ECU (w/K-Pro) went bad. Is repair/replacement available?

Hondata model coverage & ECU application questions.
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MacLotus
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ECU (w/K-Pro) went bad. Is repair/replacement available?

Post by MacLotus » Mon Jul 14, 2014 11:45 am

I believe my ECU may be damaged (according to the Honda manual), but I'm certain the K-Pro is working fine. Is it possible to send it in and have my K-Pro board swapped to a new PRB ECU board?
Ken

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Re: ECU (w/K-Pro) went bad. Is repair/replacement available?

Post by Spunkster » Mon Jul 14, 2014 1:24 pm

What exactly is the problem?

MacLotus
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Re: ECU (w/K-Pro) went bad. Is repair/replacement available?

Post by MacLotus » Mon Jul 14, 2014 2:49 pm

The portion of the ECU that controls dual-rate battery charging is not working properly. After following the Honda manual's troubleshooting procedure, it says replace ECU. New battery and alternator, plus cleaning all ground points and countless hours of troubleshooting. After sitting a day or two, start-up and battery charges fine at 14vdc+, then after 10-15 minutes stops charging... As though it shutdown.

I think I damaged the ECU by using the 'Battery Disconnect Switch' before the ignition switch. This 'race car' switch physically disconnects the battery from the car, but I've since learned that could damage the alternator (which it did) and the ECU. I had hoped it didn't, but now I'm pretty certain it did.
Ken

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Re: ECU (w/K-Pro) went bad. Is repair/replacement available?

Post by Hondata » Mon Jul 14, 2014 3:16 pm

None of the RSX era ECUs actually control the alternator voltage - they always are internally regulated (~ 14V). I'd disconnect the ALTC wire from the ECU.
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MacLotus
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Re: ECU (w/K-Pro) went bad. Is repair/replacement available?

Post by MacLotus » Mon Jul 14, 2014 5:28 pm

I disconnected the Alt C wire a while back. New Denso alternator. Voltage output measured at alternator. 12vdc IG circuit good. Charge of 14vdc output is there.... then it drops out. I've been chasing this gremlin for two years now, although I don't drive it much.

So if I understand what you're saying, the alternator will always provide an output with only the Alt IG wire and Alt B (battery charge cable) connected, although idle speed will remain constant.
Ken

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Re: ECU (w/K-Pro) went bad. Is repair/replacement available?

Post by Hondata » Mon Jul 14, 2014 8:33 pm

The alternator only needs B & IG to work. L is light, C is control, FR is field voltage (input to ECU).

I'd check that the ALTC connection is not floating to ground (which is low output mode).
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MacLotus
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Re: ECU (w/K-Pro) went bad. Is repair/replacement available?

Post by MacLotus » Tue Jul 15, 2014 9:23 am

Good idea. I'll check that out.
Ken

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Re: ECU (w/K-Pro) went bad. Is repair/replacement available?

Post by nanim0n » Sun Jul 12, 2015 7:28 am

Sorry to bring this back from the dead but I think my ecu is bad too . having fuel problems . not priming . switched my ecu into a friends car and did the same thing .

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Re: ECU (w/K-Pro) went bad. Is repair/replacement available?

Post by Spunkster » Mon Jul 13, 2015 9:35 am

Please start your own thread as it has nothing to do with this post. Follow the posting guidelines.

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