Loose compression engine

I don't know liter size of engine? If cylinder misfire, it should set a trouble code for that cylinder, then you check fuel--spark--compression for that cylinder.
If you have the 2.2L engine, then the ignition module sits right on top of spark plugs. You can turn the module up side down, use a known good plug in each boot, reconnect the module wiring connector. You need to turn the assembly so metal part of spark plugs touch metal part of engine or use a jumper wire from metal part of spark plugs to metal part of engine, have a helper crank it, while you watch for spark. If you got spark everywhere, then check fuel, and so on.
If you have spark plug wires, I have found a digital multimeter is sensitive enough it will react to inductive voltage. With engine running just touch each spark plug wire in turn and take a reading. You don't penetrate the plug wire or take it loose. I have seen readings about .6 or .7 volts, the point is most of them should have close to same reading, so if you get one or two that the reading is bouncing off zero, you know where to look.
I'm not saying it will work on every year--make--model, I don't know? It has worked for me, in the past.

There are videos on you tube for diagnosing vehicle no start problems ! Rather then just replacing parts . Testing for spark and fuel pressure and engine compression . Timing chain problems etc... My advice to you would be take your vehicle to a qualified repair shop . Save yourself some money . You spent how much already ? i changed filters n spark plugs n pumps still no start !!!!!!!

wont crank fast
or cranks ok but wont start.
you must have knocked something loose. a wire or connector.
check carefully.
unless the reason for new parts, was overheating. DID IT?
if yes, compression test is next.
the 3 majors: are

1. compression over 150psi.
2. spark on all cylinders
3. and fueling correct.

1,2,3, on all gas engines. in that order too.
going backwards while fun? is fail.

I would need to know more is the belt on the right way round ?

lose compression engine has worn piston rings and worn out valves.if you have high mileage engine.

CHANGE FUEL FILTER.SQUIRT FEW DROPS OF OIL IN EACH CYLINDER REMOVE SPARK PLUGS SQUIRT A LITTLE ENGINE OIL DOWN IN THE CYLINDERS TO SEAL THE COMPRESSION RINGS BUILD UP COMPRESSION SO ENGINE WILL START.

If you have spark, and the timing is good, you are either not getting enough fuel or there is not enough compression. If you checked the spark from the spark plug wires and got a spark, try changing the spark plugs. The spark from the plugs may be too weak to ignite the fuel.

Have you changed your fuel filter? This is a very common cause of a no start condition. Have your fuel pressure tested to ensure you are getting the correct amount of fuel. Also, you could try replacing your Fuel Pressure Regulator.

I’m happy to help further over the phone at https://www.6ya.com/expert/jeremy_69f3cc28d95bf514

Anytime a car wont start its missing one of the key things it needs to start. Air, Fuel, spark or compression. The first thing to check is to pull a wire off the spark plug and put a screw drive in the end of the wire. Lay the screw driver on the engine near metal. Crank it and look for a large blue spark it should make a nice popping noise.
If no spark try the same thing with the coil wire. If spark its the cap or rotor. No spark its the coil or module.
If the plugs have spark, try pouring a small amount of gas in the throttle body and see if that starts it. If it does, fuel problem check filter and pump.
If it wont start with either or gas in the throttle body and the plugs have spark then it is either a timing or compression issue. Remove the plug wire from the center of the distrib cap and then remove the cap making sure no wires come off. Have someone crank the engine and see if the rotor spins. If it does not you need to replace the timing chain/belt. If it does spin rent a compression checker and check each cylinder.

Hope this helps.

Check all the wiring connections that you loosened or took off when you removed the head. something is loose or disconnected ,eg., ground wires .
Make sure you have spark at spark plugs whemn cranking ,and fuel pressure.
Did you try spraying starting-fluid in the intake, see if the engine runs for a little bit.
Compression to be anything above 100 psi will firean engine ,sometimes lower too.

Engine Cranks But Will Not Start

For an engine to run, you need three things to happen inside the engine. Compression, fuel and ignition, without any one of these components the engine will not run.
Basic Checks:

A. Test Fuses. Test both under hood power distribution center and the fuse panel under dash. This is done with a test light tool. The test light should illuminate on both sides of the fuse, if not the fuse has failed and needs to be replaced.
B. Testing Fuel Pressure Test for proper fuel pressure with a test gauge on the fuel rail, most throttle body injection cars (TBI) are between 13 psi and 17 psi. and most (DPI) direct port inject systems are between 40 psi and 55 psi. If no or little fuel pressure is observed and there is 12 volt power present the fuel pump, the fuel pump needs replacing.
C. Checking Timing Belt Test for compression by removing a spark plug and insert a compression gauge. Crank the engine over about 5 seconds the gauge should read between 125 psi and 165 psi, if no compression is observed remove front engine cover to inspect timing belt or chain. Crank engine to observe cam rotation, if the cam does not rotate the timing belt or chain has failed. (note: if the timing belt drives the water pump it is best to replace the water pump at this time)
D. Test for Injector Pulse Remove injector connector to insert injector test light (node) or volt meter. Observe light flash or gauge pulse while cranking. If light/voltmeter doesn't respond, an ignition distributor/crank angle sensor (CKS) or an ignition module is most likely your problem.
E. Test for Ignition Spark Remove spark plug wire, insert an extra spark plug into end of wire, rest spark plug next to a ground source then crank engine. You should observe a blue spark between the spark plug gap and ground source. If no spark is observed, an ignition coil, ignition rotor or spark plug wires might have failed. (always keep hands away from engine when cranking)