99 Grand Am GT 3.4L stalls, runs rough

I was driving down the road when the car shuddered and stalled out. Was unable to start it, It wouldn't even try to turn over.

- Changed out Starter

So after replacing the starter It tried to turn over, but would almost catch and would be really rough sounding

- Changed out plugs and wires

So now the vehicle starts, but runs extremely rough and sounds terrible and eventually stalls

- I checked the plugs and wires and made sure that they are connected properly and that they are connected to the right coil and are in the right order

- I have connected a code reading computer, it does not throw any codes

- The oil light(not the "Check Oil" but the one that looks like an oil can) is on when it is running

At this point I am stuck and am not sure what to check next. I would take it to a pro but unfortunately my financial situation does not allow me this luxury. Any suggestions on what to check would be greatly appreciated.

Thanks in advance

Anyone?

Well later on today I am stopping by autozone to rent a Compression tester to see if the compression in the cylinders is good, anyone else have anything else I should check while I am at it?

Have you checked your oil, if full. You need to check your oil pressure with an oil pressure gauge. Your oil sending unit feeds power to the fuel pump. If it doesn't receive adequate oil pressure, it will shut the fuel pump down. Make sure that your oil doesn't smell like fuel also. Fuel in oil would break it down and lessen the viscosity and you'd lose oil pressure. Check for metallic flakes in oil. Its possible that your oil pump went out or sludge in the oil pump pickup caused all of this. The extra friction in the motor would keep an old starter from turning it over. Your motor may be toast. Before spending any money on parts, Ensure that the motor is not damaged.

So I got the compression tester, and here's where the problem lies I think

So the cylinders are as so

1 3 5
2 4 6

Cylinder 1 has 170psi
Cylinder 2 has 120psi
Cylinder 3 has 150psi
Cylinder 4 has 120psi but no spark(coil pack maybe?)
Cylinder 5 has 0 psi(yes Zero)
Cylinder 6 has 40 psi

Now I have read, but can't remember where, that two cylinders with low/no pressure that are in line like 5 & 6 means there could be an intake manifold gasket problem, is there any merrit to this? Otherwise I am guessing that I am going to be looking for a new engine.

Any advice is appreciated greatly.

I have also heard from my mechanic friend that it could be the rocker arms so I am going to see if I can take the valve covers off and see if they move. He said they are not supposed to so I will see how it goes.

More then likely I believe it could be also a head gasket that failed. Have you checked your oil to see if it is milky color or is your antifreeze low.

He did say it could be the head gasket, but That would mean both head gaskets would have to be gone, right?

1 3 x
2 4 x

The x's are the cylinders with no/low compression

I haven't had it overheat or even get near overheating.

We are in the process of tearing down the motor and looking at the head and seeing if that is the problem anyways. I hope we can find out what it is.

As for the oil/water, I drained the oil and water today from the motor and they look like they should, no cross contamination is present.

Your oil light is what concerns me the most. With the spark plugs out, see how hard it is to turn the motor over by with a ratchet at the crank pulley. If its really hard to turn or no turn with spark plugs out, you have most likely damaged the bearings on the bottom end. Please check this before wasting any time and money on the heads or pulling the heads. If you know someone with a bore scope, it would be wise to look into the cylinders for damage before wasting money or time on it.

So here is an update

We have the engine torn down to the lower intake manifold. The gasket was completely shot on the right hand side where the two cylinders had no compression. We are going to tear down to the heads because we had some whiteish residue in some of the ports on the lower intake manifold so we are going to check and replace the head gasket. I did try to do the test you suggested but I don't have enough clearance to get a ratchet down onto the crank pulley without taking the wheel well off. Back to it!

I would take the tire off and turn the crank. It is possible with a deepwell socket and a ratchet or breaker bar. It is of utmost importance. Why waste the money on the head gaskets of it a possibility that the bottom end is trashed? Any mechanic will tell you this. And the intake gasket hasn't a thing to do with compression. All compression is accomplished through pistons, rings, head, head gasket, and valves

I would take the tire off and turn the crank. It is possible with a deepwell socket and a ratchet or breaker bar. It is of utmost importance. Why waste the money on the head gaskets of it a possibility that the bottom end is trashed? Any mechanic will tell you this. And the intake gasket hasn't a thing to do with compression. All compression is accomplished through pistons, rings, head, head gasket, and valves


We checked this, and it turns just fine. When we took the heads off we did notice in both gaskets there were holes around where the 5th and 6th cylinders were so I think this was where the problem was. We took the heads to a shop to get cleaned up and the valves replaced and should get them back on Friday and will be putting them back on. Wish me luck.

Well we got the heads back from the shop yesterday and it turns out that the two cylinders where there was low/no compression had bent valves so this was probably an issue too. The one that had 0 compression looked like it had been stuck for a while and was very carboned on the rod part of the valve. We are working on getting the engine back together now and will post how all this turns out.

