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1992 Caddy Deville

The motor turns over, but it will not start.

Can someone help me try to figure out some possible problems?

Ok, there are 3 things you need for the engine to run, fuel, air and spark. Since the engine turns over we can assume that it has air. We’ll go through the step to check for spark first. Take one of the spark plug wires off of a sparkplug and place a screwdriver gently in the end of it. Hold the screwdriver near some metal part of the engine and have someone turn the key. If you have spark you can move on to the fuel side of it. Check the fuel pressure first. This is pretty easy. There is probably a test valve on the fuel rail that will look like a large tire valve. If there is fuel there, then you know that you may have a problem in the ECM or maybe something as simple as a fuse. If not then check the fuel filter, it may be clogged if that isn’t then you may have a bad fuel pump.

One way to check to see if you are getting fuel is to unplug a wire harness from an injector and plug in a noid light. If it flashes when you turn the key and crank the engine you are can be sure that your computer is working and the injectors are firing. From there you can be sure that you either have a bad fuel pump or a clogged fuel filter somewhere. From here, disconnect the fuel line before the fuel filter and ask someone to turn the key on. Make sure you have a container to catch any fuel that comes out.

If you have fuel before the filter, you may have a clogged filter, it’s a relatively cheap part and it makes sense to change it when you can anyway.

I’d go through these steps, if you still have problems, just post anything else it’s doing. From what you have said, this is about the best any of us could tell you.

You forgot one of the most important aspects…“Compression”.

Engine may turn over…but if this vehicle has a timing belt and it broke all the fuel and spark in the world…this vehicle will NEVER start.

We need more information…Let’s start with Make/Model and year.