Crossed Battery Terminals - Car Won't Start

[Superluminal]

I was in a hurry, and apparently the new battery I installed had the + and - terminals opposite what the old battery had. I should have checked beforehand, but like an idiot, I didn't realize my mistake until I tried to turn over the car and found out I had no power.

:picardfp:

I corrected my mistake, checked all the fuses in the engine bay and found that the alternator fuse (75A) was blown. I replaced that fuse and restored full power to my car (everything electrical works), but the car still won't fire up. The starter just cranks and cranks. Is there another fuse I'm missing or did I fuck something up really bad (which I doubt since the car should have fuses for just the reason)?

'90 240SX
Redtop SR

UPDATE 2/9/2013:

Well it's the ignitor. Friend brought over his ignitor chip and ECU. Put the ECU in first, didn't start. Put the ignitor chip in fired right up. Put my ECU in, fired right up. Ignitor chip is fried. Anyone selling one?

[slider2828]

Could be ecu.... My friend did that to my car.....

Try an ECU or trace down the problem, but the easiest solution is get a new ECU first.

[shiftdrift]

check all fuses first.

[Nissansota240]

Does the starter just spin or do you mean the motor actually cranks?

[Superluminal]

Does the starter just spin or do you mean the motor actually cranks?

Yes, the motor is actually cranking over, just not firing up. Starter is working fine.

[Superluminal]

Could be ecu.... My friend did that to my car.....

Try an ECU or trace down the problem, but the easiest solution is get a new ECU first.

Easy if you have a stock ECU, mine is chipped and tuned. I will pull the ECU shortly to see if any leads got damaged. Isn't there a fuse that protects the ECU in the event of an electrical overload? The alternator had one, and that fuse blew, but I replaced it.

[Superluminal]

check all fuses first.

I checked the main fuse box in the engine bay and they are all intact (including the alternator fuse I replaced).

[zerodameaon]

Easy if you have a stock ECU, mine is chipped and tuned. I will pull the ECU shortly to see if any leads got damaged. Isn't there a fuse that protects the ECU in the event of an electrical overload? The alternator had one, and that fuse blew, but I replaced it.

Chipped and tuned does not mean you can't put a stock one in just to see if its the ECU.

[oni jake]

I checked the main fuse box in the engine bay and they are all intact (including the alternator fuse I replaced).

Adding to this: have you checked the main fuses under the driver's side kick panel? It doesn't sound like you did.

[bussitcustoms]

Chipped and tuned does not mean you can't put a stock one in just to see if its the ECU.

x2- a stock ecu will still start the car. Don't go driving it like that, but it will allow you to eliminate that as a cause if it isn't the issue.

[Superluminal]

Adding to this: have you checked the main fuses under the driver's side kick panel? It doesn't sound like you did.

I don't think there is anything relative in the kick panel fuse box that would cause the car not to start. Isn't that for accessories? I'll take a look in the morning.

[rat240]

i did this before and my 75 amp alt fuse was out

[ashtonroche]

Yep, check all the other fuses, main ignition fuse, eng contr fuse which supplies power to the ecu, the other fuses inside the car as there is the constant battery power for the ecu in there under eng control which is also the supply for the injectors.

If all your electrical checks out then more than likely you fried the ecu. Doesnt take long. But the fusible links similar to the 75 amp alternator fuse but smaller, are hard to tell sometimes when they are blown. They will look pretty much intact until you remove it and shake it a bit and/or test it.

[ashtonroche]

Are you getting a fuel pump prime? if not, then its safe to say either your ecu isnt getting power or you fried it.

[oni jake]

I don't think there is anything relative in the kick panel fuse box that would cause the car not to start. Isn't that for accessories? I'll take a look in the morning.

Ya man, as the other guys said above me, that's where the fuses are at the ECU and other engine sensors.

Definitely tell us if the fuel pump primes or not if the fuses check out and you still have problems.

Frying your ECU by connecting the battery posts opposite is hard to do, but definitely possible. I just wouldn't throw all my eggs in that basket just yet.

[Superluminal]

Are you getting a fuel pump prime? if not, then its safe to say either your ecu isnt getting power or you fried it.

The fuel pump primes, but it's jumped with a wire so it stays on all the time when the key is turned on.

[Superluminal]

i did this before and my 75 amp alt fuse was out

Just replaced this. It restored power to the car, but the engine won't fire up.

