Replaced the water pump on 96 nissan maxima. timing did not get messed with at all. i had pulled the timing cover but the chain looked good and there was no way it could have jumped time. my obd scanner shows a knock sensor issue (well known fault on 3.0). my cam sensor ohm checks good. my crank sensor shows 573 and a second one i picked up shows 566 (range is 470 to 570). is this my problem or am i missing somethimg?

I thin your mistaing the slow crank with the engine trying to start. The battery needs to be fully charged, or install a good new hot battery just to make sure that low voltage isn't the problem. You have a voltmeter, connect it to the battery and see what the voltage is when cranking it has to be above 10 volts or the ingtion and the fuel will shut off. standard test need to be performed just to see where the problem lies. Sparp fuel and compression, it's got to have them all. your car is a coil pack car so you remove the wire connector from a coil pack and connect the ground side of your test light to the battery positive and as you touch ground the light will light. with the key on one wire at the connecter won't light the light thats battery power from the key. turn th key off and the light will light. turn the key back on and test the other two wires one will light the light and the other will not. this wirewith it cranking should flash the light if it does you have spark. next is fuel, The fuel filter is behind the engine on the drivers side. grab the hose going to it and sort of fold it in half and while holding it turn on the key the fuel pump will come on for a second and you'll feel the pressure going though the hose if you do you have fuel pressure, You might not have injector pulse though. If you have fuel pressure and spark, then you need to check injector pulse , disconnect on of the connectors on a fuel injector, connect your test light like before to positive power on the battery with the key off one wire will be ground and light the light , the other wire is the pulse. with it connected to the light crank the engine and the wire should flash the light. if it does you have injector pulse. do connect the test light to groud and make sure that the other wire is hot with the key on. if it's not you have a fuse blown for the ingtion. the check engine light does come on with the key does'nt it? If it does'nt your looking for ecm power fuseand ecm ground problems the ecm gets it's ground from the wire that is bolted to the intake maniflod near the fuel injectors. You did'nt leave off any ground wires while changing the water pump, as they are all needed. Compression is last but if it was running OK before you worked on it and you didn't disturb the timing chain then it' has no reason to be different than is was. But let's say in all this work you've gotton te plugs fouled with gas oil or antifrezze you'll have to remove a coil pack and then the spark plug to see. with the plug out and the coil unplugged crank the engine and see what blows out of the cyclinder. if it's clear and some gas vapors shoot out good you know the injectors are sending fuel and theirs no water in the cyclinder. Clean the plug by burning off with a tourch and reinstall. if it was gas wet then do the rest of them too. while the plug is out do a compression test ut screwing in a compression tester, it should be over 150 lbs to 170. less than 100 your in troble. if it is low take the timing cover back off and line up the marks and count the links as in the service manul and see what you got it off by. if it needs to be changed to get it right turn it only the way that goes towards the right way as the other way you can hit the pistons and valves together. All nissan engines will hit if out of time but one thooth off won't break em. with the timing off the crank and cam sensers won't line up and the enginemanagement system won't let the motor run. I thin your mistaing the slow crank with the engine trying to start. The battery needs to be fully charged, or install a good new hot battery just to make sure that low voltage isn't the problem. You have a voltmeter, connect it to the battery and see what the voltage is when cranking it has to be above 10 volts or the ingtion and the fuel will shut off. standard test need to be performed just to see where the problem lies. Sparp fuel and compression, it's got to have them all. your car is a coil pack car so you remove the wire connector from a coil pack and connect the ground side of your test light to the battery positive and as you touch ground the light will light. with the key on one wire at the connecter won't light the light thats battery power from the key. turn th key off and the light will light. turn the key back on and test the other two wires one will light the light and the other will not. this wirewith it cranking should flash the light if it does you have spark. next is fuel, The fuel filter is behind the engine on the drivers side. grab the hose going to it and sort of fold it in half and while holding it turn on the key the fuel pump will come on for a second and you'll feel the pressure going though the hose if you do you have fuel pressure, You might not have injector pulse though. If you have fuel pressure and spark, then you need to check injector pulse , disconnect on of the connectors on a fuel injector, connect your test light like before to positive power on the battery with the key off one wire will be ground and light the light , the other wire is the pulse. with it connected to the light crank the engine and the wire should flash the light. if it does you have injector pulse. do connect the test light to groud and make sure that the other wire is hot with the key on. if it's not you have a fuse blown for the ingtion. the check engine light does come on with the key does'nt it? If it does'nt your looking for ecm power fuseand ecm ground problems the ecm gets it's ground from the wire that is bolted to the intake maniflod near the fuel injectors. You did'nt leave off any ground wires while changing the water pump, as they are all needed. Compression is last but if it was running OK before you worked on it and you didn't disturb the timing chain then it' has no reason to be different than is was. But let's say in all this work you've gotton te plugs fouled with gas oil or antifrezze you'll have to remove a coil pack and then the spark plug to see. with the plug out and the coil unplugged crank the engine and see what blows out of the cyclinder. if it's clear and some gas vapors shoot out good you know the injectors are sending fuel and theirs no water in the cyclinder. Clean the plug by burning off with a tourch and reinstall. if it was gas wet then do the rest of them too. while the plug is out do a compression test ut screwing in a compression tester, it should be over 150 lbs to 170. less than 100 your in troble. if it is low take the timing cover back off and line up the marks and count the links as in the service manul and see what you got it off by. if it needs to be changed to get it right turn it only the way that goes towards the right way as the other way you can hit the pistons and valves together. All nissan engines will hit if out of time but one thooth off won't break em. with the timing off the crank and cam sensers won't line up and the enginemanagement system won't let the motor run.