Hello,

I have made it to the end stages of my swap but I'm having a no start issue and I'm out of ideas.

My injectors have 0v. I tested the PGM/FI and found that it is in working order. I can remove the PGM/FI and jump the plug and get voltage at the injector. What are all the other leads into the PGM/FI and what should I be looking at now to get the voltage back at my injectors?

Please keep in mind that I have reached this point after painstakingly chasing down all the other usual suspects.
40psi in the rail.
Good strong blue arc on all plugs.
compression is good:
1 - 162
2 - 160
3 - 161
4 - 160.

 

Double check the ground connection at the thermostat housing.

Are you using a new-to-you ECU with this swap? Open the ECU up (both front and back) and see if any of the electrolytic capacitors are leaking and/or if the board is damaged.

When you say the PGM/FI, are you talking about the main relay?

Do you have a copy of the factory service manual?

 

__________________________________________________ ___________

Ground at thermostat housing is solid... ECU is grounded

ECU is new to me P75, I cracked it open and verified no leaky caps. Thought I found what I thought was a crack in board but continuity test indicates not a crack

PGM/FI is my main relay. Brand new, just purchased yesterday. It clicks 3 times... once when key is turned on, once when EGR light comes on (and fuel pump primes), and once again when light (and pump) turn off.

I have a Hanes Repair Manual

I have spent 8 mo tearing down and building back with B18B1. I've converted my original harness first from DPFI to MPFI and then OBD0 to OBD1 using a guide obtained from the guys at swap shop racing (attached).
I was hoping to keep the harness simple by using current wires but I have seen and heard of builders running all wire for injectors directly from the ECU. I left A1 and A5 stock and ran new wire and sub harnes for A3 (injector 2) and A7 (injector 4). All four yellow with black strip OBD1 injector 12v wires were connected to the 2 yellow with black stripe injector wires from the OBD0 harness. Would a possible fix be to run the power for injectors direct from ECU A15 to the four yellow with black strip OBD 1 Injector 12v wires?

 

For my MPFI swap, all injector 12V wires go to the YEL/BLK wire on the driver's side 14-pin connector (C122) that originally went to the AUX (top / brown) injector on the DPFI setup. I too only ran a A3 and A7 through a sub-harness, and re-used the existing wiring for A1 and A5. You can certainly try using another switched 12V source to see if that works. Even if you temporarily check it out, it will tell you if you have an issue with your current injector 12V source.

 

I'm at a loss... I verified the line from ECU to main relay and it's at 12v. I can remove the main relay plug and insert 3 jumper wires essentially bypassing the relay. All dash lights come on constant. I have 12v at my injectors. If I put the main relay back in, I loose voltage at the injectors. I cant find a schematic for the main relay so I don't know if there is something else that should be triggering the main relay to rout power to the injectors.

 

Literally the first thing that comes up when you google image search "Honda main realy" is a schematic from the factory service manual...

 

I found that first image too but there is no reference to the injectors.
1 Battery
3 ECU (13, 15)
5 To Ignition
7 To Fuel Pump

2 Ground
4 Start Switch
8 ECU (12, 14)

I didn't find a fix so I just bi-passed the main relay and ran a switched 12v from A15 to my injectors. Problem solved... Thanks for the help!