Tuesday, July 5, 2022

What's This Weird Sound??

So check this out:

So what does this sound like? Initially I thought that this was my fuel pump going bad.  And it's hard to say where the sound is coming from in this video, although to me it seemed to be coming from behind the rear seats.  Thus, fuel pump? After all the pump was replaced back in 2007 with the Mine's engine, surely after 15 years it could be failing?

Well, turns out that I was wrong. Because the sound is coming from the Tomei fuel pump regulator.

This thing. I don't have video but once I had someone turn on the ignition with the hood open, it was clear where the noise was coming from.

A bit of research reveals that with this fuel regulator, it tends to lose the pressure in the fuel system that is always there - about 2kg worth - over time. So after a couple of weeks of not using the car, the pump effectively has to prime the fuel system and thus you get that noise.

So the way to fix this problem is to start up the car every week! Give me an excuse to drive the car around and this should no longer be an issue! But has anyone else encountered this problem? Please comment and let me know, including if you have a solution to this! Thanks!!


Anonymous said...

I have no personal experience with the Tomei FPR, it's possible that because it is not designed for emissions that it has a significant bleed-down if the pump isn't running. Other adjustable FPRs I've used tend to lose fuel pressure pretty quickly after the pump turns off, I had to set the ECU to run the fuel pump prime as soon as the ignition is on to have less issues with fuel pressure at start. You can try testing the FPR for leaks and repairing it if any obvious ones are found. If you've tried everything maybe the Nismo adjustable regulator will be less likely to bleed pressure after shutdown? To me it looks identical to the OEM regulator, only difference being that the OEM regulator has a fixed spring preload while the Nismo part you can turn the screw to adjust the preload. The downside of that setup is it requires something that resembles the factory fuel rail and it has very little capacity to bypass so if your pump flow rate is not carefully controlled to avoid overwhelming the FPR you will have excessive fuel pressure.

Aki said...

Awesome! Thank you very much for the through analysis and suggestions! Will see what I can do...