I was driving my 2003 350Z in some very heavy rain a month ago. A few hours later I was driving and the car suddenly lurched and lost complete power, not even the interior light would light. I disconnected the negative battery cable for 10 mins and it restarted fine. Got a block down the road and it completely died again. Repeated disconnecting the battery for 20 mins and it drove normal again back to work. After work, I jumped the battery for ten mins to charge it up and got 30 mins before it completely died again.

Tried the car last weekend after a few weeks of drying out and it started fine but suddenly died after 22 mins of idling in the driveway on a warm day. The battery voltage is about 12.6 and alternator at 14.5. Battery, alternator and new starter all previously tested good at O'reillys.

Seems like either an intermittent loss of battery ground, intermittent bad alternator or flakey IPDM. Its original alternator with 215K miles on it and a two or three year old battery. The car always seems to restart if either the battery is given a break to come back up after heavy loads without the alternator charging it, or perhaps whatever fault tells all the BCM/ECM/IPDM to shutdown everything, goes away after the battery is disconnected and the fault clears then allows the car to run for a while. There are no OBD codes or engine light on the car.

A year and a half ago a shaddy dealer told me the IPDM was bad but I've driven it for 15K without any issues up until now. Only strange fault I have is that the parking/clearance lights occasionally come on by themselves after the keys are out and light switch off. I've pulled the fuse and suspect a bad tail light relay stuck on. Cause I pull the fuse often, I usually have the cover off the IPDM which could account for water getting in it that one day except it still dies even a month later. Other anomaly was related to a low battery in the key fob that similarly cause the car to occasionally completely have no power after locking it with the fob.

So I'm leaning towards replacing the IPDM with a used unit. Question I have is there only one model number for a 2003 Z with manual transmission? The car is a Track model with VDC and tire pressure monitoring - CAN type 7. The dealer just goes by VIN number and can't tell me if there's different IPDMs depending on these options. Anywhere to get an IPDM other than ebay?

Thanks for your help

Can't imagine why one would ask for (and get) the trouble that comes with leaving the IPDM open to the elements.

Past that, first paragraph sounds like alt not charging and simply trying to run car repeatedly with a dead battery which can further fry an alt. Jumping a battery for ten minutes is NOT charging one up at all. Or more self induced issue.

'Previously tested good' doesn't mean spit if the parts cannot pass that NOW. Batteries run down to dead typically can maybe start and run a car but only for minutes. No alt output to keep it going. All batteries pretty much revive some voltage as they sit unless 100% dead shorted out.

It's NOT the water in electronics that kills them, pure water does not conduct electricity. It is the TRASH the water brings with it that does the damage and the water evaporates to leave the dirt behind and firmly fixed to short parts out. Why flood cars continue to give issues years later, the dirt in electrics is set to create shorting tracks and then they carbon up to become firm shorts like in a distributor cap.

Alt may now be dead (they can repeat test as good and not be, I used to do that too, I rebuild my own) and if one does not know whether the battery is 2 or 3 years old I submit that likely it is older and where most of the discussions went when I used to force answers out of people on things like that.

Not trying to be mean at all, simply the reality of it.

Thanks for your feedback amc49. My car started fine today so I think the battery's still good and the alternator still putting out 14.5 volts. I got about 1/2 mile down the road and it completely died again at low near idle rpms. Took a few hours to clear whatever computer glitch and got the car restarted, headed to O'reilly and it died again while idling. Got it restarted after disconnecting the battery for 15 mins to clear the "lock out" of all electrical power.

I'm wondering if it's a combination of faulty IPDM and either faulty camshaft/crankshaft sensor or clogged fuel filter. When I looked up replacement fuel filters nothing came up. Is it only a strainer on the pump in the gas tank?

Will a faulty camshaft/crankshaft sensor return a code and turn on the engine service light? I get complete power failure when this happens, no VDC/Traction Control lights whatsoever.

A complete power fail is something beyond any codes or normal behavior, it says something wrong with a major electrical supplying part.

A clogged fuel filter does not reset by resetting the computer.

Loadtest the battery to make sure there is nothing wrong there first. There is no such thing as a 'lockout' of electrical power. Alt at 14.5 volts could be signalling having to charge bad battery.

If the IPDM got good and wet then you likely shorted a power supply to ECM relay that then goes in minutes. You won't be fixing anything until the IPDM issue gets taken care of. THe assumption of course being the problem never showed up until it got wet. Screams what is wrong.