How hard IS a crank sensor to change. 93 VG30DE J30.

[J30ZX]

Just wondering out loud. Previous mechanic said it would take a "special tool" ?? .. Now the car is somewhere else, I'm reading up on how "changing the sensor" can stop what I can best describe as "intermittent parasitic draw.." previous mechanic told me these things can happen if sensor is "on the way out."

Okay, as to original question. How hard IS it to change sensor, what is best sensor to replace with is there an "updated" one, is it true the best is a Nissan sensor not aftermarket, are they still available, what else gets changed at same time, how involved is it?

93 J30

[VStar650CL]

Your ride is an oldie and some other folks may know something I don't, but the wiring diagram says the Crank Sensor (actually a cam sensor on the J30) and MAF both get power from the ECCS Relay. That should be off shortly after the ignition is turned off. So I don't see how either one could cause any sort of parasitic draw unless for some reason the ECM is staying powered-up when it shouldn't be. If so, that would be an issue with the ECM or the relay and not the sensors. See EF & EC-124 here:
https://www.nicoclub.com/service-manual ... 93_FSM.pdf

[J30ZX]

Also. Is this the sensor

https://www.ebay.com/itm/154869961454?f ... BM6Pz2ivFf

[J30ZX]

I do wonder what the issue is at this point.

"ECM staying on" - Anyone ever had that happen?

[VStar650CL]

There are two electrical reasons it can happen, a stuck ECCS Relay or a melted transistor in the ECM's relay driver. The reason the ECM needs to be able to turn itself on independently of the ignition key is so it can check the fuel tank and evap canister for leakage. It does that by monitoring vacuum in the fuel tank while the car is parked, a test called EONV (Engine Off Natural Vacuum). To perform it, the ECM uses an internal MOSFET transistor to activate the coil of the ECCS Relay, which in turn powers-up the other ECM systems. This "self-wakeup" will always happen when the car is idle and you aren't looking. If the ECCS Relay contacts collapse, it will usually short out the coil and melt the MOSFET into a permanent short-circuit that keeps the ECM on all the time. The same thing will happen if the relay contacts stick closed, but that won't harm the ECM like shorted contacts. If you find that's the issue and a new relay doesn't fix it, chances are the ECM driver is dead and you'll need the ECM rebuilt or replaced.

[J30ZX]

There are two electrical reasons it can happen, a stuck ECCS Relay or a melted transistor in the ECM's relay driver. The reason the ECM needs to be able to turn itself on independently of the ignition key is so it can check the fuel tank and evap canister for leakage. It does that by monitoring vacuum in the fuel tank while the car is parked, a test called EONV (Engine Off Natural Vacuum). To perform it, the ECM uses an internal MOSFET transistor to activate the coil of the ECCS Relay, which in turn powers-up the other ECM systems. This "self-wakeup" will always happen when the car is idle and you aren't looking. If the ECCS Relay contacts collapse, it will usually short out the coil and melt the MOSFET into a permanent short-circuit that keeps the ECM on all the time. The same thing will happen if the relay contacts stick closed, but that won't harm the ECM like shorted contacts. If you find that's the issue and a new relay doesn't fix it, chances are the ECM driver is dead and you'll need the ECM rebuilt or replaced.

Ahh, I see.

Okay, my next question is where to get these parts.. Used ECM can get off Ebay off used cars, unless there is a way to get a "rebuilt" one, and this other relay??

Still haven't gotten it diagnosed, but. If it keeps doing that.. has turned my friend off to the car pretty well. I wonder... then of course HOW would diagnose.

I don't even know the last time/if it still does "intermittent parasitic draw" and I have to re-read a thread where someone seems to report an "updated sensor" fixed it but, yes, I do want this problem licked.

May even pick up an OEM timing belt water pump kit as well.. I thank you for your responses..

[jertapper]

Pretty sure the ECM won't tell the coils to fire if the crank sensor isn't working.
Crank sensor is easy to change. Three bolts and one electrical plug.

What's the actual problem?

What's the 9 digit code on your ecm sticker? Ex: A18-A89 K50

[J30ZX]

Pretty sure the ECM won't tell the coils to fire if the crank sensor isn't working.
Crank sensor is easy to change. Three bolts and one electrical plug.

What's the actual problem?

What's the 9 digit code on your ecm sticker? Ex: A18-A89 K50

Well it sure looks like I am revisiting this car soon....

Where can I find the ECM to tell you the code?

"Actual problem" = Car "drains the battery in about 5 hours" and won't turn back on once shut off. Some weird mystery problem that has everyone pissed off.

[jertapper]

ECM is in the passenger kickpanel behind that piece of carpeted plastic right of where the passenger's foot would be.