valet 562t cranks no start

I double checked the ignition wire and it has power while it is cranking with the remote starter. 

Does anyone know which wire on the ecu is for the tach.  It is easier to get to there then at the instrument panel.

I found another wire that only had like .7 volts a/c it idle and went up as rpms went up.   Still didn't make a difference.  Still won't start without the key in the on position.    

I think it does have to do with the tach wire.  I went to the auto parts store and looked up the tach wire and it showed a RED / blue wire for the tach.  I got home and checked there wasn't a red blue wire on the ecm. 

I tried to disconnect the tach wire and see what happens.  It still tries to start but only cranks for about 2 seconds instead of 6 seconds. 

Would it be better to try and program it for voltage instead of tach.  I may try that Sat. just to see if it will start and run.

Any thoughts or advice would be appreciated. 

It most likely isn't an ignition circuit not being powered because if it were then the remote start would work with the key in the On position.

It can't be an OEM security issue because it won't start with the key in the On position.

Whats the temperature where you are at?  If it is extremely cold it may have something to do with the 2nd start wire.  I like to use two seperate relays to keep the two starter wires isolated.  You should be able to tap in to the small purple wire going to the relay pack and use that to power the coil of a 30A SPDT Bosch relay.  You would wire pin 30 to 12vdc (high current) and pin 87 to the 2nd starter.

Other then the 2nd starter that pretty much leaves tach.  I would switch it to voltage sense mode and see if that allows it to start.  If it does then you have pinpointed your issue.  I'm not sure how the Xterra is set up but I would recomend using a fuel injector wire - you can get the color at the injectors (the constant 12vdc side will be a common color among all injectors, you will just need to use the other wire from any of the injectors) and then trace it back to the ECU to make your connection there.

It really helps troubleshooting tach wires if you have the right tools - a meter that reads frequency would provide much better information then trying to read the signal with an AC meter.

But it does work with the key in the ON position.  I can then turn the key off and take it out and it will still run.

It's like 40 degees here.  I even tried warming the vehicle up 1st to see if that would have any effect on it.  Didn't change anything.

My meter has frequency on it I'll try that and see. 

I already know what wire on the ecm are for the injectors.  There is also a second acc wire that I didn't hook up either.  Could that  be cause a problem with something not getting voltage?

On H2 there is a factory alarm disarm and rearm that I havent hooked up yet either.  Could this have a effect on it not starting. I assumed it was to do with the door locks 

Sorry, I didn't see your update post that said it will start with the key in the "On" position, I just saw the first post that said it wouldn't.

If that is the case then it does sound like either an ignition wire or factory security issue.

To test to figure out which one it is try remote starting  the vehicle with the key in the ignition cylinder but not turned.  If it starts then the problem is a factory security issue.

If it will only remote start with the key in the "On" position (and not just in the cylinder) then you need tor recheck your ignition wires.  I doubt it would be an accessory wire, but that would be something worth checking as well.  Also, make sure you didn't hook ignition and accessory up backwards - the igntion wire needs to be energized while the starter is cranking.