Nope, no fuel pressure switch on the line or the pump. It just runs full pressure for a couple of seconds then waits until you begin cranking.

Blown fuse?

 

just convert the whole car to RHD

 

This is the assumption I was under, as far as the operation goes. As for the fuse, I believe there is only a single 20A fuse that services the FP circuit. I checked it and it has continuity, does not appear blown. I removed it and the fuel pump does not work at all without it in place.

Doing a little more testing, both the "CIRCUIT" and "FUEL" relay coil terminals in the fuse box have about 11.6V all the time, however, neither actually activates the relays all the time. When I first turn the ignition on where the fuel pump should spin up the "CIRCUIT" relay coil voltage goes up to about 11.8V. When I do the FP check test I can hear the relay click. The "FUEL" relay always stays at about 11.6V. I am assuming this is some residual potential but no current behind it to activate the relay. So I jumpered the "FUEL" relay N/O contacts and the fuel pump spins up and sounds like it used to at startup. Seems like the ECU is not doing something here...

 

LOL I have been guilty of performing stupidly arduous tasks to achieve the insignificant

 

So just a sanity check here, can anyone confirm that the pump should be in high speed mode (bypassing the resistor) when it pressurizes the system just before startup? If not then I am just chasing my tail here, however, I am certain the pump used to be louder at startup.

I may need to use Brettus suggestion and hook up a light to see if it comes on at higher engine loads when the secondaries kick in...

 

can you check the resister, maybe it got to hot being by the turbo pips?

 

Your post implies high speed mode on start-up. You have actually confirmed this?

Everything I've ever seen indicates the engine starts up on low speed pump mode, but I've never physically checked it myself. The fueling requirement at start-up is very low. I don't see why high speed operation is required then.



Here's what the wiring diagram indicates:

High Speed mode only occurs if the FUEL relay is energized by the PCM. The CIRCUIT relay also has to be energized, but that's a given otherwise there is no power being supplied at all to the Fuel Pump wiring circuit.

The Low Speed mode is always energized when the CIRCUIT relay engages. The FUEL relay just provides a path of least resistance around the Low Speed Resistor for full voltage to the Fuel Pump.

The CHECK CONNECTOR energizes the CIRCUIT relay to power the Fuel Pump in the Low Speed mode only.


.

 

I considered the resistor. If startup mode is high speed pump mode then the resistor is bypassed. If low speed mode then perhaps the resistor is faulty and not delivering enough to the pump which is why it sounds much quieter at startup now. I just need to confirm startup mode operation.

 

Good info. I wish there was something definitive in there for us. It should be an easy enough check for someone with a known good system. With the FUEL relay in place turn the ignition to ON and listen for the pump. Then switch the ignition OFF, remove the FUEL relay and switch the ignition back to ON. Does the pump sound quieter? If so then the startup mode is high speed, bypassing the resistor. If sound is the same then startup mode is through the resistor. It would be difficult to tell with the OEM pump assembly, as it is pretty quiet already, but the Walbro is easy to hear the difference.

Just throwing it out there if anyone is up for a simple test

 

I did some tests yesterday but I cant seeem to trigger the high pressure circuit for some reason . Pretty sure (not 100%) that startup is low pressure only . Just by looking at my FP guage i can see this .

 

Ok, so that lines up with my current situation as far as not being able to trigger the high speed FUEL relay at startup. So my next quest is to figure out why the sound of the pump has changed at startup. Now, I know and respect all the arguments about subjectivity so I won't argue with anyone that says it's all in my head. Ya, and I also fully realize I just walked into that. That being said, in my head there is a marked difference in sound. This could coincide with Fazda's theory about the resistor going bad. If it somehow failed in a more resistive nature (not shorted or open, which is how I typically see resistors fail) then it would limit power to the pump at startup, reducing the associated sound level.

I now feel bad worrying about my hobby when a passenger jet was just reported shot out of the sky... So horrific and saddening that this can happen....

 

Would it make you feel better if I told you that my Walbro changed it's tone one day for no apparent reason ?

 

To some extent, yes, yes it would Did it change back? Did it result in any abnormal operation, lean fueling, motor failures?

 

It went from normal whirring noise to quite an unsettling noise that sounded like it was going to fall to bits then back to the normal whirring noise over the space of a few weeks.
Noticed no ill effects in fueling..............

 

Hrmm, that's the opposite of my experience. For me it went from regular loud "whirring" at startup to sounding almost like an OEM pump at startup and staying like that. Granted, for only a day now since swapping back. But the kicker is I can bypass the resistor by jumpering the FUEL relay contacts and it sounds normal at startup, hence me questioning startup behavior.

 

Reading back in the thread I want to make sure people understand what I feel "better" about is my fuel pump situation. The plane shot down is horrific. I am still flabbergasted.

 

gonna throw a wild goose out there

its been really really hot, what if the pump is quieter in the heat, and more noisy in the cold?

 

Good thought, but it was in place all last year (summer included) and never heard a change...

 

Yeah, just did a simple test myself. Start-up is low pressure only. I disconnected the resistor and the pump would not turn on at all to press up the system.

 

Thank you!!! That is tremendously helpful and I appreciate it!!!

EDIT: This is actually a much better test than what I proposed. No subjectivity in your test, purely objective. Disconnect the resistor and pump is either on or off at startup, nice work!

I will look for a resistor to swap out as next test...

 

it was definitive enough to finally generate some real answers/accurate information

 

Yes, yes it was!!! I hope this is helpful to the community vs just me By the way, I hope you didn't take the "definitive" comment personally. I was purely being pragmatic (at least in my own wee head)!

 

The lowest resistance scale on my multimeter is 20 ohms with 1 decimal point resolution. When I measure the resistor it shows .5 ohms. The value specified is .32 ohms. I can't find the tolerance anywhere, but if my meter is reading correctly then the value is considerably higher than it should be, 64% higher. I'll find another resistor and test.

Good call Fazda!

 

Also wanted to say thanks to everyone for the help!

 

Swapped out the resistor and pump sounds like it used to