[Superluminal]

UPDATE:

Just checked the ECU, there is a solid red light when the key is turned on. It is getting fuel, the ECU is getting power... my guess is something ignition related.

[thisisnotphil1]

Its very possible the ecu is crispy. But in the off chance that its alright, Make sure youre getting injector pulse. If you arent, get a voltage meter and check the crank sensor and cam angle sensor for correct voltage. No injector pulse, no start.

[Superluminal]

Its very possible the ecu is crispy. But in the off chance that its alright, Make sure youre getting injector pulse. If you arent, get a voltage meter and check the crank sensor and cam angle sensor for correct voltage. No injector pulse, no start.

Can the ECU still be bad if the light shows on it?

[ashtonroche]

Yes, you could have fried the injector drivers or ignition drivers in the ecu. Those are the weakest links inside the ecu and will be the first things to go if something is crossed or shorted.

Again check for power at the coils and injectors. If you have that, your fuses are good and your obviously getting power to the ecu. But the ecu might not be triggering the injectors or coils because of you frying it. Im gonna guess its the injector drivers because they are the only thing that remain constant hot power wise on the motor. A crossed terminal will backfeed the ecu through that spot. Your ignition power is only on in the ignition on position so unless you had the key in the on position when you hooked the battery up wrong that circuit should be ok because there was no way for it to complete.

My guess is you burnt the ecu's injector driver side and whatever else is powered by the battery constant. You can get away with a slight touch most of the time but if it was on there for any decent length of time, you pretty much are probably screwed.

[thisisnotphil1]

Yes, you could have fried the injector drivers or ignition drivers in the ecu. Those are the weakest links inside the ecu and will be the first things to go if something is crossed or shorted.

Again check for power at the coils and injectors. If you have that, your fuses are good and your obviously getting power to the ecu. But the ecu might not be triggering the injectors or coils because of you frying it. Im gonna guess its the injector drivers because they are the only thing that remain constant hot power wise on the motor. A crossed terminal will backfeed the ecu through that spot. Your ignition power is only on in the ignition on position so unless you had the key in the on position when you hooked the battery up wrong that circuit should be ok because there was no way for it to complete.

My guess is you burnt the ecu's injector driver side and whatever else is powered by the battery constant. You can get away with a slight touch most of the time but if it was on there for any decent length of time, you pretty much are probably screwed.

+1 preachhhhhh :faint:

I know you learned your lesson now about taking your time with ANYTHING electrical. Always take your time

[Masa]

did this before, fried my ignitor. try swapping a KNOWN good one.

[OrangeVirus1]

you probably blew all sorts of fuses.. check all of them.

[Superluminal]

Yes, you could have fried the injector drivers or ignition drivers in the ecu. Those are the weakest links inside the ecu and will be the first things to go if something is crossed or shorted.

Again check for power at the coils and injectors. If you have that, your fuses are good and your obviously getting power to the ecu. But the ecu might not be triggering the injectors or coils because of you frying it. Im gonna guess its the injector drivers because they are the only thing that remain constant hot power wise on the motor. A crossed terminal will backfeed the ecu through that spot. Your ignition power is only on in the ignition on position so unless you had the key in the on position when you hooked the battery up wrong that circuit should be ok because there was no way for it to complete.

My guess is you burnt the ecu's injector driver side and whatever else is powered by the battery constant. You can get away with a slight touch most of the time but if it was on there for any decent length of time, you pretty much are probably screwed.

My ECU is chipped and tuned. Do you think the daughterboard is still good, assuming the ECU is fried? Also, would you be able to visibly see what fried on the ECU board upon inspection?

[Superluminal]

you probably blew all sorts of fuses.. check all of them.

I did. All fuses are good. Only had to replace the alternator fuse.

[OrangeVirus1]

one only option left. you blew the head gasket.. lol j/k

possibly killed your ecu man. Capacitors usually are meant to get current only in one direction, and getting them in a different direction can and usually kills them. you'd never be able to tell they are dead though, because technically they would still *work* but not be pumping the proper voltages anymore, and visually they would look fine.

how long were they connected wrong before you realized it? the longer the worse / more damage. you know there is enough power in that battery to literally melt wires and "weld" wires together..

<-- electrical engineering major :)

[brndck]

99% of the time, the ignitor fries.
you probably still have injectors firing, but no spark.

use a noid light to confirm this.

if you have injector pulse, but no spark, replace the ignitor and go on your way.

