TheRedZed

I'm stumped. The tale of woe:

I went to Cars and Coffee and I hit lots of rain/big puddles. I got there fine, car running fine, and shut it down for about an hour. Come time to leave, it cranked but wouldn't fire - I figured wet plug wires. After a couple minutes it cranked up and I started de-fogging the windshield, idling. The AC compressor wouldn't come on, and engine coolant temp started getting hot - so I pulled out and started driving home and the temp came back down - but my volts gauge was really low - 8-10 volts. Got it home and figured the battery terminals were corroded and wet so the battery isn't charging. Typical. I replaced the negative terminal and fixed the positive (loose) and go to crank and - nothing. Voltage gauge showing like 8-10 volts until I hit the starter and then zip. So I try to charge the battery, and it won't charge or boost-start from the charger. I remove the battery and take it down to the auto parts store thinking it is shorted (not even two years old) and they get over 12V and 520 CCA by the time I get there - seems it recovered. I'm scratching my head while they put a quick charge on it. In 15 minutes it's up to new battery specs. I take it home, install it, and zoom zoom, car cranks up great and I run it for about 10 minutes, everything looks good, 14V on the gauge so alternator is good. Done, right? Nope. About an hour later, I try to start it and it's back to 8-10 volts, no crank. Since my AC hasn't been working until I start rolling, I figured the cooling fans might not be coming on, maybe a relay is stuck - nope, tested all 3 fan relays, they are good, but I confirmed the fans do not come on with AC. Car didn't get hot enough for me to check if coolant temp brought the fans on.

I guess I've got a current drain, evidently due to the rain water, something under the hood....and also something wrong but unrelated with my cooling fans..... I've got the battery disconnected now, and it seems to be recovering again, slowly.

Any ideas as to what the water would most likely short out? And to test the cooling fans, 12v on which harness pins? Other suggestions?

dkmura

iTrader: (64)

Check the IDM for any water contamination, but I think something else is up. Unless you really dunked your Z into a big puddle, it's pretty water resistant. Have you done a scan for codes?

TheRedZed

No codes thrown on the dash, should I see if the code reader finds any? I assume any codes would flash a MIL or a CEL. And yes, I did find traces of water up in the IDM when I pulled the relays. Everything wasn't soaking wet, but I found multiple drops in and around the relays.

dkmura

iTrader: (64)

No,not all codes result in a CEL. If the diagnostic system doesn't determine it will be will result in a safety or powertrain failure, it'll just put a code in memory. BTW- I misspelled the IPDM (not IDM) and if you got moisture in there, you should make every effort to completely dry it out. That's a LOT of water you went through to get water that far up into the cowl area!

TheRedZed

Hooked up the amp meter, there's a 0.6 amp drain. I'm not sure 0.6 amps would have killed my battery yesterday in an hour but it's more than it should be............maybe things are drying out. I think I'm going to open up the IPDM box again and hit it with compressed air - see if anything squirts out. If not, I'll hook up the meter again and start pulling fuses.

travlee

iTrader: (8)

Dielectric grease it if you take it out and its dry

TheRedZed

Well, my multimeter fuses are blown, can't do any current drain diagnostics. Had to order fuses online.......Wednesday is the earliest. Ugh...........

onecoolee

How did the fuse(s) blow? Usually it has a 10A fuse for current measurements. Unless you cranked the car with the meter inline with the battery, the fuse should not have blown.

0.6A is alot of draw with everything off. A weakened battery might last 30-60 mins with that kind of constant draw. If its just a cheapo meter that can be sacrificed, just use foil or a wire to bridge the fuse terminals, and get back to measuring... no sense in waiting until weds for fuses. Be sure you are on the right meter settings when measuring current too, that can cause your meter to blow fuses. It does sound like you have a short somewhere. The easiest way to find the culprit is with your meter in current mode hooked up inline to the main battery lead, start pulling fuses, 1 at a time...when the 0.6A (600mA) drops to less than 50mA, the culprit is on that fuse/circuit.... check the stereo first, if you have an aftermarket stereo, or amps, poorly grounded or faulty wiring can easily cause this. Good luck with your troubleshooting.

