Why do I not have compression in one cylinder?

Low compression on cylinder number 1 and cylinder number 2 on a 2000 Toyota Solara 2.2L engine could be caused by a few different issues. Here are a few possibilities:

1. Worn or damaged piston rings: The piston rings seal the combustion chamber and maintain compression. If the rings are worn or damaged, they may not be able to seal the combustion chamber properly, resulting in low compression.
2. Damaged or worn valves: The valves allow air and fuel to enter the combustion chamber, and allow exhaust gases to exit. If the valves are damaged or worn, they may not be able to seal the combustion chamber properly, resulting in low compression.
3. Damaged or worn cylinder walls: The cylinder walls are what the pistons move against. If the walls are damaged or worn, they may not be able to maintain proper compression.
4. Head gasket failure: The head gasket seals the combustion chamber and prevents compression from escaping. If the head gasket is damaged or blown, compression can escape, resulting in low compression.
5. Leak in the intake or exhaust system: a leak in the intake or exhaust system can cause low compression.

The dry compression test you did on cylinder 1 and 2, 80 PSI and 60 PSI respectively, are not within the normal range and indicate low compression. The wet compression test results are also not within the normal range, 95 PSI and 85

It can vary between make and model of car. However, a general rule of thumb is that 135+ average is okay. Less than 85psi is pointing at something seriously amiss in the engine.

It can vary - some cars may have 125psi as 'average' compression.

Don't expect each cylinder to give the same compression reading as there will be a fluctuation. Another general rule of thumb is that there shouldn't be more than 10% variation between the readings. That is, if cylinder No1 is 135 psi, cylinder No2 shouldn't be less than '125 ish'.

If you suspect you may have compression issues, it's quite easy to do a bit of fault finding. Warm the engine first so that the pistons are expanded in the cylinders. Then do a dry compression (normal) test.

Here's some examples of compression tests on a 4 cylinder engine:
130 127 129 127

All compression readings are within 10% of each other. Fine.

Example 2:
95 95 129 127
Here, a low compression reading on cylinder 1 and 2 suggests a problem. It may be due to a faulty head gasket/cylinder head allowing compressed gases to be transferred via the defective head gasket from one cylinder to another.

Example 3:
130 80 129 127
Cylinder No2 has a problem. It's compression is way down. The other three cylinders are fine. So .. what is the cause of the low compression on cylinder 2? It could be a broken ring/cracked piston or a burnt exhaust valve.

This is where you do a second compression test - called the 'wet' test.

Squirt some light engine oil into each cylinder. Aim for the cylinder walls so that the oil can find its way down the walls and around the piston rings. Place a rag over each spark plug hole and spin the engine to expel excess oil.

The oil that you have sprayed into each cylinder will form a 'seal' around the piston ring. Do another compression test and note down the readings. Here's example 3 again:
Example 3:
130 80 129 127
.. with the low compression on cylinder 2.

If after carrying out the 'wet' compression test you have a reading along the lines of
130 100 129 127
suggests that the bore/piston rings in cylinder 2 are at fault. The compression has increased on No2 cylinder because of the oil forming a seal around the rings.

If there is no increase in psi on the wet test i.e
130 80 129 127
This suggests a burnt exhaust valve.

0 compression doesn't make any sense. it could be valves compression Rings or head gasket. I've never heard a cylinder getting 0 compression. I would do another compression test and double check it

If the misfire is on one a particular cylinder or perhaps 2, these issues need to be addressed and checked...
1. Power to the spark plug.
2. Coils and spark plug condition.
3. Fuel supply to the cylinder
4. Air supply to the cylinder
5. Correct fuel/ air mixture to the cylinder
6. Cylinder compression. Low compression or a cylinder compression level below spec will result in a misfire. If the compression tester shows low compression in a cylinder the causes of the poor compression reading then need to be addressed.

The fault codes generated by the computer and read by an appropriate scanner will tell you which cylinder or cylinders are misfiring.

Checking the compression amounts to using a pressure measuring device either held and sealed by rubber gasket against the cylinder spark plug orfice, or could be threaded the same as your specific plug is. It is a measure of the compression pressure within your cylinder when it is on the compression stroke....meaning all valves closed and the cylinder going up toward the cylinder head resulting in compression. Reasons for low compression are worn piston rings, burnt or mis-adjusted valves, or could be a cracked cylinder wall, blown head gasket or a hole in a piston. Gasoline engines run much lower compression than diesels. For your compression pressure norm, Google in your engine or buy a service manual and it will have the specs in pounds per Sq. in.or PSI. Good Luck

You are showing 2 different problems, no compression in any cylinder and no compression in rear cylinder.

