HELP no compression on cyl 3 and 4
#1
HELP no compression on cyl 3 and 4
OMG.
You've all heard, when it rains it pours. I found out today that cylinders 3 and 4 have no compression. What amazes me there is no cel. Truck actually was this way when I bought it I assume. I've had it about a year.
Looking for opinions at this point.
My limited shade tree analysis would be valve issues.?
2001 3.0 130000 miles, U vin,
Repairable? yes, no, maybe?
You've all heard, when it rains it pours. I found out today that cylinders 3 and 4 have no compression. What amazes me there is no cel. Truck actually was this way when I bought it I assume. I've had it about a year.
Looking for opinions at this point.
My limited shade tree analysis would be valve issues.?
2001 3.0 130000 miles, U vin,
Repairable? yes, no, maybe?
#2
If there is no compression on 3 and 4, it must be running pretty rough, even more so at idle _ lack of power too.
With out some compression test numbers is pretty hard to say for sure what the problem is, but probably some burnt valves.
Do the compression test and note what the gauge says.
Now add a bout a table spoon of oil into the combustion chamber and test it again.
If the compression increases, then you have a compression ring problem.
If the compression stays the same as your first test, then it's a valve problem.
Is it using any coolant ?
Any signs of white smoke in the exhaust or coolant in the oil ?
Was it ever over heated at some point ?
With out some compression test numbers is pretty hard to say for sure what the problem is, but probably some burnt valves.
Do the compression test and note what the gauge says.
Now add a bout a table spoon of oil into the combustion chamber and test it again.
If the compression increases, then you have a compression ring problem.
If the compression stays the same as your first test, then it's a valve problem.
Is it using any coolant ?
Any signs of white smoke in the exhaust or coolant in the oil ?
Was it ever over heated at some point ?
#3
If there is no compression on 3 and 4, it must be running pretty rough, even more so at idle _ lack of power too.
With out some compression test numbers is pretty hard to say for sure what the problem is, but probably some burnt valves.
Do the compression test and note what the gauge says.
Now add a bout a table spoon of oil into the combustion chamber and test it again.
If the compression increases, then you have a compression ring problem.
If the compression stays the same as your first test, then it's a valve problem.
Is it using any coolant ?
Any signs of white smoke in the exhaust or coolant in the oil ?
Was it ever over heated at some point ?
With out some compression test numbers is pretty hard to say for sure what the problem is, but probably some burnt valves.
Do the compression test and note what the gauge says.
Now add a bout a table spoon of oil into the combustion chamber and test it again.
If the compression increases, then you have a compression ring problem.
If the compression stays the same as your first test, then it's a valve problem.
Is it using any coolant ?
Any signs of white smoke in the exhaust or coolant in the oil ?
Was it ever over heated at some point ?
ZERO compression. like none, on either cylinder. Wet compression same result. Pulling wires from coil when running on those two makes no change in the way it runs.
Yes, slightly a rough idle...
#4
RF Veteran
iTrader: (1)
More than a "rough idle"
You would be limping around town if you drove it anywhere.
1/3 of the engine is not working
So start from the beginning
What is the compression on ALL the other cylinders, have to have that for comparison
1
2
3 0 psi
4 0psi
5
6
Fill in the blanks :)
Yes, even with 0 psi you still need a base line
You need to have ALL spark plugs removed for compression test, need good fast crank speed to get usable results
And you need to use a screw in gauge not a "hold in place" gauge
0psi is either a burnt exhaust valve or broken valve spring
Do you remember if engine ever pinged/knocked?
pinging is pre-ignition which is not uncommon with the 3.0l because of 9.3:1 compression ratio and regular gas, 87 octane
Pinging overheats a cylinder which will burn exhaust valves, can even burn a hole in the piston
You would be limping around town if you drove it anywhere.
1/3 of the engine is not working
So start from the beginning
What is the compression on ALL the other cylinders, have to have that for comparison
1
2
3 0 psi
4 0psi
5
6
Fill in the blanks :)
Yes, even with 0 psi you still need a base line
You need to have ALL spark plugs removed for compression test, need good fast crank speed to get usable results
And you need to use a screw in gauge not a "hold in place" gauge
0psi is either a burnt exhaust valve or broken valve spring
Do you remember if engine ever pinged/knocked?
pinging is pre-ignition which is not uncommon with the 3.0l because of 9.3:1 compression ratio and regular gas, 87 octane
Pinging overheats a cylinder which will burn exhaust valves, can even burn a hole in the piston
Last edited by RonD; 05-26-2017 at 05:51 PM.
#6
RF Veteran
iTrader: (1)
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