OK, so I had to put a new engine in. It's just a D15, nothing special. I get it together and go to fire it up last night, engine turns over, but won't fire. So I check my firing order (it was correct) and go to fire it again..this time it won't even turn over. All that happens is the starter 'clicks' and then nothing.

I'm thinking it might be a compression problem, but I have no way to check. So here is my question -- would the smaller radiator bypass hoses (the ones that go from header to intake manifold) cause low compression if they aren't attached? I don't have the little 4 hose adapter for them and need to get one at the junkyard (I didn't think it would keep the engine from firing, but who knows).

Sorry if that doesn't make much sense, I'm just very frustrated at the moment because I'm really not sure what the problem may be.

Edit: Uploaded a Helms manual picture and circled the hoses I'm talking about in blue.

 

You can leave those off. You need to bypass or plug everything so you can fill the radiator. Never run an engine AT ALL without coolant.

If the starter just clicks though it worked once, first check that the engine can turn freely. A major head gasket problem can let a cylinder fill with water and it will be hydo-locked. Is the battery run down? Also check the battery cables and connections, grounds, etc.

The little ECU ground wires on the thermostat housing are easy to forget when replacing an engine. With them loose or disconnected the engine will crank but not start.

 

Thank you sir, I will check all of those tonight when I mess with it. I'm thinking it might be the ground wire on the thermostat housing, because I can't remember attaching it. Hopefully it's something so simple. If anyone else has anything to add, please, feel free.