96-3.1 Lumina-TopEnd Ping Noise
shroom59
08-12-2007, 08:40 PM
Hello, man do i need some help here. About 3 weeks ago i replaced the spark plugs. The old ones had burned almost down to the thickness of a pin. Well the car ran fine up to yesterday. It just quit, stop running. You could start it up but when you let it sit there and idle, you could hear a definite pinging sound comming from the upper front drivers side.
I checked all the plugs, 1,3,5 on the backside looked good. 2 and 4 on the front looked like they had been in there for 70k miles. Black and carboned. Number 6 looked like it just came out of the box. So i reseated them all, and number six started to look like the others in the front. The ping is still there.
One of the times it exausted through the air cleaner and the master cylinder vac hose. It literley blew the hose off. Sounded like a firecracker. It seems the exaust is not properly being vented.
Now upon trying to get the valve covers off, i notice a black tube that runs from the backside drivers hooking into a couple of smaller lines on the drivers side comming around in front of the engine behind the mounts and over to the upper pulley. I thought that was my water pump on the pass side but might be the air pump. Either way its welded straight into the standing pipe comming off this pully mechanism part and has some sort of set screw on it. The standpipe has only one bolt to the housing on this. How do i get this off??. I am t hinking that perhaps the rocker arm bolts might be loose or I have a improperly seated pushrod or worse, a collasped lifter. But the knocking noise definitely comes from the 6 cyl firing. I can put a stick on it and feel the clattering.
Any idea's?? this is my kids college car and he's leaving this week hopefully. I am on till 1230 most nights. I can be reached on yahoo messenger at 10pm est. Handle: shur40k
Please respond..thanks
I checked all the plugs, 1,3,5 on the backside looked good. 2 and 4 on the front looked like they had been in there for 70k miles. Black and carboned. Number 6 looked like it just came out of the box. So i reseated them all, and number six started to look like the others in the front. The ping is still there.
One of the times it exausted through the air cleaner and the master cylinder vac hose. It literley blew the hose off. Sounded like a firecracker. It seems the exaust is not properly being vented.
Now upon trying to get the valve covers off, i notice a black tube that runs from the backside drivers hooking into a couple of smaller lines on the drivers side comming around in front of the engine behind the mounts and over to the upper pulley. I thought that was my water pump on the pass side but might be the air pump. Either way its welded straight into the standing pipe comming off this pully mechanism part and has some sort of set screw on it. The standpipe has only one bolt to the housing on this. How do i get this off??. I am t hinking that perhaps the rocker arm bolts might be loose or I have a improperly seated pushrod or worse, a collasped lifter. But the knocking noise definitely comes from the 6 cyl firing. I can put a stick on it and feel the clattering.
Any idea's?? this is my kids college car and he's leaving this week hopefully. I am on till 1230 most nights. I can be reached on yahoo messenger at 10pm est. Handle: shur40k
Please respond..thanks
jeffcoslacker
08-13-2007, 01:18 AM
It sure sounds like trouble, stuck lifters, flat cam, bent pushrods, broken valve spring or something.
I guess it's not just a bad coilpack not firing 2 cylinders? You said #6 sooted up too? Or after changing that plug to another cylinder it gunked up?
Check that the plug wires on the front bank aren't leaking spark and lighting each other off...
A $25 vacuum gauge would disclose whether it was actually having some valve related problem or if it's just an ignition miss or cross-up...
I guess it's not just a bad coilpack not firing 2 cylinders? You said #6 sooted up too? Or after changing that plug to another cylinder it gunked up?
Check that the plug wires on the front bank aren't leaking spark and lighting each other off...
A $25 vacuum gauge would disclose whether it was actually having some valve related problem or if it's just an ignition miss or cross-up...
frank6060
08-13-2007, 06:21 AM
Car running fine when you first changed plugs makes me think something else happened to cause misfire. Coil pak or maybe timing belt slipped. New Wires when plugs were changed?With condition of old plugs you described old wires were probably shot too. Plugs gapped correctly?
Blue Bowtie
08-15-2007, 12:41 PM
Since there is no timing belt on the 191 V-6, that's not a likely possibility. A timing chain might be a problem, but since it is evidently running on at least a few cylinders, that's not as likely.
As the Slacker suggested, valve train problems are not uncommon on the 191 and 207 engines.
You'll have to remove the right (passenger side) upper engine mount first. The other mounts will hold the engine in place, so there is no need to support or brace anything. You can remove the hold-down bolt from the coolant bypass tube (at the water pump) then remove the support nut halfway down the front (left) head to raise the tube out of the way. With that out of the way, the left (front) rocker cover can be removed.
Inspect the rockers and their mounts. Don't be too surprised if you find this:
http://72.19.213.157/files/3,4L1-3-5ValveTrainA.jpg
That's an indication that the engine has been over-revved, especially over-revved when not thoroughly warmed up.
If the rockers are intact (and not scattered about the head like the photo), you might want to remove them and inspect the push rods, or reconnect the coolant bypass so you can start the engine and observe the valve action.
If you remove the rockers from their pedestals, you'll need to clean the threads and heads, apply thread-locking compound, and properly torque the rocker bolts back in place. Also be aware that the exhaust and intake push rods are different lengths, and mixing them would be a bad idea.
As the Slacker suggested, valve train problems are not uncommon on the 191 and 207 engines.
You'll have to remove the right (passenger side) upper engine mount first. The other mounts will hold the engine in place, so there is no need to support or brace anything. You can remove the hold-down bolt from the coolant bypass tube (at the water pump) then remove the support nut halfway down the front (left) head to raise the tube out of the way. With that out of the way, the left (front) rocker cover can be removed.
Inspect the rockers and their mounts. Don't be too surprised if you find this:
http://72.19.213.157/files/3,4L1-3-5ValveTrainA.jpg
That's an indication that the engine has been over-revved, especially over-revved when not thoroughly warmed up.
If the rockers are intact (and not scattered about the head like the photo), you might want to remove them and inspect the push rods, or reconnect the coolant bypass so you can start the engine and observe the valve action.
If you remove the rockers from their pedestals, you'll need to clean the threads and heads, apply thread-locking compound, and properly torque the rocker bolts back in place. Also be aware that the exhaust and intake push rods are different lengths, and mixing them would be a bad idea.
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