Car suddenly will not start and ecu LED not lighting up

[AAGibson]

Hello, I have a k-swapped integra with 05-06 RSX Ktuner ecu. The car has been running fine with an intermittent speedometer issue, which I posted on another topic. Today, we drove to the store and parked the car. After an hour or so, we tried to start the car and it would not start. The engine cranks, but it will not turn over to start. I started troubleshooting by looking at basic things such as fuses and notice that the fuel pump was not priming. I then checked the ecu (hidden behind the kickpanel) and there were no LED lights on with the key turned to ignition. I unplugged and plugged it back in, but no luck. I had to tow the car home tonight.

I have not tried to connect it to the computer yet, but I doubt that will make any difference if it is not powering on with the ignition, connecting the computer makes no sense to me... I will try that tomorrow... just to eliminate it.

Any ideas what could have suddenly gone wrong? Do I have a bad ecu all of a sudden? What do I need to check to eliminate wiring? I checked the fuses and they are all good. I changed out the relay in the swap conversion harness just in case, but no change. I would appreciate any ideas or suggestions to help troubleshoot this issue.

Thank you.

[KTuner]

If you connect USB and the unit powers on then the unit is functional and the ECU is not providing power with key on. That's indicative of an issue with the ECU.

[AAGibson]

Thank you for the response. I will test that later today. If I connect the USB to the ECU and it powers on, would such an issue require that the ECU be returned to the seller? I am assuming that this indicates that it is not an issue with the wiring on the car, correct?

[KTuner]

If your ECU has failed that could be due to wiring or something else.

[AAGibson]

It must be due to "something else" because it was working fine before. We drove to the store, parked in the parking lot, when we came back out to leave an hour later, it would not start. I have sent the ecu back to HA Motorsports. They have done initial testing and updated me with this:

"We received your ECU today, thank you. We tested your ECU as-is and it powered on and runs. We then connected the USB to test connection with KTuner and it connected and datalogs. We will be doing further testing later this evening, but just wanted to let you know before you go purchase another ECU that so far it looks like the ECU is good. Will get back to you on Monday, thanks.

Before sending the ecu back, I did the following tests and they all passed:

With the ECU NOT plugged into the vehicle harness:
1. Checked for continuity to ground at all of the following pins at the ECU connectors: A4, A5, A8, A9
2. With the key in the 'on' position, check for +12v at pin E9
And
3. With the ECU plugged into the vehicle's harness, and both sides of the C101 plug connected together, checked for +12v on pin 14 With ignition on.

Now I'm really stumped how HA Motorsports could get the ecu to function and I can't even get it to power up.

[KTuner]

That would stump me, too. If it powers up on a test bench I'd assume it'd do the same in the vehicle.

[AAGibson]

So for an update:

I received the ecu from HA MOTORSPORTS today. I plugged it in and the ecu still does not power on. So I started testing the Main relay.
1. Pin 1: tested for battery voltage without ignition - test passed.
2. Pin 2: tested for continuity to chassis-ground - test failed.

I have spent the better part of the afternoon trying to figure out this issue. I traced the wire into the chassis harness (that part of the harness that is at the shock mount that is pushed back into the dash to connect to the conversion harness), then across the conversion harness to the E plug. I think it is at E7. So there is continuity from the main relay all across to E7.

I tested E7 under the Honda manual conditions:
1. Ignition on II - 0 voltage
2. Ignition off - battery voltage.
Test failed. Of course it would fail because the ecu does not power on. I read somewhere that the ecu supplies ground, it that correct?

This is as far as I've gotten. Any help you can provide as to why my main relay ground has failed, I would appreciate it.

[AAGibson]

So, since the last update, I have sent the ecu back to HA Motorsports and they have done their own tests. The ecu still did not power on after returning. Evidence seemed to point to the ECU, so I purchased a different ecu and send it back to HA Motorsports to install the same ktuner board on it. I received it yesterday and the ecu still will not power on.

I tested the unit with power and ground on A2 and A4 and it lit up.
I installed a brand new main relay from Honda. No change.
I changed all the fuses in the fuse box. No change.
I tested all the wires for ground back to the harness at the injectors, and there was continuity. So I don't think it is the engine harness.
I installed a second conversion harness, so I swapped it.

So the ktuner board powers on with direct power and ground, when it is not connected to the car. But when it receives power and ground through the harness, it does not power on. My question is whether the Ktuner board could be malfunctioning and fail to power on when connected to the car? Have the ktuner boards been known to fail?

[KTuner]

You're assessing this incorrectly. Power and ground to the ECU powers the ECU, not the unit. The ECU then powers the unit. The unit does not power the ECU or affect ECU power. A failed unit would not turn on. You already assessed that the unit does power on when the ECU has power, which also means it'll power on with USB power as well.

[Linszter]

Have you checked A3 and E9 for power too?