Going with no compression in any cylinder, if the camshaft is not turning you should not have compression in most cylinders. If one cylinder has both valves closed you may have some cranking resistance. Your timing chain or gear is broken. Look if you can at any openings for a PVC pipe in the valve cover or oil fill cover on the valve cover.

There is a chance you can see some valve rocker arms and if they are moving when the engine is cranked. Otherwise you will need to remove a valve cover to observe the rockers.

when you do your compression test squirt some oil in the cylinder through the spark plug hole first then check compression if you have compression then its rings. If still no compress you might have worn off cam lobes.

That cylinder should compress but you will not be able to compress by hand theres a lot of pressure, but if you have it connected to hatch and doesnt compress then the cylinder is on wrong or bad.

A compression test will tell you if your engine has good compression. An engine is essentially a self-powered air pump, so it needs good compression to run efficiently, cleanly and to start easily.

As a rule, most engines should have 140 to 160 lbs. Of cranking compression with no more than 10% difference between any of the cylinders.

Low compression in one cylinder usually indicates a bad exhaust valve. Low compression in two adjacent cylinders typically means you have a bad head gasket. Low compression in all cylinders would tell you the rings and cylinders are worn and the engine needs to be overhauled.

HOW TO CHECK COMPRESSION
Compression can be checked two ways: manually with a compression gauge, or electronically with an engine analyzer the measures cranking compression. With electronic testing, a computer analyzer estimates compression in each of the engine's cylinders by measuring slight variations in engine cranking speed.

The results correlate well with actual gauge readings, and can be completed in a matter of minutes without having to remove any spark plugs. What's more, the analyzer prints out the results of the compression test making it easy to see and compare the actual numbers.

To check compression manually with a gauge, all the spark plugs must be removed. The ignition coil must then disabled or the high tension lead grounded. If the engine has a distributorless ignition, the ignition coils must be disabled to prevent them from firing. The throttle must also be held open.

The engine is then cranked for a few seconds using a remote starter switch or a helper while a compression gauge is held in a spark plug hole.

The maximum compression reading is noted, then the process is repeated for each of the remaining cylinders.

The individual cylinder readings are then compared to see if the results are within specifications (always refer to a manual for the exact compression figures for your engine because they do vary from the ballpark figures quoted earlier).

IS IT THE RINGS OR THE VALVES?
If compression is low in one or more cylinders, you can isolate the problem to the valves or rings by squirting a little 30 weight motor oil into the cylinder through the spark plug hole and repeating the compression test. The oil temporarily seals the rings.

If the compression readings are higher the second time around, it means the rings and/or cylinder is worn. No change in the compression readings would tell you the cylinder has a bad valve.

Hope this help (remember comment and rated this).

How to Test Engine CompressionAn engine depends on an equal compression reading in each cylinder to run smoothly. If poor compression exits in one or more cylinders it can cause a rough idle condition and low power. A compression test can be performed to check wear or internal damage. To start a engine compression test gauge is needed. There are two types of gauge styles, one threads into the spark plug hole which is more accurate. The other style of gauge is constructed with a rubber plug that is meant to be pressed against the spark plug hole, this style of gauge is difficult to use. To perform a engine cylinder compression test follow the steps below.

• Remove ignition coil connector or ignition system fuse to disable power to the ignition system
  
• Test ignition system to ensure that the power to the system has been disabled
  
• Remove #1 cylinder spark plug and insert compression gauge, most gauges have a hose attachment that is installed into the spark plug hole with the gauge connecting to the gauge hose.

Engine Cylinder Compression Gauge

• After the compression gauge has been inserted, use the starter to crank the engine over for about five seconds. Use about the same five seconds to test the remaining cylinders.
  
• Record the compression reading as each cylinder is tested
  
• Remove the compression gauge and reinsert the spark plug
  
• Follow this procedure until all cylinders have been tested
  
• Compare cylinders compression reading, all readings should be within about 5% of each other

If low compression exists a cylinder malfunction exits and further inspection is required. Possible causes for a low compression condition are: burned intake or exhaust valve, broken piston or piston ring, broken valve spring or a blown head gasket.