Interesting Fuel Pump Part

[Hijacker]

So, we all know that the stock 240 pump sucks monkey balls when it comes to flow rate for an SR. In the past, I used to assume that the 240 and the Silvia/180 used the same fuel pump, but after seeing this in the 180SX circuit diagram, I take back what I said.



Apparently, the JDM models got a fuel pump that was more akin to the one in the Z. I'm not certain on flow rates, but this part of the circuit diagram shows that the ECU controls a regulator circuit for the fuel pump. Probably to slow it down for idle speeds and the increase it for running at load.

Either or, nice to know. It's a shame we didn't get that over here, though.

[karmakaze]

what would the benefit of that be over wiring your fuel pump directly to the battery (via a relay of course)?

[Hijacker]

That little part is really there to vary pumping speeds of the pump by modulating voltage. It would just keep the pump from going full tilt at idle as best as I know

[T-rev]

You could almost make up some sort of trick circuit to mimic that. I dont know how a shift like works, but if you could get a lead off the tach, you could make a similar setup to use 2 relays and have a lo and hi setting for your pump.

At idle (or <1200 rpm) you run the power through a relay and a resistor to the pump for the lo setting. Over 1200, and you switch to a second relay running straight 12V to the pump, hi setting.

[duffman1278]

So I'm assuming your working on translating the 180SX FSM again? Good info though

[Hijacker]

I've just been meaning to post that for a while. I translated the circuit diagram at the end of the engine section a long time ago. I'm still trying to get motivated to finish up the technical parts, and I need to figure out a way to import the PDF into my corel photo program (supposedly v10 can do it, but I'm running v8). It took me forever and a day to screen cap/paste the vac diagram and I'm not going to do that for every page. If I could find a new power brick for my laptop, I could easily do it all in photoshop 6

[seanman]

on the topic of fuel pumps, i hear alot about the walbro 255 being louder than the stock one. I was wondering how much louder it usually is. I can hear it quietly whining in my hatch. Just curious

[idahotuner]

my walbro is supper loud. when it presurizes.

[Hijacker]

I only hear mine when it first primes. After that, I can't hear it.

All the Walbros I've used in multiple S chassis cars are like that.