[Superluminal]

one only option left. you blew the head gasket.. lol j/k

possibly killed your ecu man. Capacitors usually are meant to get current only in one direction, and getting them in a different direction can and usually kills them. you'd never be able to tell they are dead though, because technically they would still *work* but not be pumping the proper voltages anymore, and visually they would look fine.

how long were they connected wrong before you realized it? the longer the worse / more damage. you know there is enough power in that battery to literally melt wires and "weld" wires together..

<-- electrical engineering major :)

Doesn't the ECU have a fuse so something like this is prevented from happening? I checked the ECCU fuse on the kickpanel and it was fine.

[OrangeVirus1]

Depends if it was enough current to blow the fuse. But probably the fuse should of blown so I'd say 90% chance your ECU is good

[Superluminal]

Depends if it was enough current to blow the fuse. But probably the fuse should of blown so I'd say 90% chance your ECU is good

It was only a 10A in there, and it didn't blow, yet it blew out my 75A alternator fuse. So I should try an ignitor chip first I presume? Where in the hell am I going to get one of those?

[ashtonroche]

Like I said, just do your simple checks. Check if the injectors are firing and if the coils are firing. If your getting injectors firing then like they said either the ignitor fried or the ecu is done for.

If the ecu fried the daughterboard would probably still be good. All the daughterboard really does is hold reconfigured settings. All the drivers and stuff are on the motherboard.

[Driftwire]

Listen man, We understand your ECU is chipped and tuned. Quit beating around the bush. go get a known working ecu plug it in and see if it fires up but dont run the car hard or anything with it. If it fires than start worrying about if the Daughterboard is good.

[Croustibat]

Fuses are supposed to protect against overload, not against reverse polarity.

Now try another ECU...

[Superluminal]

Listen man, We understand your ECU is chipped and tuned. Quit beating around the bush. go get a known working ecu plug it in and see if it fires up but dont run the car hard or anything with it. If it fires than start worrying about if the Daughterboard is good.

Working on it. :cool:

[slider2828]

Yeah there are only 2 things to replace, ecu and ignitor... other than that, its a fried wiring loom but doubt it. Good luck man! I know its frustrating, but it boils down to those 2 things....

[Superluminal]

Yeah there are only 2 things to replace, ecu and ignitor... other than that, its a fried wiring loom but doubt it. Good luck man! I know its frustrating, but it boils down to those 2 things....

I literally want to strangle myself. To think I could do an engine swap yet do something as stupid as this just makes me reevaluate my sanity.

My friend who lives on the other side of the state is going to loan me his ECU temporarily, since his car doesn't run.

[slider2828]

Awesome man! Good luck. I fried my ecu while the battery was connected and messing with the mafs. It happens

[EDacIouSX]

Working on it. :cool:

smell the ecu, if it smells like something burned then it burned.. it's possible for the chipped part of the ecu to still be good

[mxexux]

Fuses don't work as well when they are on the ground side of the circuit which is what you essentially did when you hooked up the battery in reverse polarity.

[Superluminal]

Well it's the ignitor. Friend brought over his ignitor chip and ECU. Put the ECU in first, didn't start. Put the ignitor chip in fired right up. Put my ECU in, fired right up. Ignitor chip is fried. Anyone selling one?

[Rustys14]

If you can't find one just go to the junkyard and get a 92-96 q45 ignitor. Q45's are a dime a dozen so it shouldn't be too hard to find one. If I remember right the 95 and 96 q45 ignitors are plug and play while the 92-94 require some simple wiring since the plug is different. I used a 92 q45 ignitor on my old car since my swap didn't come with one and it worked great.

[bussitcustoms]

None of the q45 ignitors are plug and play (to my knowledge). They all need rewiring, but do work just fine. I have about 4 of them. If you want one, PM me.

[bussitcustoms]

This guy has one for an sr for $38 shipped

http://zilvia.net/f/sale-items/502388-sr20-parts-sale.html

[blueshark123]

None of the q45 ignitors are plug and play (to my knowledge). They all need rewiring, but do work just fine. I have about 4 of them. If you want one, PM me.



This is false some q45 have the same exact ingnitor as a sr.

http://www.ebay.com/itm/Used-1993-96-Infiniti-Q45-Ignitor-Igniton-Control-Module-22020-50F00-DIS4-04-/230924407070?pt=Motors_Car_Truck_Parts_Accessories&fits=Model%3AQ45&hash=item35c42ad11e&vxp=mtr