Rep Power: 0

Hi all - first post...

2002 Civic EX, 94.5K miles, I only drive this car to/from work approx 12 miles each way, literally only about 120 miles per week.

My alternator cuts out at random times. I have a voltmeter plugged into my cigarette lighter at all times. When I start up the car, it reads ~13.5 - 14.5 volts usually. Randomly (sometimes while idling, sometimes while going 70 on the interstate, sometimes uphill, sometimes down, sometimes level, raining, sunny, hot, cold, no discernible pattern) the alternator will cut out, the battery light on the dash will flicker, and my voltmeter will read less than 12 volts. Just as randomly it will return to 14 volts.

I took it up to O'Reilley and used their code reader. P1298 (high voltage into ELD). I have replaced the alternator, the belt, the battery, the battery cable terminals, and the ELD. I have inspected most all of the wiring (not that there is much). I have checked all of the fuses and none are bad. I simply cannot find the source of this problem and it's driving me nuts.

Sometimes I go two days without any issue. Sometimes I go 2 minutes without any issue. It's very nerve wracking on the days that it cuts out and I'm stuck in bad traffic. I usually turn off all possible accessories (except headlights if it's dark) and get home.

I haven't yet had the car die in traffic. I've started to hook the battery up to a Battery Tender Plus at night to recharge it to get me through the next day. I recognize that I might end up killing this battery but I really want to solve this issue before I do.

This was going on very rarely a few months back but has become more and more of a problem as time goes on. Early on I could flip on a bunch of accessories and bring it right back to 14. Now it really won't respond.

I suspect a worn/bare wire somewhere rubbing against the chassis that I haven't found yet.

Any hints? Thanks in advance.

 
Rep Power: 0

Have you replaced the grounding strap that goes from the engine to the chassis right above the radiator? Honda doesn't wrap them at all. I had to replace mine. When I got the new one I put heatshrink from end to end so it wouldn't corrode like the last one. I also replaced the negative battery cable which grounds to the chassis on the wheel well and then to the transmission.

 
Rep Power: 308

Your eld will take the voltage all over the place (sometimes even with a load applied)

The charge light is a good clue though.

I would possibly look at the connections to the back of the alternator, remove clean and reconnect output terminal and remove and reseat connector.
And also check the smaller wire that ties into + battery terminal coming from alternator output.

 
Rep Power: 313

Also check all your grounds in the engine bay and make sure they are making a solid connection.

 
Rep Power: 0

I would say make sure that you check and clean every electrical connection that has to do with the alternator in the engine bay. Could be just a lot of corrosion and dirt build up.

 
Rep Power: 0

So I'm just posting because I believe this issue is now resolved.

Last weekend I gave up searching and took it to the dealership. After 2 days of testing all they achieved was killing my battery. I told them it would stop charging randomly and they shouldn't run it excessively, but they felt like it would be a good idea to let it idle in the lot for a while. Of course, it died.

They did give me a battery from a used car which I felt was fair because I'd been slowly killing the one I had anyway. So after a $100 diagnostic fee, a new used battery, and no solution, I took it home.

This past Friday I made a resolution. I'd go ahead and replace the alternator again and if it didn't fix it, I'd get rid of the damned thing and buy a new car. Turns out the new alternator did the trick. Ending up costing my nothing but my Saturday morning because the alternator I had already purchased had a warranty.

I've driven it a total of about 40 miles so far and have had no issues. Last week I was having issues every time I drove anywhere after about 4 or 5 miles.

Lesson? New alternators can crap out too.

 
Rep Power: 812

its true alternators can take a dump, but more likely there is a reason for it. most alternators are not designed to work full time or they will burn up in a month or less. anything that causes the alternator to work non stop can cause it to fail like a bad battery, something that drains the battery when it shouldnt like a leaky relay or aftermarket device, etc. can be hard to figure out but if this new alt goes bad, then you know its a bigger problem. have you checked the amp draw when the car is turned off?

 
Rep Power: 188

Modern cars (at least 6th gen Civics do) have technology on them to save gas by disabling(reducing to trickle charging?) the alternator when it thinks keeping the battery at 14V is not necessary. You'd see your voltmeter go from about 14.20 to 12.3 give or take.
Maybe that technology didn't recognize the load on your battery? Anyway glad its working for you now.


PS: My hi-out alternator was powering a 8K BTU window air conditioner shoved between my folded down back seat and the trunk, powered by my alternator all summer. Still running strong. On hot days the AC compressor in the window air conditioner would stall (because of the pressure)and soon start to smoke though.. but my 160A alternator didn't seem to mind full-field. Made my car sound a bit like an electric car with the whine.