Help chasing electrical gremlins....

[frozenrice]

Off the bat ,when it comes to automotive electrical in general, I'm a bit of a lost cause. I'm having a starting issue with my early 90's Integra. When I say starting issue, I'm not getting the fuel pump prime step when I turn the key. I've done my reading online and have checked all the obvious things that most everyone suggests (main fuel relay, ignition switch, battery, grounds, ecu, etc). I've metered all the connectors to and from the relay and ignition switches and fuse boxes for continuity and voltage and everything seems to check out. My only guess at this point is there is either a ground/short somewhere that is causing the relay to not prime the fuel pump. I'm just not sure at this point how to find the problem and I'm second guessing myself if I've done all the checks properly.
Anybody out there that can offer suggestions and/or help? I'm completely stumped and frustrated at this point.
I should also add that the car has been modified so some of the wiring isn't necessarily stock.

[revelations]

Do you have an aftermarket alarm with fuel cut?
Have you tried running 12v directly to the FP ? Isolate and work backwards from the failed part.

[rage2]

Check the main relay. Known Honda issue of that era. My old civic had this problem, car won't start intermittently especially when it's hot. Car just cranks endlessly. When the main relay goes, fuel pump and ECU doesn't get power.

[frozenrice]

The main relay was he first thing i suspected. i even swapped it out with a few different ones including a new one.
I'll check the fuel pump, it's aftermarket so somewhat newish so we'll see.

[ExtraSlow]

Chasing a possible short somewhere can be maddening. At some point it's easier to just run new wires.

[Gestalt]

You can start at the relay. Does it click when you key on? Yes no.
If no, does it have power (use a test lite).
If yes, then is it getting a signal when you key one? (Use a test lite with alligator extension clips so its easier to see).

Now you know if the problem is before or after relay and if its power side or signal side.

Main relay will also supply power to fuel injectors so check for power there with key on.

[frozenrice]

There is power to the relay and as far as I can tell there is a signal when key on but no click from the relay. I've checked the relay itself and a couple of spares several times and they all seem good. This is baffling me and why i'm saying i'm second guessing myself as i'm obviously doing something wrong.

[Gestalt]

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There is power to the relay and as far as I can tell there is a signal when key on but no click from the relay. I've checked the relay itself and a couple of spares several times and they all seem good. This is baffling me and why i'm saying i'm second guessing myself as i'm obviously doing something wrong.

So the ground must be bad.

If you have battery power, and when you key on you also have ignition power, and tje relay doesnt click and send powet to ecu, then either its the ground or the relay.

[frozenrice]

Is it possible that there isn't enough grounds? I relocated the battery to the trunk and when i did that i didn't make up for the one that goes from the battery to the engine block/transmission and relied on the valve cover to body ground. The battery negative is grounded to the rear shock tower in the trunk. It never gave me any problems before this problem started.

[Star1995]

Have you explored other options such as sensors? I had a Ford Winstar that would turn over but not fire, after draining the battery a couple of times thinking it was something to do with the fuel pump or something related I found it was the mass airflow sensor in the air intake. disconnected that and it started, replaced it the next day and all was well after that.

[revelations]

Did you check the FP already by running 12v direct to it? You should try to isolate the failed part.

[legendboy]

Pull the loom off where ever you suspect there could be a long term rubbing issue, if any.

Disconnect oem wiring and wire your own system? haha

[Gestalt]

I have a wireless signal tracer if it come to that. But it should be straight forward.