Hondata s300 on P28 working for years then died during tune.

[TurboLS]

ECU: P28
Hondata s300 serial number: S300-0516
Vehicle: 1994 Acura Integra LS 4-DR B18B1 Non-VTEC

History: This ECU/s300 combo was tuned and powered my car for a few years without any issues. After installing a new turbo and some sensors, we were pulling the car onto the dyno when what felt like a power surge stopped the datalogging and caused the car to stall. We have since not been able to get the car to start, even though it cranks, has fuel, has spark, has compression, and is timed properly. We popped the case off of the ECU and only see the red light by the USB connector and the green light further towards the center.

The laptop detects when the car/ecu has power and allows us to click the datalog and record buttons, but no data is actually transferred. We see absolutely zero change in sensor readings which we know should change (such as the TPS sensor reading when modulating the pedal). When we click datalog, the red LED stays on most of the time while we see a periodic flicker of a green LED next to it. In our experience, the passage of data is indicated by several flashes of the green LED at much higher frequencies than what we experienced.

We tried swapping to a different, known-good ECU/s300 combo and had the same issues, leading us to believe that the failed s300 caused some issue in the harness, which is the only thing we think could cause a similar failure in the previously known-good ECU/s300 spare.

What we haven't tried is attempting to connect to either the original or spare ECU/s300 combos in a different vehicle for fear of screwing up another car's harness.

I am wondering if I can get a legitimate schematic for the s300 board so I can figure out why no data is being transmitted even though power appears to be applied to the device.

Does anyone have input?

[Spunkster]

The ECU will not damage the harness. More likely is that a wiring fault in the harness is causing the problem with the ECU. Try the ECU in a known good vehicle and if that works ok, you know you have a vehicle specific problem.

[TurboLS]

We should know more by COB today. Thanks for the confirmation on whether or not the s300 will screw up the harness.

[TurboLS]

So i guess i do have a follow up question: assuming it is the vehicle's wiring, what, aside from the Helms chapter 11 circuit checking, would you recommend looking at to debug this issue?

[Spunkster]

Look at the areas that have most recently been touched and check for problems.

[TurboLS]

OK... so we can't really explain it, but we tried several combinations of clicking update USB driver, uploading calibrations, and s300/ECU combos and what we think did the trick was that the s300 *EDIT* spare */EDIT* needed to be "reset" by plugging it into a different car.

As soon as we did that, we hooked it back up on the original car *EDIT with the original ECU */EDIT* and everything worked. Totally weird deal. Maybe gamma rays? I really can't explain it.

Since it happened during a tune during a calibration update, I can only think that the software somehow caused a glitch and latched something in the hardware which was reset by plugging into a different car. Totally weird.

Assuming the dyno tuning goes well tomorrow, we can consider the current issue "resolved w/ considerable confusion."

*EDIT* The original s300 is definitely gone, though. I will need to get that looked at by someone. */EDIT*

[TurboLS]

So, just as an update: the s300 w/ the serial number listed in the first post is definitely bad. Can I get an RMA#?

[Spunkster]

Send an email to support <at> hondata.com with the following and I will issue an RMA and give you further
instructions (include a link to this post):

Name:
Address:
Phone:
Email:
Serial#: