No power at fuel pump

Kyxxer

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first time poster long time reader!

Okay I'm going to explain this the best i can .......

around 1 month ago, i started my car then it began to spit and sputter and die... threw a low fuel pressure code, the fuel pump wouldn't turn on to prime the system but 30 mins later the pump turned on primed then it started right up fine without issue.

Then last week the same thing happened again i let it sit for an hour then it started without issue.

This past weekend it began doing it every time i went to start the car (low fuel pressure pump not turning on to prime the system) and it became harder and harder to get it started until it wouldn't start anymore. The fuel pump would no longer turn on. Note when the car did start it worked flawlessly as i monitored everything with my hondata to see how the fuel system was working while driving. It appears to be the initial fuel pump prime is the issue as once the car starts it works fine.

So a 301km tow home (not covered by honda)and i tear into the car to try and figure this out. So what i have come up with is the following:

Relay is getting power and functioning (even replaced it to make sure)
Fuel pump fuse is okay (even replaced it to make sure)
Fuel pump does NOT have power at the pump connection on top of the tank
The fuel pump fuse does NOT have power
Hondata log shows with the ignition on the fuel pump duty is at 100%

So my question is there a module, sensor, regulator or anything in between the fuel pump relay (in the engine bay fuse box) and the fuel pump fuse (in the cabin)
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kefi

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Ooh, a proper mystery.

This probably won't be much help, but there's usually an inertia switch that can de-activate the LPFP in the case of a crash. This way fuel isn't spraying everywhere after an accident. Common reason for why totalled cars don't start at auction lots. Whether it's on the FK8 or exactly where it would be I do not know for certain.

There's a recall for low pressure fuel pumps, many have been failing lately, but I don't think it has to do with the electricity.
 

DRUSA

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Looking at a wiring diagram for your car (Leaf FK8), unless you have a blown 30A A2-2 fuse (the under hood fuse box, the 5 wide multifuse that is bolted in to the box using a 8mm bolt) then you have a BCM issue. If the underhood fuse block A2 is all good and the 20A fuel pump fuse is good, then you either have a relay issue which is internal in the underdash fuse box OR the BCM is failing, not providing the relay control side with ground or power.

Wouldn't be the first BCM failure I've seen lately, you need to provide more voltage readings in order to pinpoint the failure. BCM's have the immobilizer integrated into them, so this is a replacement that needs to be performed at a dealer as the car will not start without programming. Not a DIY repair.

Verify the pump has no voltage by back-probing the connector while it is connected, we never test disconnected circuits like that. If you end up having voltage during the failure event, its a pump failure. Pump failures are very common right now, they have recalls about them seizing up.
 

oceancamp

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first time poster long time reader!

Okay I'm going to explain this the best i can .......

around 1 month ago, i started my car then it began to spit and sputter and die... threw a low fuel pressure code, the fuel pump wouldn't turn on to prime the system but 30 mins later the pump turned on primed then it started right up fine without issue.

Then last week the same thing happened again i let it sit for an hour then it started without issue.

This past weekend it began doing it every time i went to start the car (low fuel pressure pump not turning on to prime the system) and it became harder and harder to get it started until it wouldn't start anymore. The fuel pump would no longer turn on. Note when the car did start it worked flawlessly as i monitored everything with my hondata to see how the fuel system was working while driving. It appears to be the initial fuel pump prime is the issue as once the car starts it works fine.

So a 301km tow home (not covered by honda)and i tear into the car to try and figure this out. So what i have come up with is the following:

Relay is getting power and functioning (even replaced it to make sure)
Fuel pump fuse is okay (even replaced it to make sure)
Fuel pump does NOT have power at the pump connection on top of the tank
The fuel pump fuse does NOT have power
Hondata log shows with the ignition on the fuel pump duty is at 100%

So my question is there a module, sensor, regulator or anything in between the fuel pump relay (in the engine bay fuse box) and the fuel pump fuse (in the cabin)
I am experiencing the same problem you described.
We also changed the fuel pump motor with the new one supplied by Honda, thinking that might be the issue (as per the recent fuel pump recall), but after a few miles the issue came back, car would not start (or start, splutter and die).
Please share your experience if you managed to pinpoint the issue.
Thanks.
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