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Pontiac 2002 5.7 engine problem

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Old 09-26-2010, 08:54 PM
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Unhappy Pontiac 2002 5.7 engine problem

I have a very loud metallic sound which seems to be coming from the inside of the engine. I changed the oil and the sound is not that loud anymore, but I did find shavings in the oil. The pcv valve is not sucking any vacuum, instead the vacuum is coming out the valve cover where you put the oil through. The engine does misfire a little. I am suspecting a main or an insert from the crankshaft but I am not sure. It also seems as though compression is escaping through the valve cover cap as I mentioned earlier. Does anyone have any other possibilies? Please help.
( This information should have been on Generation III Area, sorry my mistake-For a 2002 Pontiac firebird transam 5.7)

Thank you.
Serpico

Last edited by Serpico327; 09-26-2010 at 09:13 PM. Reason: Mistake--Thanks
Old 09-27-2010, 08:21 PM
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There are many possibilities! Provide a little more background and maybe someone can help. Is this car stock? How many miles? Circumstances when it failed? You didn't mention oil pressure. Got any? And is the car smoking?

I will say that I've seen quite a few stock cars bend push rods. If the car has good oil pressure I'd expect the problem to be in the top end. I suppose I'd pull the plugs and valve covers and have a look.
Old 09-27-2010, 08:41 PM
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welcome to the site. I'm sure someone will be able to help diagnose your problem. Good luck
Old 09-27-2010, 09:22 PM
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Default Pontiac 2002 Firebird transam 5.7

Originally Posted by ShevrolayZ28
There are many possibilities! Provide a little more background and maybe someone can help. Is this car stock? How many miles? Circumstances when it failed? You didn't mention oil pressure. Got any? And is the car smoking?

I will say that I've seen quite a few stock cars bend push rods. If the car has good oil pressure I'd expect the problem to be in the top end. I suppose I'd pull the plugs and valve covers and have a look.
Hello,
The car is stock with 70,000 miles with 45 lbs of oil pressure and is not smoking ,the car is drivable with a slight miss. It happen while making a very fast turn on a traffic control. ( I also suspect a broken valve spring because of the escaping compression or a failed sparkplug but not sure until I pull the valve cover.) Also, service engine code PO102=Vacuum and PO300=Cylinder misfire detected but what about the remaining knock, the knock has diminished considerably compared to when it first started to knock at a hard metallic sound, the present sound could almost compare to a bad hydraulic lifter but a little louder. Do you have any more possibilities as to what direction I should follow?
Thanks
Serpico
Old 09-28-2010, 01:51 PM
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Originally Posted by Serpico327
Hello,
The car is stock with 70,000 miles with 45 lbs of oil pressure and is not smoking ,the car is drivable with a slight miss. It happen while making a very fast turn on a traffic control. ( I also suspect a broken valve spring because of the escaping compression or a failed sparkplug but not sure until I pull the valve cover.) Also, service engine code PO102=Vacuum and PO300=Cylinder misfire detected but what about the remaining knock, the knock has diminished considerably compared to when it first started to knock at a hard metallic sound, the present sound could almost compare to a bad hydraulic lifter but a little louder. Do you have any more possibilities as to what direction I should follow?
Thanks
Serpico
45 is normal pressure for the car at idle and it should increase toward 60 with increased RPM. P0102 is actually "Mass Air Flow (MAF) Circuit Low Input". The other code is indeed 'random misfire' and is most likely a result of whatever broke (I'm thinking something in the valve train).

I think you are on the right track. I don't really know why the noise has diminished. Perhaps whatever broke has been mashed up and it's more quiet based on that alone.

I'd pull the plugs to see which cylinder(s) is having the problem. Then look for a broken valve spring (good guess), bent push rod, failed lifter, loose rocker arm bolt, failed rocker arm bearings (Ive seen more than a few instances where the rocker's needle bearings self destruct and litter the engine with metal). Also, check the fuse box under the hood and make sure that the sensor fuse(s) has not blown, and check that the wiring to the MAF is intact and that the connection is clean (This might explain your p0102).

BTW, 70k miles is not a lot for an LS1... and I wouldn't drive it until it's fixed, or you risk doing further damage.
Old 09-28-2010, 04:03 PM
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Greetings,
I forgot to mention that at the time of this issue,it was raining and the water was up to the middle of the doors. Could water have gone into the system through the muffler, possibily destroying the oil viscosity? Thanks again for the information. I will be posting the cure for others to take notice .
Thank you,
Serpico
Old 09-28-2010, 04:43 PM
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Originally Posted by Serpico327
Greetings,
I forgot to mention that at the time of this issue,it was raining and the water was up to the middle of the doors. Could water have gone into the system through the muffler, possibily destroying the oil viscosity? Thanks again for the information. I will be posting the cure for others to take notice .
Thank you,
Serpico
Originally Posted by serpico
Hello,
The car is stock with 70,000 miles with 45 lbs of oil pressure and is not smoking ,the car is drivable with a slight miss. It happen while making a very fast turn on a traffic control.
So let me get this straight, you were driving fast on a turn in a flooded road?

Maybe you should just get rid of that car and drive a truck.

Serious note, if the car is still running and doesn't seem to be losing oil pressure, you're lucky.

Check the plugs/wires/O2 sensors
Old 09-28-2010, 06:36 PM
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So you are a submariner. Perhaps you should have gotten the amphibious option.



Sorry, I couldn't help myself.

Well, you may very well have sucked some water in through the intake (It's unlikely to have water come in through the exhaust while the car is running). It can happen pretty easily on these cars when going through deep water. The chin spoiler which is there to direct cool air to the intake will also send water up toward the intake.

Water does not compress much at all! If enough of it ends up in the combustion chamber during the compression stroke bad things follow. Broken pistons, broken connecting rods, blown head gaskets to name a few.




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