hello peoples, new to the forum, but not new to the honda scene. just purchased a 91 crx dx for my son a couple months ago. he's going to be getting his DL here in a couple months so we have this "father/son" project going on in hopes that he will better appreciate and take care of this crx if i make him put so wrench time in it. i have been driving it mostly for my 120 mile round trip commute to work everyday, (35+ mpgs and im lovin it compared to my pick up), and i have this recurring problem with alternator voltage spiking and frying itself. im talking 18-19 volt spikes with everything running. a/c, high beams, blower on full blast, radio on, rear defroster, wipers, i mean the maximum voltage draw this car could have and the volts never dropped. it seems to always have these spikes on the highway 70-80 mph. i've gone thru 3 alternators in the past 2 months (thank god for lifetime warranties) and i am about to install #4 today. any ideas what is causing this? it seems also to be also be alot move temperamental when its raining out. brand new battery, i checked all the ground wires i could see and they all checked out with my volt meter.. any help or info would be grealty appreciated..

 

stop buying remans from parts stores. most likely you have an inferior reman. purchase a NEW piece from your favorite parts retailer. at least then you will have a definite good piece. this will make troubleshooting much easier, if in fact there is a problem.
Regards
Dave

 

Sounds like a bad voltage regulator or rectifier. So it's the alternators.

 

the first one i purchased was a reman, but after that one quit i told them i wanted to go with a new one. the last 2 were brand new. one was a Denso, the latest one was a Bosch, so thats 3 different brands with the same exact problem. im leaning more towards the problem is something in the crx. i keep hearing about some ELD or something of the sort that regulates the voltage output of the alternator in these cars but have never gotten a straight forward answer about its location or how works exactly, but with this last alternator someone told me to unplug the pigtail from the back of the alternator with just the battery cable connected and the alternator should begin to regulate itself in essence because it had its own internal regulator. well the only difference i saw when doing that is when i start the car the volts remained at 12.1 until i actually revved the engine or started driving. it would still surge and spike as i was driving...i will upload a video link today when i go out on my lunch break. i installed another one late last night and drove to work today with the same issue...

 

About 8/10 alternators that I remove and disassemble have a brush that is not right for the application, or is not clocked correctly.

Check resistance in the charge line from the alternator to the fuse box. Also test the battery. Batteries that do not accept a charge at 14v will increase the alternator voltage until it does.

The ELD is a hall sensor mounted on the alternator wire/primary battery feed. This detects the current draw on the battery and will increase rotor field voltage to maintain the battery's state of charge.

Any modifications to the car electronically? Stereo? etc.

 

we had a 200 watt amp and a 10" subwoofer installed prior to all these electrical problems, buti have since disconnected them to rule them out as the problem. i haven't reinstalled them since. other than that, the car is bone stock..

 

do you have any pics of this ELD and its exact location so i know what im looking for??

 

Those would hardly be a problem so long as they work as designed.

The sensor is built into the fuse panel under the hood and runs off of one side of the battery fuse. As current is drawn out of the battery, this sensor will detect the discharge, increasing the alternator output to match what is drawn out, to maintain state of charge.

Even though the amp is 200 watts, using a 500millifarad to 1 farad capacitor will smooth most distortions caused by the amp drawing instant power. In most cases, too much capacitance is not a problem (inrush current would be though lol).