what could be wrong with my 95 gmc jimmy it turns over but it wont start?

[Sabrina]

thought it was the plugs changed them and still the same thing all it does is turn over and over

 

[Molson02536]

thought it was the plugs changed them and still the same thing all it does is turn over and over

You need 3 things.
Compression
Good hot blue spark to all plugs.
Good gasoline and proper fuel pressure. 63-64 lbs.
If you have all 3 then move on to injector pulse to all injectors.
I think each injector is on a separate driver on that one.
Check for pulse to all of them.

You may be weak on fuel pressure, Even a couple of lbs low on a cold start will cause a no start. Double check cold start cranking fuel pressure. If under 63-62 lbs you have problems. One test is to give it a squirt of carb cleaner not starting fluid. If it starts then you have a fuel pressure problem.
Run the full fuel pressure test and post back pressures.

Here is the guide lines on testing.
Hard to start cold.
Check cold start fuel pressure.
Check engine running fuel pressure.
Check engine running on the road fuel pressure.
Then shut it off and watch for fast leak down.
Pinch off at rubber part or block off return line and check full pressure.
Later V6 and V8 gm engines should have 60-66 fuel pressure.
Cold start should be 64-65 lbs of pressure.
If you do not have full fuel pressure on a cold start the injectors will not squirt fuel. Engine running should be 60-66 lbs pressure depending on engine load. Full pressure with return pinched off should be 75-85 or more, And if it has a fast leak down after shut off the engine you have a leak.
Post back fuel pressure readings. The 75-85 is only a check on the capable full pressure of fuel pump.
If you can not find the rubber return line check full pressure by plugging return line or just or the true full pressure can be taken direct at the end fuel filter.

The other thing also you may want to check is all the electrical connection to your ignition coil and ICM which is located in the distributor cap under the rotor. It's common for condensation to from in the distributor cap from a dirty breather vent screen at the bottom of the distributor, promoting corrosion and ICM failure.

Start with the simple and see if you can get the engine running with a small spray of carb cleaner fluid in through the air intake tube to your engine, if the engine starts. Then you have a fuel delivery issue and your going to have to address that. If the engine does not start, then it's going to be an electrical problem and your going to have to address the Ignition system to find out why your engine is not starting. Keep us all posted and good luck, be glad to know your got your jimmy running 100% again soon.