I'm thinking about switching to a one-wire alternator on the crx to simplify the car some more but wonder if I will encounter any problems with not having the ECU send (or get) signals from the alt while the car is running. I'm not familiar enough with the exact control scheme when it comes to what the stock Honda ECU does when it comes to the alternator. Does anyone here run a one-wire alternator or know if I would have problems running one? I'm about to rebuild one and this is one of the options I am given by my alternator guy.

FWIW the car is a 91 CRX HF converted to OBD1 running a P28 with a basic all motor setup. I tuned it using Crome Pro. So far it's run 12.0@110 but we haven't gotten a good run out of it since the alt took a crap lol. Hoping to get some 11 sec passes during the Houston IFO.

thanks

Mike

 

The ECU just sends a low charge output. You can disable it on a stock alt and do the same thing. You just have to power the alt with the blk/yel or run a one wire alt.

 

thanks for the info. so there shouldn't be any problems running a one-wire?

 

Out of the 4 wires going too the ALt, you just need a 12v going too it to turn it on?

 

I only had one wire going to the alternator. It does simplify it. Can't tell you the color because it was a custom harness.

 

That is true.

 

i run one on my car idles at like high 13's and stays at a steady 14.5 at full throttle

 

are you still on ECU or a standalone?

 

aem

 

would this only be an option if you had a standalone or could hondata users do this also? seems like the other wires are there for some reason.....

 

The other wires tell the ecu the voltage its putting out I belive..

 

black and yel wire needs power, rest is for dash dummy light. cut them off.

 

Two of them are for the dummy lights, the other is a low/high charge circuit. You can remove all of them BESIDES the Black/yellow wire. It needs that to charge the battery. No 12v going to the black/yellow wire, not charging alt.

 

i'm kinda in the same boat... So you need the plug but only the black yellow wire and just a main power?

 

Correct.

 

I only run the blk/yel wire with my S300. No issues at all.

 

what are the benefits of running ONE wire?

 

Less wires to run and no point in running unneeded wires on some of these standalone ecus since they are logging voltage.

edit: logging was the wrong term, i meant to say it like what tepid is saying.

 

How does it log voltage if you cut those wires off? I could have sworn one of the wires tells the ecu the voltage. If not where are you getting the data for voltage? Does the ecu read it elsewhere?

 

I thought the ECU reads input voltage to the ECU itself. It's onboard measurement.

 

OBD1 ECUs (honda) reads the voltage from the power voltage inputs to the ECU (A25).

 

keeps the voltage in the "system" steady.

in a factory vehicle the alternator will go into low mode and run the vehicle at around 12.5-13 volts when there arent a whole lot of accessories on that will pull much current

when the A/C, rad fan, high beams...etc are on it will go into HIGH mode 14 - 14.5 volts to supply more voltage to these accessories to keep the current in the circuits down.

 

thanks for the info guys. I'll post my results once I am done with it.

 

so it will always keep the voltage @ 14-14.5 volts once the car is started with only the blk/yel wire connect which is signal correct?

 

I believe it defaults to the "high" with no feedback to the alt. I get 14.5vdc out of mine with just the one wire.