C5 died... :(
Thread Starter
Intermediate
Joined: Jul 2007
Posts: 49
Likes: 0
From: Seaside Heights New Jersey
C5 died... :(
Ok so my car has the G5X3 cam in it and it had a slight valve tap. The other night, my car began to misfire and I heard a constant loud *cling ca cling cling*, every time I tried to start it, it would stall unless i kept my foot on the gas. if I touched the brake it would stall. So I got it home and then next day I started it and it didn't make the noise. So today I took it around the block and it began to make the noise again and as soon as I hit the gas it stalled and I couldn't get it to start since. I'm gonna try a compression test tomorrow. I reset the codes before I went and now all I have is this "Loss of communication with BCM" code. Any ideas?
Tech Contributor
Joined: Dec 2006
Posts: 10,962
Likes: 28
From: Van Buren Arkansas
Wounded Warrior Escort '11
Well there is your clue. If the PCM and BCM won't talk, it won't run. Have you done any work in the BCM area? Any water on the passenger side floorboard? Now while its running and you hitting the gas kills it...I'm truly not sure. There are a lot of possibilities from the fuel pressure, battery connections, grounds, vacuum leaks and so on. PCV valve???
Thread Starter
Intermediate
Joined: Jul 2007
Posts: 49
Likes: 0
From: Seaside Heights New Jersey
Well it only stalled when I let off of the gas or when I hit the brakes. See I thought that maybe I blew more than one spark plug an thats why it wouldn't idle w/o me hitting the gas. But that noise was horrible, anyway I don't know what it could be. I'm going to do a compression test tomorrow and also change the oil to see if I have any metal shavings in it. Hopefully it's something stupid like fuel filter.. I don't know. I'll def let everyone know what happens though. If anyone else has any more thought on it, let me know.. Thank you.
Thread Starter
Intermediate
Joined: Jul 2007
Posts: 49
Likes: 0
From: Seaside Heights New Jersey
So the compression test came out with these results:
1: 100
2: 150
3: 65
4: 150
5: 65
6: 150
7: 175
8: 150
So 1,3, and 5 are all in a row.. Head gasket?
I won't know more until I rip the heads off, which might not be so soon..
1: 100
2: 150
3: 65
4: 150
5: 65
6: 150
7: 175
8: 150
So 1,3, and 5 are all in a row.. Head gasket?
I won't know more until I rip the heads off, which might not be so soon..
Melting Slicks
Joined: Aug 2006
Posts: 3,123
Likes: 116
From: North Dallas Forty Orange County, Ca.
St. Jude Donor '08-'09-'10-'11-'12-'13, '15,'21
I would pull the valve cover off, remove the spark plugs, and rotate by hand to see if anything happens during rotation. I had the same thing happen to me on my Mustang (suit on), turns out one of the hydraulic lifters failed and the valve was making noise as the lifter would fall off the cam lobe.
You can also try using compressed air, blow into those cylinders and see if any fluids come out. What do the spark plugs look like?
You can also try using compressed air, blow into those cylinders and see if any fluids come out. What do the spark plugs look like?
Instructor
Joined: Aug 2005
Posts: 176
Likes: 0
From: Atlanta Georgia
you could have broken a few valve springs and valve kissed a piston or 3... thats what it sounds like to me.
and fyi, if you hear a noise that really worries you, dont start the car again. its broken, take a look into it. im guessing you will end up needing a rebuild after this.
and fyi, if you hear a noise that really worries you, dont start the car again. its broken, take a look into it. im guessing you will end up needing a rebuild after this.
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Drifting
Joined: Jan 2008
Posts: 1,927
Likes: 0
From: Edmond Oklahoma
sweet jesus man. I hope you didn't hurt it worse. That cling ca cling sound was (I'd put money on it if I were a betting man) broken valvespring, valve smashing into piston. When I popped my first ls1 it was exactly the way you described. I just hope your's wasn't in as bad shape as mine was. valve hit piston, tore chunk out of piston and cylinder wall. Valve bent about 45 degrees and cracked the head. If you ever here those noises again, don't start it!!!!
Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
There was a recent post by someone who bought that cam used. The cam had lobe damage and looked like it was improperly hardened by Comp. Did this happen all of the sudden or was there some time with an increasing "tick"? Could be the cam. I would pull the valve covers first and inspect underneath. Do you have access to a boroscope? You can look into the cylinders and see if the valves have hit the pistons without removing the heads.
Thread Starter
Intermediate
Joined: Jul 2007
Posts: 49
Likes: 0
From: Seaside Heights New Jersey
I didn't take the heads off yet, but I did have a slight valve tap and everyone I know with my cam has the same tap regardless of where they had it put in. My car is the only one that broke. So I won't know what happened unit I can rip it apart and I can't until I get some time.
Pro
Joined: Jan 2008
Posts: 732
Likes: 0
From: Phoenix AZ
sweet jesus man. I hope you didn't hurt it worse. That cling ca cling sound was (I'd put money on it if I were a betting man) broken valvespring, valve smashing into piston. When I popped my first ls1 it was exactly the way you described. I just hope your's wasn't in as bad shape as mine was. valve hit piston, tore chunk out of piston and cylinder wall. Valve bent about 45 degrees and cracked the head. If you ever here those noises again, don't start it!!!!
Hope that it's not this, because it's a serious chunk of $$ to fix!
Drifting
Joined: Jan 2008
Posts: 1,927
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From: Edmond Oklahoma
Tech Contributor
Joined: Dec 2006
Posts: 10,962
Likes: 28
From: Van Buren Arkansas
Wounded Warrior Escort '11
Yeah, when I first posted in here about your issue, it sounded more like a comm issue but those cylinder tests are bad. For two cylinders to fail at the same time, I have to wonder if your timing chain jumped? I've not once heard of that happening on an LS engine, but who knows. Pull those heads off and see what you've got, but before you do, manually check the top dead center on #1 and make sure its still correct.
Drifting
Joined: Jan 2008
Posts: 1,927
Likes: 0
From: Edmond Oklahoma
Please save yourself the trouble and pull the valve covers first, if you haven't already. It takes 10-15 minutes tops. Just don't cut up your hands on those damn sharp headed nuts that GM thought was a good idea for the coil packs. I'll eat my socks if there's no broken valvesprings.
Thread Starter
Intermediate
Joined: Jul 2007
Posts: 49
Likes: 0
From: Seaside Heights New Jersey
Well eat your socks buddy cause everything 'looked' fine when I took the valve covers off. haha, but looks can be deceiving so we'll see once I have time to take it all apart.
Safety Car
Joined: Sep 2003
Posts: 3,558
Likes: 2
From: Cape Coral FL
Take your pushrods out and check them for flatness. If you kissed a piston you could have bent pushrods in addition to bent valves. Were you driving it hard before the problem? You could have floated a valve. It doesn't take much to trash a motor, ask me how I know, and I'm hoping it's something simple like your balancer. 
Safety Car
Joined: Aug 2000
Posts: 4,933
Likes: 29
From: San Rafael CA
A compression test is testing the "compression" stroke ... both valves are supposed to be closed .....
A bent valve that contacted the piston and now can't close would be one reason for low compression .... BUT .... how do you bend valves on one side of the engine and the other side appears to be "normal" .... ????? If the cam jumped the timing chain you would expect to see equal damage on both sides of the engine.
I'd go with the OP's guess and say something like the headgasket went on the driver's side of the engine ... EXCEPT ... the "cling ... cling .... cling" description sure makes you think it was a much more catastrophic failure .....
bradenW you recommended the right thing .... removing the valve cover. Next step ... remove heads .... but OUCH does this sound like it is gonna turn ugly ...
I'd pull the drivers side head first, and I'd STRONGLY consider pulling the other head also .....
Last edited by BlackZ06; Mar 17, 2008 at 03:16 AM.
