Many things-Burnt or Broken Intake or Exhaust Valves.Broken Compression Ring,Bent Push Rod,Pumped UP Hydralic Lifter,Hole in Piston or Block,,OR EVEN a small Piece of CARBON that has come loose from the Compression chamber & has gotten STUCK UNDER one of the VALVES.or a broke Valve Spring.or keepers fell off.Broken conecting Rod.
Each cylinder needs fuel, compression and spark. You are missing one of those.
This all depends on why it has low compression. If the rings are worn out, the motor should be rebuilt. If one of the valves is bad, re grinding it or replacing them is the fix. Perform a cylinder leakage test to confirm it. You will probably need to take it to a shop for this, but unfortunately, there usually are no quick fixes for low compression.
Depends on why there is no compression.
Check the Piston Ring.
Number one cylinder is located driver's side front of engine. With the # 1 piston at TDC on the compression stroke, the rotor will be pointing at #1 plug on cap.Number one cylinder is located driver's side front of engine. With the # 1 piston at TDC on the compression stroke, the rotor will be pointing at #1 plug on cap.
Remove number one spark plug and squirt some motor oil into the cylinder. Now do another compression test. If the compression goes up considerably in number one cylinder you probably have bad/worn or cracked piston rings. If the compression doesn't change much you probably have burned or bent valves.
Most of the times when you have low compression on one cylinder it's an indication that the head gasket is blown. If more than one cylinder has low compression and is hard to start the you most deffinatly have a blown head gasket
That would be the top of the compression stroke on the number one cylinder.
Oil burning or loss of compression on any one cylinder. It may also be missing on one cylinder. A compression test will verify this.
check the compression
If you are getting insulation blown upward, you most likely have a 4 cylinder engine which has a loose spark plug in the number one cylinder.
there is no hard fast rule here. but typically with the cap off and number one cylinder at TDC on compression stroke. the rotor will point at number one cylinder on the engine.