So my 92 integra was pretty much torn completly down and im trying to basically put it back together, i have both fuse boxes inside the cabin all hooked up and so far i am getting 13volts to my horn, corners, lights, ect.

Thats telling me the underdash harness is ok and getting power

As for my cabin harness i got it all hooked up and can control my power windows, sunroof, mirrors, but for some reason i cant get my fuel pump to prime. I get zero volts to the plug directly?

i have tried a few different relays with no luck, the main realy plug gets 13volts in 3 of the ports. I have checked all the fuses but might have to check again.

Im just wondering if i need to plug my ecu in to get the pump to prime??
i would just toss that sucker on there and check but its a brand new s300 and dont wanna fry it over something stupid.

 

Not trying to start the car just wanna make sure i can get fuel to spit out the hard line so i know the walbro pump works.

Thanks.

 

Going home to work on this problem bump, anyone?

 

nobody???

 

yes, ecu controls the relay.

 

Ahhhh ok ok, maybe ill stop being a panzy and plug it in just to make sure the fuel pump was a success. Thank you

 

Ignition switch controls the relay, not the ECU.

 

Now im confused... the ignition switch sends 13 volts to the main relay and it clicks when i turn the key but doesnt give the "click then 2sec delay click" when i turn it to the on position.

 

Mixed review bump??

 

On my crx unplugging the ECU disables the 2 sec prime of the pump.

 

the ecu grounds the relay. drr

 

ECU pins A25/B1 power the fuel relay part of the main relay and pins A7/A8 ground it. So without the ECU not sure how the fuel pump would prime.

 

It doesnt prime when the ECU is missing. /story

 

Ditto the above, no ECU/ECM = no fuel pump power.

The ign. switch controls the fuel injector relay, [power to the relays coil, other side of coil is grounded] it is also power for the fuel pump, [through the fuel pump relay] the fuel pump relay is controled by the fuel injector relay, [supplies power to the fuel pump relays coil] the ECU/ECM supplies the ground for the coil. 94

 

Thank you to everybody who cleared that up, but still no luck. More activity/clicking from the relay but not quite.





"Putting on my flame suit"



I guess my next question is does the engine harness ALSO need to be plugged in for the pump to prime?


Judging by what FCM said here that would be a yes??






Thanks again.

 

**** all that. Bypass it n see if it starts!!! I bet its open wire. !!!

 

Yes. The engine harness loom contains the ground for the ECU. That is usually the very first wiring troubleshooting suggested to people with a no start issue, having a no fuel and or no spark.

 

Both the ignition switch and ECU control the main relay both need to to energize to get output to the fuel pump. There are actually 2 relays built into the main relay. You could ground it out once you found which pin comes from the ecu. With ignition on this should energize the fuel pump once the ignition is on.

 

As mentioned, engine harness must be installed/connected, pay very close attention the the grounds at the thermostat housing.

To test the PGM-FI Main Relay and it's wiring find the green/black fuel pump control leads at the ECU/ECM plug, [there ar two (2) of them] they are the only green/black leads at the ECU/ECM, turn the ign. switch on to the run position and use a jumper to supply a ground to either one of the green/black leads, if fuel pump runs, the PGM-FI Main Relay is good, along with wiring to it.

To confirm fuel injector relays output, [fuel pump coil is internal] with the ign. switch on test for power at IGP1 and IGP2 at the ECU/ECM, it will be the only two (2) yellow/black leads at the ECU/ECM plug(s) also test for power at the fuel injector power leads, also yellow/blacks, the injector relay also powers the IACV and the Heated O2 Sensor, all are yellow black leads.

If on the other hand the fuel pump does not run when grounding the green/black, you will need to test wiring at the PGM-FI Main Relay

Black - ground, fuel injector relays coil ground, should have full continuity to chassis ground.

Black/yellow, switched power, [hot in run and start] fuse 24-15A, in under dash fuse box.

Yellow/white, constant power, [hot at all times] fuse 38-10A, engine bay fuse box.

Blue/white, switched power, [hot when cranking to start only] fuse 18-7.5A, under dash fuse box.

Green/black is fuel pump control lead from ECU/ECM, it is a ground supply from the ECU/ECM to the fuel pump relays coil, check for continuity of the led between PGM-FI-Main Relay plug and ECU/ECM plug.

The two yellow/black leads are the PGM-FI Main Relays outputs, one is from the fuel injector relay, the other is from the fuel pump relay. 94