Hondata

Since the ECU and S300 were both tested on an engine sim, I really think it's something with my car wiring. From my testing, I haven't found anything in the wiring that would cause the voltages to drop like that. The problems are only present when the P28 is attached, which makes me think it's ...

You should try the ECU on a known working vehicle to see if it works correctly there. If it does, then there appears to be a wiring issue in your vehicle.


I don't know anyone else with a 6th-gen Accord so I'm not sure how I would test it. I tested a lot of the wiring in my vehicle with this ...

This is the pinout diagram I'm using for all measurements (02D01720-1500 is the board in my ECU):

Car: 1999 Honda Accord EX (5-speed)
ECU: P28 — all capacitors replaced, J12 removed, and J1 jumped
S300v3 serial: 67277
Mods: Ghost key push button from Jordan Distributions, eBay cold air intake, full speaker system (removed for testing), 3-to-2-wire IACV conversion with Rosko conversion plate

1 ...

What is the battery voltage at the ECU measured with a multimeter when cranking?


Got my ECU and S300V3 back and nothing was wrong on the ECU end so it has to be my car's setup. I tested the power at the ECU connector and I'm getting 11.8V so it's definitely getting power. My S300V3 still won't ...

Had my ECU and S300V3 set up tested, and it came back completely normal. I think there is something wrong with my car's wiring that is causing the issue. Once I get my P28 back in the mail, I will troubleshoot further. Also, I don't think the ECU is losing power but the car is rejecting the ECU ...

I didn't even get to the cranking stage I couldn't get the s300 to power on correctly. I sent the ECU and S300 to the person I bought it from to test my combo. I'm gonna see what they say before I test any further.

Here are some pics on the ECU

Car: 1999 Honda Accord EX 5spd
ECU: P28 with all capacitors replaced
S300 serial number: 67277
Mods: Ghost key push button, air intake, full speaker system

Issue: installed s300v3 onto the p28 and hooked it to my car. At first the s300 was turning on fine and I uploaded my tune to the car. Went to ...