Was told the computer was bad in my nissan. got the computer out and it smells burnt, could that be the problem of it not wanting to start and battery loses charge??

That may cause the engine not to start. Can you access the CEL codes? If you can there are codes bad ECU.

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If that is the case then yes that would cause the car not to start. Computer Box is the brain of the vehicle.

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I think you identified the problem, loose alternator wires. They caused spikes to the computer, voltage regulator, and other controllers. Pull the battery out, take it to a parts store to have them test it over night. Replace if needed, then repair your alternator wires, and use die electric grease on them to keep them from corroding, and it keeps out moisture. Then with the battery out, get an ohm meter (voltage tester with ohm meter about $10) then check from your negative and battery post back to the alternator wires there should be only one wire from each side of the test that test more then 0.000 there should be a wire that connects straight from the battery to the alternator wire, and one that goes from there to the negative side when testing that circuit. If your alternator has an internal voltage regulator you may need to replace it as well. Now you will have to either keep testing your electrical to make sure everything else is ok. You will have to invest in a repair manual with a complete wiring diagram, and a few jumper wires (extensions with clamp connections and one with a probe connector. Or you can assume that it was just the one loose connection. Also after replacing your main computer you may find that your ICM is also fried, so just go ahead and remove and take it to a national parts store they have the equipment to test them. If needed replace along with the ECM, ICM, ALTERNATOR, BATTERY. Good luck, let us know how it turns out, and hope some of this helps ya.

The codes your computer puts out are just like pain signals your brain sends out. When you have pains you go to a dr to get a diagnosis, same with your car. Problem is though the fixes may end up being cost prohibitive.

Ask your mechanic put another ecu in the vehicle and then check the vehicle again and see if more codes register. If they don't then most likely just your ecu which is a cheap fix compared to other options. If it registers more or the same codes then your car is in a bit of trouble. ECU's often smell burned which isn't the case, sometimes the capacitors leak and drop their internals on the board that has a burned smell.

As with most of the solutions, yes, you need to find out what caused it to burn out,the usual cause of anything electrical frying, is.drawing to much curent,overload, faulty conections/wireing/components so you realy need to have the full system tested,before u get a replacement

Does it start and run? Does it start with a boost or jump? If it does, forget the computer and look in to your starting?charging system. Please advise.Battery losing charge can definetly be a faulty pcm, or a draw, or an old crappy battery. Start at the easiest thing. Without knowing exactly what your symptoms are, and who told you your pcm was bad, and how they diagnosed that, I can't tell you much. Please get back to me with these details and we'll figure it out for sure. Never jump to conclusions. Oh and by the way, pcms do give off a bit of an odor sometimes and can stil be just fine. Basics first, pcms are usually the last resort!

In the early years of the b16 model sentra which is what you have , nissan had a campaign to remove the ECM/ computer box foam. inside of the computer box are 2 pieces of foam. each is attached by glue that nissan used to keep them in place on the computer case/cover. however the glue was very accidic as far as fumes go and it would damage the computer / ECM, pretty much destroying it/ eating the circuit board inside of it. nissan had us remove the foam from ECM/computer box. if you still have the foam inthere now, your comuter is most likely out of commission. if it smells burned, than open it up/remove the screws that keep it closed. 4 phillips head screws keep the covers together. remove those so you can see the inside circuit board and check it closely for burned components.i have replaced ECM's in sentras and i have seen them fail. if you are going to get a used one, you will need the ECM part number which starts with number like 23710-XXXXX . the XXXXX is the other portion of part number depending on stuff that the car has such as cruise control, auto trans or 5 speed, etc. its critical that you find the right ECM / computer for your car by part number match or the car may not run. and then you going to have to have your keys registered fot the used ECM/computer also.
sometimes computer burn up because of some circuit failure, causing a high voltage on certain drivers in ECM resulting in burning them up.

