Hondata

Even though you guys (Hondata) recommended not doing it, I saw that people on K20a.org had relocated their batteries to the trunk. I ran 1 gauge wire from the alternator to the battery and 4 gauge from the starter to the battery.

When I turn the key to the 'on' position there is a buzzing coming from the relay under the dash. I checked all the grounds on my engine with no change. Thinking it was the battery, I hooked the charger I have up and put it to the jump start mode. Flipped the key to on, no buzzing, fuel pump comes on.

So I drove over to Sears and bought a new battery. Came back, installed it, flipped the key, buzzing again.

Should I abandon the idea of relocating the battery to the trunk, or do you think there is something else going on?

Just checked the voltage at the fuse box with a voltmeter. Without the battery charger hooked up it was ~12.5V with the key in the on position.

When the charger was hooked up it was ~17V with the key in the on position.

I'm going to rewire the car with the battery back up in the front tomorrow and see what happens.

Also found out that I need a new injector o-ring...

It probably is not from relocating the battery.

Has the car run before? If so, then it is someting you've recently changed. If not, then it is the swap harness or a ground point.

Yeah car ran fine before with a turbo D16 setup (on S300).

The swap harness is from Rywire.

I have all the grounds listed on the Hondata info page. The ground for the battery is also good.

When I was messing around with it over the weekend it kicked the fuel pump on once which threw me off.

I was thinking of redoing the battery wiring to see if that changed anything, but it looks like I might be spending more time with the factory service manual tracing wires down.

Checked out the swap wiring harness.

Traced for continuity from the main relay plug to the under dash connector (this is on a 1998 Civic DX). Everything looked ok except for Pin 3 on the main relay.
It goes to the DLC connector once its on the swap harness.

Did some reading on K20a.org and found that pin 3 for the main relay should be the ignition signal from the ECU (link here).

Pin 7 on the ECU E plug [PGM-FI Main Relay] goes to the oxygen sensor.

I'm going to spend some more time in the morning tomorrow sorting through the swap harness to figure out exactly what is going on.

The buzzing could be the ECU output shutting down from over current. Are you using the main relay from the vehicle, or another relay as the main relay? The wiring for the vehicle main relay is the opposite of the K engine, so you cannot use it. Many swaps wire the ECU main relay output to +12V and burn out the ECU - check your wiring against the diagram before you power it up again.

The buzzing is coming from the vehicle main relay.

If I wanted to use the wiring diagram from the tech section on the main Hondata site, would I use two different relays rather than the vehicle main relay?

Right now the ECU main relay output is going to the oxygen sensor, though I am not sure which wire from the sensor it goes to.

Talked to Rywire, he said it sounded like it was the wrong harness. He sent me a new one and I sent the old one back. Flipped the key to on, fuel pump comes right on.

Glad they took care of it. All is well now. It didn't sound like a problem from battery relocation.