Hondata

Here's my problem, from about 9am to about 3pm my car doesn't prime the fuel pump to start, I've tested the pump and it works fine, I've been able to apply power to the pump manually and it pressurizes but the car still wont start.

I've got a brand new yellow top optima that's fully charged, the starter turns without any problem but it still dosn't start up. I've hooked up my laptop to the S300 when it is in this condition and none of the sensors show up, it just gives me 0s for everything, normally it would at least give me the ECT and the MAP, but it's completly blank.

I'd like to know what wires going into the ECU might cause it not to turn on completly so I can test them for proper power and ground.

Sounds like the main relay.

Try the ecu in a known working car.

the PGM-FI main relay has been replaced about 3 months ago hoping to solve this issue.

I don't have access to a known good honda.

I just want to know the wires that deliver power for hondata s300 to recieve sensor information, etc and proper grounds as well. That way I can check those lines and trace what could be causing it on either side of the ECU.

I know the main relay is working properly, I can apply power to the relay and it will click, somthing dosn't seem to be telling it to actuate is more of what it seems like, and it has to have somthing to do with power to the ECU, so if I can eliminate some wires it'll make it a whole lot easier to troubleshoot.

What vehicle is this in and what ecu are you useing?

2000 accord SE with OBDII to OBDI conversion harness.
USDM P28 ECU.

Are you using an OBD2A or OBD2B harness. WHen you plu the harness into the car, is there a gap between the plugs, or are they all 3 together?

the OBD2 side of the harness is all one block, plugs A, B, C, D. the OBD1 side of the harness is each plug to itself plugs A, B, D.

When you plug in the stock ecu, are all 3 plugs together or is there a space?

this was an auto to manual swap, there was 4 plugs.

according to what I just researched.

OBD2A to OBD1 Harness
Accord (1994-1997) 1996-1997
Civic (1996-2000) 1996-1998
Del Sol (1993-1997) 1996-1997
Prelude (1992-1996) 1996
Prelude (1997-2001)
Integra (1994-2001) 1996-1999

OBD2B to OBD1 Harness
Accord (1998-2002)
Civic (1996-2000) 1999-2000
Integra (1994-2001) 2000-2001

Post a picture of your adapter harness

here's some pics

the wire that's spliced into is SCS.

one more thing, I decided to pull the ECU out to look at it this morning, and I get a constant red light from the S300 when I turn the key to ignition II.