If it smells burnt,it will stop your injectors, the timing "when" & which one to inject fuel into the cylinders. The BIGGEST thing you need to do is "backtrack" where & why it burned.

Hello! Yes, Since the PCM is in charge of engine controls...Main point to consider is WHY did it burn? Check the negative battery post to are metal chassis ground and engine block to negative battery post with an ohmmeter set on X10 or x100...should be zero...send results...Guru...saatler.

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Yes that certainly can be the problem. I think that you need to also isolate the cause of that problem so that it doesn't happen again. It could have been a single incident such as receiving an improper jump-start, a gross electrical problem or the computer chassis got exposed to the environment, i.e.; wet or dirty.
You will likely be able to find a valid replacement for it at a junkyard. Search for the same vehicle model, year and engine. Your best choice will be one that is clean, the computer chassis is completely assembled with no large dents and still connected to the car electrical. It likely will work and cost you a small fraction of a new one to perform the same functions.

Computer Could definitely Be your problem,When you buy a new one take the old one with you or they will charge you a core charge

There are plenty of issues why car won't start the following: Computer box not working it doesn't produce the desire pulse to operate your injector valve and the firing sequence of your spark plug. In some case you can start your engine if fuel system is dirty it clogged the entry of the fuel, Your battery losses because you use it to start the engine so the battery drain. Let your battery manually charge. In some battery there an indicator that it is fully charge. If not charging replace your battery. In your computer box if your smells something burn. Check first the connectors have some burn. This happened when the contact loss then this will produce heat and slowly the connector melt down.

Yes , if you smelled the ECU to be burned then it is confirmed that the master control- the brain- of your car is dead. There are few options to repair unless it is a power related issue and which can be checked only after removing. If not replacement is the only option.Before/after replacing please check electrical system, check the rectification/regulation to be correct as the reason for the burnt out also must be checked out .

Of course, lets think of this way instead. Say you open your computer that you are on, and you smell something that smells like it may burnt, but the computer still works now and then. A computer technician could look at it, and tell you what needs to be changed out in order for your home computer to work perfectly again. Same thing goes for your car's "brain", it may start every once in a while, but because it is the "brain" of your car, this would cause it to not want to start sometimes and possibly not want to hold a charge.

There is more likely a hidden cause that caused the computer or eprom to burn up internally. What did the voltage check at the battery show, was it charging good or over charging? If it was overcharging then the voltage regulator may be bad in the altenator cause an over current condition on the computer causing it to burn. This needs to be checked thouroughly before installing another computer or it could also get fried. The computer burning up is uncommon but it does happen and if it is shorted internally then you could have a battery drain and the car wouldn't start. Get the electriacl system checked by a qualified mechanic. It won't be cheap but neither is replacing computers.

When the computer goes bad on a computer controlled engine, it can MOST DEFINITELY cause the engine to not start. Now, the battery draining thing is another issue. The computer COULD becausing the battery to drain if it is internally shorted, however, the charging system on your sentra is not controlled by the engine computer, so it cannot cause the charging system to not work - other than the fact that the engine has to be running for the battery to charge.

If the computer is "burnt" there is a reason for it. I would not plug a new computer into that car until I found and corrected the reason that the computer burned. There HAS to be a short circuit somewhere or the battery got hooked up backwards or something. I would recommend having the car checked out by an electrical specialist before doing ANYTHING else - otherwise you could be spending money for a new computer only to have to spend the same money a SECOND time after it frys the NEW computer.

A bad computer could easily be the problem with the car not starting. You didn't mention any check engine lights. A short could be the cause for both destroying the car's computer and the battery not charging. I like to use an electrical specialist for diagnosing wiring issues over the dealership. Some dealerships would sell you another computer, charge your battery (or sell you a new one) and send you on your way. A short would put you back to square one with a failing battery and possibly another bad computer.

Yes it can be the problem. The cars's computer is the brain of the car which controls the working of each and every part of your car.