Hondata

Hello,

For a while, the S300 was running very well, then one day, it started running a little rougher. Then I noticed that the 12V signal was a little low compared to what the battery measures out at (Smanager showing me 12.7V when the battery measures out at 14.1V with the vehicle on). So I checked my thermostat ground (and all grounds that I can get to) and the inputs into the ECU and it measures out to 14.1V as well, even though Smanager is telling me 12.7V. Anyway, just 2 days ago, attempting to turn on the vehicle, it wouldn't start and the S300 had a solid red light, unable to do anything, then maybe 30 seconds later, it went green, fuel pump primed and started. It did this twice, but the second time, it stalled out on me and wouldn't start again. It wouldn't communicate through Smanager, even though it says that it is connected. I've tried this in another known good working ECU of mine and it shows the same problem. I tried my buddy's S300/P28 setup with my calibrations in it and it works just fine (voltages read fine and operates as expected). I plug mine back in and it is a solid red light.

So I leave it for a day and yesterday, I plugged it back in, and it seems to be able to start the car, but still runs a bit rough. I have the latest beta version of Smanager, so after reading a bit on the forums, I went through the erase process, loaded a brand new calibration (changed only injector size and MAP) and started it up, it starts up running ok, so I let it idle for a bit (afr ~14), but then it started to stumble, afr's still OK, but the voltage started to drop as displayed in Smanager, even though my multimeter measures out actual system voltage to be OK (14.1V), and then it stumbled and stalled out. I then tried my buddy's S300/P28 setup again and it works just fine. I put his S300 into my ECU (also a P28) and it works fine as well. Currently, the S300/P28 of mine still starts the vehicle, but it is inconsistent and I'm not comfortable driving it anywhere at the moment.

I don't have the serial number handy with me right now (I'm at work, I'll post to this thread when I get home) so, does anybody have any suggestions? It appears as though the S300 board may be the culprit.

This is a 2000 Civic Si, B16A2, P28, S300, Turbo. Prior to this happening, it was running fine for almost a year (I bought the P28 and S300 last year July 12th). So I may still be in the Warranty period.

Thanks,
Charles

What is the serial number of the s300?

My serial number is 21453.

The version of Smanager that I am using is 2.2.7.0.

Where are you measuring the voltage with the multimeter?

So, I measured the voltage while the vehicle is on, across the battery posts, the battery positive to thermostat ground (and other random ground points). On the ECU side, while plugged into the ECU, using paper clips, A25 to A24, A25 to A23, B1 to A24, and B1 to A23. I'm not sure which ones the ECU is using as their main 12V source, so I measured all of them. I haven't checked any of those to any logic grounds (since I don't know what are for).

So the voltage is reading normal everywhere but in datalogging? Is that correct?

That is correct. I also have a cigarette lighter meter that tells me voltage as well, and that reads correctly. The same issue exists with the same S300 in my other P28 ECU.

Remove the lid and measure the voltage on the pins inside the ECU across A23 and A25 and across B1 and A23.

http://www.hondata.com/help/smanager/ecuconnectors.htm

The voltage is not measured by the s300, it is a send to the s300 via a serial link from the ECU. So it is actually the ECU that is sending the voltage to the s300 and that is the value you are datalogging.

So it appears that leaving it over the weekend with the battery disconnected seems to have changed something. Everything is reading normal again in Smanager (i.e. 12V reading vs. multimeter measurement). I am still a little nervous about driving her anywhere though, any thoughts on the solid red light though? could it be related?

The battery voltage should have nothign to do with the s300 itself. All you can do is try it now and see what it is doing.