K swap wiring issue manifested over night [please help im desperate]

[bfce]

this issue probably isn't caused by hondatas products, I'm just hoping the many knowledgeable people of this community can help me

tl;dr my EG randomly developed a crank no start, fuel pump doesn't prime, MIL doesn't illuminate, hondata says ignition off

I have driven the car for about a year on this setup with no issues. A few days ago I did some spirited driving on back roads, parked the car for the night, and the next morning it cranks but doesn't start.

I've checked / replaced the main relay, and checked every fuse.

I've checked the main ECU ground on the valve cover

I've checked the ignition

The rest of the "run position" stuff works, like the gauge cluster showing oil pressure and battery light, turn signals working etc.

I'm thinking about making a jumper wire to provide 12V to pin E9 to see if the ECU will power on and run the car like that. But still unsure what might have caused this?? wtf happened? please help

The car has been using a genuine K-Tuned conversion harness which hasn't given me any issues previously

[Spunkster]

Try the ECU in a known working vehicle and see if it works as it should.

[bfce]

It will be a few days before I can do that, but I will try it and let you know. Are there any tests I can/should do to the ECU in the meantime before I can get access to another vehicle? I own a good multimeter and have some basic electrical knowledge.

[Coreynewman15]

Having the same exact issue with my RSX. I have tested the ECU/Kpro on a bench-tester, basically a breakout load box that simulates the outputs of the actual engine (injectors, coils, VTC etc...), uses the same pins as the ECU would for 12v power, ignition power, the grounds and was able to get the ECU to come on and read "ignition on." My setup has also been running without issue for over a year, took the car for a spirited drive as well, and had the thing shut down on its own as though I turned the key from position 2 to off. Any pointers or help would be greatly appreciated in specifics as I have already gone through checking harness, connectors, the three Engine/Transmission to chassis grounds, as well as the following circuits: A2, A3, A4, A5, A10, A11, A23, A24, E1, E4, E7, E9, C104 Junction connector. Vechicle cranks but will not start, Immobilizer has and had been disabled within the calibration prior to issue.

[Spunkster]

Have you tried it in a known working vehicle?

[Coreynewman15]

Yes, and it operated as intended - indicating that the ECU is working as it should. This tells me that the vehicle wiring has a fault. That being said, it is possible that the ignition switch power feeds/distributions having a fault could cause this issue if I'm not mistaken. Just scratching my head trying to figure how I have battery voltage present at the ECU pins indicated in my prior post.

[Coreynewman15]

Any circuits in particular I should give more attention to? As said, my grounds are all tested good and ran as per Hondata.

[Spunkster]

You will have to go over the wiring methodically to determine where the fault is. Since it works on another vehicle, you know that the ECU is not the problem.

[Coreynewman15]

I know the ECU is good, my question is more so - what input does the ECU need to receive in order to read "ignition on," and therefor output the low-side driver for fuel pump relay control (ECU connector E, pin 1 - IMO FPR) and function. Is there a specific Ignition Input(s) that should be traced down in order to rectify this condition? I see that there's A2 and A3 - "Ignition Power +12V Switched Input Dedicated," but I do in fact have good battery voltage at these pins at the ECU connector when the key is cycled to ON/Run.

[Spunkster]

I recommend that you contact K-Tuned for help with their harness.

[Coreynewman15]

I'm not using a K-tuned harness, factory rsx harness. Just would like to be pointed in the right direction of possible causes or circuits of higher probability.

[Coreynewman15]

Just figured out the issue. Vehicle speed sensor (VSS) on the transmission was broken upon removal - causing a short in the sensor reference circuit to ground. I assume this causes the lack of communication to the ECU, and therefor doesn't turn on/prime fuel pump etc.