had let the clutch out incorrectly when you first started driving a stick. (You know you did it too...) The seller said it was because of the size of the cam. I've never driven a car with a cam that big, so i don't know if that's a valid characteristic or not.
04-10-2011, 06:07 PM
#11
TECH Addict
THAT is pretty much exactly what it sounded like... As if the motor were moving and hitting the firewall. So, the header slapping the inner fender well would make complete sense. As noted, it was right after start up when the engine was loping pretty hard and bogging down a bit, trying to find it's idle point.
Another odd thing it did, when slowly cruising in 2nd at around 2,000 rpm (going 15-20 through a neighborhood), was bucking as if you had let the clutch out incorrectly when you first started driving a stick. (You know you did it too...) The seller said it was because of the size of the cam. I've never driven a car with a cam that big, so i don't know if that's a valid characteristic or not.
Another odd thing it did, when slowly cruising in 2nd at around 2,000 rpm (going 15-20 through a neighborhood), was bucking as if you had let the clutch out incorrectly when you first started driving a stick. (You know you did it too...) The seller said it was because of the size of the cam. I've never driven a car with a cam that big, so i don't know if that's a valid characteristic or not.
as for the bucking, ms3's are pretty big but if tuned right should run fairly smooth with minimal bucking. if his bucks at 2k it's most likely the tune. again, have it checked out. at the very least take a look at his last dyno and see what his AFR was at. if he hasn't dyno'd it then that should be a red flag right there(mail order tune or w/e). or if he doesn't have the sheet, that'd be another red flag.
04-10-2011, 06:32 PM
#12
Teching In
Thread Starter
iTrader: (1)
Join Date: Jan 2010
Location: Seattle
Posts: 48
Likes: 0
Received 0 Likes
on
0 Posts
be more specific.
banging is never good. but if there is some slight tapping right after start up that's not uncommon as it takes a few seconds for oil to circulate. if it was the motor mounts then you would be able to feel it when driving especially if it's an m6.
can you tell us how many miles are on the car, and miles on the set up? and can you tell us exactly what valvetrain is in the car? ie: what springs, pushrods, lifters etc. you should also make a note of oil pressure on cold start up, warm driving, and warm idling. you can never be too thorough when buying a modded car.
banging is never good. but if there is some slight tapping right after start up that's not uncommon as it takes a few seconds for oil to circulate. if it was the motor mounts then you would be able to feel it when driving especially if it's an m6.
can you tell us how many miles are on the car, and miles on the set up? and can you tell us exactly what valvetrain is in the car? ie: what springs, pushrods, lifters etc. you should also make a note of oil pressure on cold start up, warm driving, and warm idling. you can never be too thorough when buying a modded car.
While we're at it, I may as well ask about the other "issue" here as I'm getting no responses in the transmission forum. The clutch was pretty soft and wanted to stick at the friction point, even when just cruising. I've read that this is common w/4th gens and he fix is a different master cylinder. Is that really all it is, or does it sound like this thing is going to need a clutch? It didn't slip at all, just stuck and the pedal felt like a Honda civic...
**sorry for all of the misspelled crap - I'm currently doing this from my phone which likes to make me involuntarily illiterate**
04-10-2011, 06:42 PM
#13
does it have stock motor mounts?if so with that cam and their age you mite need new motor mounts.it could be a after market Y-pipe hitting the body.the bucking sounds like a MAF or tuning thing.maybe do a leak down or compression check on a few cylinders.
04-10-2011, 06:52 PM
#14
Teching In
Thread Starter
iTrader: (1)
Join Date: Jan 2010
Location: Seattle
Posts: 48
Likes: 0
Received 0 Likes
on
0 Posts
Just found out the mods were actually done 3-4k miles ago. The pushrods are hardened 7.400 PRCs, the valve springs are PRC dual valve springs. Lifters are stock.
04-10-2011, 08:46 PM
#18
Teching In
Thread Starter
iTrader: (1)
Join Date: Jan 2010
Location: Seattle
Posts: 48
Likes: 0
Received 0 Likes
on
0 Posts
I'm unfortunately starting to think the same thing. The car is extremely clean, low mileage, etc. but I really don't feel like swapping the motor mounts and, possibly, the clutch. Even if the clutch doesn't need replacement, it's going to require some form of repair to remedy the issue. For $13,250 I may be better off waiting for something else to come along.
04-11-2011, 10:11 AM
#19
TECH Addict
I'm unfortunately starting to think the same thing. The car is extremely clean, low mileage, etc. but I really don't feel like swapping the motor mounts and, possibly, the clutch. Even if the clutch doesn't need replacement, it's going to require some form of repair to remedy the issue. For $13,250 I may be better off waiting for something else to come along.
the next time you go take a look at the car, open the hood and pull the top off of the clutch fluid resevior. if it's black in color then you seller doesn't know **** about 4th gens. if you let soot build up in the clutch fluid it will cause the peddle to stick. also if you do too hard of a pressure plate ontop of that you wont be able to shift at high rpms. an adjustable master cyclinder and speed bleeder is the fix. but you always have to keep an eye on the clutch fluid regardless.
over all the issues are pretty bread-n-butter. and if you do the installs yourself, motor mounts and master cylinder, you're only talking about $400. but because your seller is asking too much ask him to take the cost of parts and labor off of his asking price.
04-11-2011, 10:18 AM
#20
Teching In
Thread Starter
iTrader: (1)
Join Date: Jan 2010
Location: Seattle
Posts: 48
Likes: 0
Received 0 Likes
on
0 Posts
13.2 for a modded car with issues????? he's crazy. 10-11k tops.
the next time you go take a look at the car, open the hood and pull the top off of the clutch fluid resevior. if it's black in color then you seller doesn't know **** about 4th gens. if you let soot build up in the clutch fluid it will cause the peddle to stick. also if you do too hard of a pressure plate ontop of that you wont be able to shift at high rpms. an adjustable master cyclinder and speed bleeder is the fix. but you always have to keep an eye on the clutch fluid regardless.
the next time you go take a look at the car, open the hood and pull the top off of the clutch fluid resevior. if it's black in color then you seller doesn't know **** about 4th gens. if you let soot build up in the clutch fluid it will cause the peddle to stick. also if you do too hard of a pressure plate ontop of that you wont be able to shift at high rpms. an adjustable master cyclinder and speed bleeder is the fix. but you always have to keep an eye on the clutch fluid regardless.
I had assumed this was at least part of the problem, but it was worse than I imagined it could be from just not changing the fluid. As I mentioned before, it was sticking every time the pedal was released, not just under hard acceleration.
It's too bad - I really liked the car aside from these problems. However, I think my hunt is going to have to continue.