I would take the tire off and turn the crank. It is possible with a deepwell socket and a ratchet or breaker bar. It is of utmost importance. Why waste the money on the head gaskets of it a possibility that the bottom end is trashed? Any mechanic will tell you this. And the intake gasket hasn't a thing to do with compression. All compression is accomplished through pistons, rings, head, head gasket, and valves

I wouldnt agree with the bottom end being shot, could just be valve seals or a bent valve.
A little late on my responses though :lol:

Well we got the heads back from the shop yesterday and it turns out that the two cylinders where there was low/no compression had bent valves so this was probably an issue too. The one that had 0 compression looked like it had been stuck for a while and was very carboned on the rod part of the valve. We are working on getting the engine back together now and will post how all this turns out.

Very typical of these engines. Plus if you've tore it down to the heads, and its got over 100k miles, might as well pull the heads.
Especialy if you're uncertain whether it was the intake leaking, or if the head gaskets have ever been changed. It sucks to have to do it twice. :2cents:

I wouldnt agree with the bottom end being shot, could just be valve seals or a bent valve.
A little late on my responses though :lol:



Very typical of these engines. Plus if you've tore it down to the heads, and its got over 100k miles, might as well pull the heads.
Especialy if you're uncertain whether it was the intake leaking, or if the head gaskets have ever been changed. It sucks to have to do it twice. :2cents:

Well as an update I have to say the engine may be shot. We put the heads back on and we were tightening up the rocker arms. Now the guy we got the heads redone from said that we have to hand tighten the rocker arm bolts and then turn the engine until they are all hand tight all the way down otherwise you run the risk of stripping the threads in the heads so we were doing this and we noticed that the las tone on cyl 5 would not go all the way down. We turned the engine and watched all the rocker arms actuate except for two cyl on thbakc side and one cyl and one valve on the front. We were puzzled so we took a look down the engine and watched the camshaft. The entire right half of the camshaft does not move. From what I have researched on the net when this happens there is a 99% chance the bearing is spun. My father and father in law are out looking for a new motor now.

I do have one additional question.

When we get this new motor, we want to change all of the gaskets for the new ones. We already put the head gasket on the old motor but never ran the engine. We did torque the heads down properly. Is it ok to take that head gasket and place it on the new motor or would I need to get a new head gasket

Thanks

Well as an update I have to say the engine may be shot. We put the heads back on and we were tightening up the rocker arms. Now the guy we got the heads redone from said that we have to hand tighten the rocker arm bolts and then turn the engine until they are all hand tight all the way down otherwise you run the risk of stripping the threads in the heads so we were doing this and we noticed that the las tone on cyl 5 would not go all the way down. We turned the engine and watched all the rocker arms actuate except for two cyl on thbakc side and one cyl and one valve on the front. We were puzzled so we took a look down the engine and watched the camshaft. The entire right half of the camshaft does not move. From what I have researched on the net when this happens there is a 99% chance the bearing is spun. My father and father in law are out looking for a new motor now.

I do have one additional question.

When we get this new motor, we want to change all of the gaskets for the new ones. We already put the head gasket on the old motor but never ran the engine. We did torque the heads down properly. Is it ok to take that head gasket and place it on the new motor or would I need to get a new head gasket

Thanks


Busted cam shaft was something else Id thought of but wasnt sure from your description(s). Yeah that does blow!

Unfortunatly you are better off just buying new gaskets.

You might be able to get by using the new ones you torqed but it will probly leak oil on the head gaskets and leak coolant from the LI.
Even the newest LI ones with metal inserts arent realy reusable even though its not been driven.
Even those pricey head & intake bolts would need replaced because they stretch when torqed.

I done it on one of my own GA's, drove it from northern Indiana to Ohio. I got about 200 miles from home on my way back and the LI blew and over heated, even blew some oil out the head gaskets.

I just let it cool on road side, refilled fluids and babied it as far home as I could then got a buddy to come tow me back. Horrible weeked it was! :banghead:

Just my :2cents:

Busted cam shaft was something else Id thought of but wasnt sure from your description(s). Yeah that does blow!

Unfortunatly you are better off just buying new gaskets.

You might be able to get by using the new ones you torqed but it will probly leak oil on the head gaskets and leak coolant from the LI.
Even the newest LI ones with metal inserts arent realy reusable even though its not been driven.
Even those pricey head & intake bolts would need replaced because they stretch when torqed.

I done it on one of my own GA's, drove it from northern Indiana to Ohio. I got about 200 miles from home on my way back and the LI blew and over heated, even blew some oil out the head gaskets.

I just let it cool on road side, refilled fluids and babied it as far home as I could then got a buddy to come tow me back. Horrible weeked it was! :banghead:

Just my :2cents:

Thanks I was leaning on the side of getting a new pair of head gaskets, just wanted some verification.

Yea it kinda blowa but at least we didn't get the entire engine back together and then found it was toast. Just picked up a new motor and am figuring out when I am going to be able to drop it in.

Just wanted to post an update. We got the new motor stipped down and cleaned all the way down to the pistons and replaced every gasket, seal and sub $100 part we could, put everything back on and dropped it in. Hooked everything up. One wire puzzled us as it wasn't clearly marked; turned out to be the wire from the 7x crank position sensor to the coil pack. Engine cranked up on first try.

I am driving it tenderly for the first 1000 or so so all of the seals can fully engage and then will give it an oil change over to synthetic.

Thanks to all who helped me along with this, It has actually made me seriously consider becoming a mechanic(looking at schools right now as a matter of fact) as I have had a blast doing this.