s2kuae

Guys, I have a newbie question. So my speedometer lights are flickering, tail light bulb gets busted from time to time and my audio amp goes on protect mode like forever. Obviously I have an issue with the rectifier. Planning to change the whole alternator which I will do this weekend. However, just this morning, I tried and used a multimeter on my 80ah amp battery and I was surprised to see 24V!! My multimeter is rusted and I'm not sure if the reading is accurate but my Pioneer headunit shows 13.3V to 14V. Aside from that, I'm having weird idle issues, 200 - 300 almost dying then goes back to 1000 after 2 secs on the click of the A/C and serious hesitation/stalling problems when it's hot (120F during noon time) outside plus huge power loss. No check engine light but 2 faulty codes were recorded, faulty knock sensor and secondary air pump. My question, could all these issues be related to the Rectifier?? Or is the hesitation caused by the heat outside? At night it runs fine! I have twin cat back exhaust and K&N intake tube. Any suggestions?

s2kuae

Solved this issue by buying a used complete alternator for $300. Now I have a spare Alternator with a broken Rectifier lying around. Below is a pic of it beside the D16y alternator. Damn, they look the same. Could have just bought the D16y used alternator for $50 and tried swapping the Rectifier. Left pic is the S2000 Alternator and on the right is for the D16.



Both rectifiers removed, they look exactly the same. Well Except for the location of the Terminal.



Here is the pic of the D16Y Rectifier placed on the S2000 Alternator.



And here is a pic of the S2000 alternator with the D16Y rectifier and D16Y alternator back cover on.



never actually tried it on the car itself. But it turns out that all the B series and D series rectifiers fit!

Gregg Lee

There is at least one other S2000 electrical part that is the same as some other Hondas, except for connector or wire lead length. The one I know is O2 sensor. Could be others.

Someone should make a list. Or maybe someone has?

windhund116

This maybe a regulator issue and not rectifier. But, perhaps the regulator is also inside that back plate of the alternator?

Anyhow, bad rectifier diode allows AC through. I remember that as a buzzing noise in the radio. IIRC.


Nice fix, though!

slalom44

New replacement rectifiers are pricey ($181.00 at online stores) but used alternators with good rectifiers are reasonable. I bought a used alternator on eBay for $45 delivered a while back, knowing I'd need a replacement eventually. I opened it up and found plenty of meat left on the brushes.

I'm in the process of doing a clutch job and since my alternator (and my car) has 330,000 miles on it, I decided to pull the alternator out. Replacement brush assemblies are cheap ($10 on eBay) so I just bought new brushes and I'm going to keep using the original alternator. I'll keep the eBay alternator as a spare. Fortunately I have had no rectifier problems.

BTW: The brushes I took out had no meat left on them. Another few thousand miles and I would have been stranded somewhere. If anyone is wondering how long the brushes in an S2000 alternator can last, it's around 330,000 miles.

zeroptzero

wow that is good to know, that alternator doesn't owe you a dime, lol.

Is there a way to test rectifiers on an alternator that is out of the vehicle ?. I've got a couple of alternators sitting around as spare parts, I believe one got shorted by accident when pulling it out of the vehicle (forgot to disconnect the battery first , lol).

slalom44

There are ways to check rectifiers. Check this out: http://m.youtube.com/watch?v=xgikeXt91vM&autoplay=1

zeroptzero

Thanks !

shind3

Thanks to s2kuae, his pictures, this thread, and Billman (from other threads) which gave me the courage to think about attempting the following:

At 132K miles on my 2006 S2000, I was starting to see some very mild dash flickering once the engine got heat soaked. Figured I would replace the rectifier with a new (31127-PCX-101) OEM unit. There seemed to be plenty of meat left on the spring loaded contact blocks since I had to compress them a good ~5mm to get that sub-component installed over the main alternator shaft. The bearings also seemed fine as they rotated very smoothly.

I saw an increase in measured battery voltage (through a Fluke Multimeter and Hondata Flashpro logger) from 14.2V to 14.5V after doing this.

I also measured the resistance across the rectifier at the following two points and noticed the new unit read 2.2Mohms while the old unit read 3.6Mohms. Not sure if that means anything but it is a data point.


Here's a picture of the alternator disassembled to the level needed to do this. I also had to remove the intake and throttle body to gain access.


I haven't driven the car yet, but it seems to idle fine. I'll update this post if there are any issues.

Slowcrash_101

I replaced mine 2 1/2 years ago with an eBay rectifier for $24, still flicker free.