Help! Battery Connected Wrong, Now No Start or Power
 

okay this wat happened my car sat for about a month,(i doubt that has anything to do w./ it), i took the battery out and put it into my maxima because i sold it and it needed the battery, and i bought a battery a few days ago, and my friend decided he would go ahead and put it in while i was in my house, and he hooked it up backwards. and he told me when he went to put the negative on it, it sparked. but he still hooked it up, he checked the lights and they turned on so he thought it was right, so then he tried to start it up and nothing happened. i noticed, now that the battery is connected correctly, that the headlights don't pop up now, and my volt meter doesn't move either. and the car doesn't try to start at at all. i checked the fuses and they all looked good, so i'm worried that he may have fried my wiring harness :wallbash: could someone please help me in determining if that is what happend or if it could be somtehing else???

check to see if your getting power to other parts of your car, with a volt meter, check to see if your ecu is fried, those things run on mili-amps so it could have gone right past the fuse and destroyed the ecu, try another battery you may have just killed the battery

and finaly...dont let your frend get within 100 feet of your car....ever

bad friend.....no donut

how do i check to see if the ecu is fried??

good one about not letting my friend near the car lol

alternator fuse is almost surely blown (if not, the rectifier is probably shot.)

how could that be he said it didnt even crank? that makes no sense what so ever

well one way to check is if you open it up and its all black, then its gone the other is with volt meter but i dont no were exactly

also, try testing your starter, he may have just blown that

finnaly, your first test would be to swap a different batter (preferably your friends since he owes you big time) the battery doesnt even have to be the right one, just any to see if it will turn over, hell if it will crank

well first i'll try the battery and the starter, if that don't work i'll check ecu. thanks man, i'll be back tomorrow if this doesn't work

no problem, just let us no what happened

ecu is probably blown buddy of mine did the same thing,all it did was crank, dee dee dee. how the hell do people do that.

The alternator has diodes in it (electrical check valves) which allow the current to flow out of the alternator when it is charging. Unfortunately, they also allow current to flow through the alternator when the battery is connected backwards.

I can draw you a schematic, but I think that any further attempts on my part to explain will result in confusion (mostly on my part.)

Because of the reason above (and the short explanation below) the alternator will discharge an improperly connected battery very quickly (if the fuse doesn't blow.)

(please see attached schematic, observe that current flows in the direction that the diodes are pointing.)

https://www.rx7club.com/attachment.p...1&d=1181275629

(hopefully this works)

Tell your friend he owes you, and take it to a mechanic and have them fix it, and your friend pay for it.

Other than that, everybody else has the right idea for you to do.

It doesn't help (although not really an excuse) that Mazda put on a black rubber terminal protector on the positive side (instead of a red one.

Just to clarify...are all idiot lights inside the cabin turning on, radio, heater/fan, wipers, signals? Did you check *all* the fuses, both inside the cabin and the ones near the battery? Even if the Alt. AND ECU are bad, the car should still crank, so I wouldn't give up yet. Check voltage at the starter (the thick wire) from the battery.

Oh, just to be sure, when you say "the car doesn't try to start", do you mean the starter doesn't even turn (crank), because that's what I'm understanding it means.

Yep. Kid I know did the same thing. Fried like every fuse, his cd player, and toasted his ecu.

...but that's never caused me to hook up my battery backwards...
this really sucks, man

The first thing you should do is kick your friend in the nuts for being a fucking retard.

If he hooked up your battery backward then he most likely blew the Main Fuse (80A on S4). Check the main fuse for continuity (Ohms). A visual inspection won't always be sufficient.

The headlights work off the BTN fuse so they would still work (as you said they did at first) if the Main Fuse was blown.

What you should also do is check the battery for voltage. Hook up a multimeter to the terminals and check the voltage. 12.4v is what would be best, but things would still work if it was under that (to a point). Obviously lights and such would be dimmer, but they would still come on.

Alternator fuse?

went out to figure the problem today and i read some stuff about fuses and the only one i wasn't able to check last night was the main fuse,(because i couldn't take it out and get it into light because i didn't know about the 2 bolts lol) but i had an extra one lyin around so its all good i pop it in and connected the battery and it fired right up, but i have a bigger problem now sadly. i knew that i had a coolant leak already, so i just used water cause i've been tryin to find out where it was and don't want to waste coolant, so when i started it i got out real fast so i could look in there to see where it was leakin from and my car spit on me literally, i dunno where it came from but the water flew from the engine bay and sprayed me. lol. just wondering if anybody has experienced this before???? thinking maybe a crack in the block or busted seal or something let me know if anybody knows, or give me ideals, thanks.

oh yeah, i shut my car off as soon as it sprayed casue it also looked like smoke but it may have just been mist. just wondering if it would be dangerous, like any chance of fire starting or anything if i started it like that?

spraying coolant couldnt be the weep hole on the water pump maybe a hose, best i can come up with due to your explanation lol.

i read this whole thing and was about to tell you it was the main fuse then of course the second to last post theres the answer i was gonna write lol.

kevin.

Throttle body hoses most likely (go from rear of engine to throttle body and then around the outside of dynamic chamber, through BAC valve and down to front of engine.)

I sure am glad that your electrical system is ok. Coolant hoses are a lot easier to fix (I doubt that it is very difficult, because from what I know of serious coolant leaks, they all occur inside the engine.)

Am I the only one who doesn't let ANYBODY near my car? I don't even let my WIFE near my car.... let alone a dumbass friend. There are VERY few friends I would trust to drive my car, let alone pop the hood.

Anyways.. Sounds like you really hosed yourself man.

Isn't the BTN fuse fed by the main fuse?



The one time I've ever seen this done on a car (wasn't an RX-7.. it was a camry), it fried the ECU, but that was it... a quick trip to the scrap yard and a couple minutes later it was running again.... However, his blinkers blinked twice as fast from then on.... but thats just a cool side-effect. :)








EDIT: ^^ Ignore. :) Glad you figured it out.

Tie the famous friend to the bumper frame, start the car, and let him find out where the leak is coming from (I'd bet it's a hose) with his hands tied behind his back. Keep an eye on the coolant temp inside. Never let the engine overheat (anything over where the gauge usually has sat in the past).

You can also have the system pressure tested at a shop. They can even put a dye that can show leaks in ultraviolet light, although if it's spraying, your friend will find the leak soon. I bet you think I'm kidding...

Micaheli: No, you're not the only one. My wife doesn't want to drive my car - she just knows better. My buddy with another second gen. sometimes helps with repairs.

Yeah, regardless make your friend pay for it. If he doesn't, he ain't no friend. If he doesn't, make him.

Also, try 2 of these:
http://www.allelectronics.com/cgi-bi...ECTIFIER_.html

Wire them in parallel to get 80 amps. Don't worry, the pair will handle more than 80 amps for short periods of time, like when you start your car. If your battery is ever connected backwards, they'll stop your battery from putting out any power.

It's definately your friend's fault, but I still don't know why Mazda and other auto-makers don't install fail-safes/stainless bolts/etc./etc. on everything (not just battery). Altogether they might add a couple hundred to the price of the car, but they'd prevent so many problems. The only fail-safe I know of right now is the 2 independant brake cylinders so only half of your brakes can fail at any given time. And I'm sure that's only there because it's required by law.

The ecu should be ok, but the main fuse is probably fried.

EDIT: Nevermind

if it cranks and no spark, ecu