[I'm3rd]

My '94 Alty has 193K miles, is clean, good paint, no rust, etc, and in very good shape overall, but has recently developed a bad problem. It began about 5 months ago when the engine started cutting off as I was driving at highway speed and after a couple of miles it quit and the battery wouldn't turn over the engine. I got a ride home and came back with a battery out of my truck and it started and ran fine to a shop I use about 10 miles away. They checked it out and said the alternator was bad and replaced it with a NAPA rebuilt. Then a month or so ago it did the same thing only at night 35 miles from home. I had it towed to the same shop. They said the alternator checked out good but the battery was bad and put in a new one. A week later same thing, engine cut off on interstate highway 70 miles from home and wouldn't restart. I had a battery in the trunk that I had taken out of my truck just in case and when I put it in the car started and ran good all the way back home where I recharged the new battery. Then a week later it quit again 5 miles from home and the new battery was dead again. It had a new, not rebuilt, distributor put in about 1-1/2 years ago and the shop now says everything electrical and electronic checks out OK on their SUN diagnostic machine and they don't know what's wrong. Another mechanic I talked to said the ecu computer could be bad and the SUN machine wouldn't show it. Does that sound reasonable? I can get a remanufactured ecu installed for about $300 but I'm now wondering if that doesn't fix it is worth it to keep on trying to find the problem by eliminating one possible cause at a time. I ran a for sale ad on Craig's list telling about the problem and was offered $500 by a guy who wants it for parts. I haven't taken the offer yet but I am tempted.

 

[kevins1995]

why not get an ECU from ebay and install it yourself it's really not that complex just got to know where to find it (most likely by the steering column)
Good Luck.

 

[Altima SSS]

why not get an ECU from ebay and install it yourself it's really not that complex just got to know where to find it (most likely by the steering column)
Good Luck.

The ECU on a 94 is located under the dash on the floor in front of the center console.

 

[jserrano]

Sounds like something is overloading the charging system and the battery is getting heavily discharge in the process. You can pick up a battery tester that plugs into the cigarette light and gives you a readout of the battery voltage. Drive around until you start to see the battery voltage read 12.0 and lower. That is when you know the battery is going south on you. It probably is going to take a number of tests to isolate what is wrong but this is a good start to confirm the issue.

 

[Handyman2005]

Any automotive electrical system needs absolutely clean and mechanically sould connections EVERYWHERE!!
This could be a bad negative connection that is contracting or expanding and breaking the connection somewhere . I would check each wire from the battery. I have seen battery cables rotted thru INSIDE the insulation far behind the battery connector. If any connection looks suspect- FIX IT!!