TheRedZed

Well I wasn't planning on getting detailed about the dumass who tried to measure battery voltage with the meter leads still plugged into the current measurement ports. A Fluke meter is smarter than that, but this one is old school.

onecoolee

Ahh yes, been there myself on that front.... don't try to do that if you end up shorting the fuse, that will fry the meter.

TheRedZed

I can easily imagine what 640 cold cranking amps would do to that poor little meter............

onecoolee

Well, the battery is capable of producing 640 CCAs, but whatever the actual current draw is at startup, is hopefully less. Either way, hooking up your meter to measure current with the probes attached to the wrong ports will surely attempt to fry it.

TheRedZed

Well who would have thought, my free multi meter from Harbor Freight measures current! The current drain is down to 100ma now. So I hooked up the battery and the car fired right up. But no cooling fans.

So, can I get some help on tracking this down? I've already tested the relays, they are good. Starting with the fuses - under the dash or under the hood? Which fuse? If it isn't the fuse, could it be the climate control is not telling the ECU to turn on the fans? Next would be to hit the fan motors with 12V? Which pins in the harness? What have most folks seen fail on these cars?

Has anyone had any luck doing this procedure to check the fans...?, look at entry #6: https://my350z.com/forum/maintenance...n-i-think.html

TheRedZed

So I tested again with my better multi meter this evening, now that I have fuses. Current starts out at 600ma and then drops to 120ma after about 10-15 seconds. Still seems like 120ma is too much drain - correct?

I also did the test I linked above - it is a valid self-test. No cooling fans but I heard the relays click. So I guess I need fans. But since the relays are open when I measure my current drain, new fans won't solve that problem

onecoolee

120ma with the key on ACC? That seems realistic, as the iinitial draw (600mA) will be higher as things turn on. I would expect the draw to be less than 50mA with the key OFF.

TheRedZed

No, 600ma dropping to 120ma just from shunting between the negative cable and the battery. No ACC or anything. I suppose the security system and a few other things draw for the first 15 seconds. But it holds at 120ma, nothing on.

onecoolee

120mA of draw would probably drain a fully charged/good battery in about 2-3 weeks. That seems a bit quick. I would think your car could sit for over a month, or even a couple months without needing to be charged to start. 120mA of parasitic draw with the key off is ALOT. Something is leaky or shorted or just plain ON when it shouldn't be. Typical parasitic draw is probably on the order of 20-50mA, especially after the electronics goto sleep, maybe 30-45 mins after a drive.

Did you isolate the circuit culprit here by pulling fuses to find out where the excess draw is coming from ???? That will be the only way to narrow this down, I think there are about 50 computers/circuit boards, that all contribute to this, in the 03-05 350Z. There should be 1 circuit that is contributing the most to your draw problem, you jsut need to find it, then go from there as far as fixing it. The audio circuit is the most likely, because alot of people don't hook up aftermarket stereo equipment properly.

TheRedZed

I haven't pull fuses yet, I just got the multimeter back into use. But yes pulling fuses is next.

So please clarify something for me - when I test, I shunt between the negative cable and the battery post. I get 600ma for 10 seconds, then down to 120ma. Should I wait longer? Maybe the 120ma is still the some circuits doing an initial charging? Should I wait for the electronics to go to sleep (~45 minutes?) for the "base" parasitic drain?

Oh, and the audio was installed perfectly - I did it! =P
Actually just a head unit, no amps or subs. This is a track car, after all!

onecoolee

It shouldn't matter whether you use the ground lead or postive lead, but I have always put the meter in line between between the + battery post and the positive battery clamp/terminal (obviously removed from the battery). This will measure the current draw out the + post.

Just a head unit, and assuming you used an install kit with connectors to factory wiring shoudl prevent any weird issues. Its when people add amps, and try to keep stock HU, etc, where bad things can happen.

I personally think that with the key off you should easily be under 120mA, even before the 45 minute wait time... but thats just a guess.

TheRedZed

Yeah, I think sitting by itself overnight with just the alarm and remote key/FOB sensing should be like 20ma or less. I guess I could open up my DD and see what milliamps it pulls......might be apples and oranges comparison tho.