In a local dealer here in Malaysia brought in straight from Japan. They have 3 variants a 210 l/hr, 265 l/hr and a 285 l/hr unit. Looks a lot like denso.

 

Kansai Service also has a pump that looks like the Walbro. Only difference is it's black.
check www.kansaiss.co.jp

 

sorry a bit off topic and newbie question

What are fuel pumps for and when is it necessary to install them? If you get bigger injectors I assume a fuel pump is needed?

 

I am getting my Walbro soon. Locally, we can only find the Power ones so I shd be able to do a visual check.

 

Yeah but it's USD289. Oh yeah, It's JDM...

 

Also Walbros make more noise then other pumps because they have metal gearing instead of plastic

 

If you do want to use a boost controller, you might need to check that yr fueling is up to scratch. Too much boost, and too little fuel makes for a bad detonating combination.

Beefing up the fueling system helps ensure you get sufficient fuel to the engine to prevent that.

Start off with a fuel pressure sensor, preferably one that can do fuel pressure differential (ie FP - boost pressure). Defi BF system can do this, as long as you have both the fuel pressure sensor and the boost sensor hooked up to the system. Just press the Up and Down buttons at the same time and the FP Diff red light on the left will be lit.

This will now display FP differential rather than instantaneous FP and the differential is far more meaningful.

Under WOT, you should ideally maintain FP diff >= 3.0

If it dips below 3.0 for too long a period, chances are you are running lean.

The solution is to get a fuel pump to deliver more fuel per second.

You also need to get a fuel pressure regulator to adjust the flow to maintain the >= 3.0 differential. I set mine to 3.6 and with the stock fuel pump, it still dips below 3.0 occasionally. Already ordered my fuel pump.

Getting bigger injectors will also be a possible solution, but this needs to be upgraded along with the pump and regulator. More importantly, you need a new ECU to control the bigger injectors.

(YMMV.. this has been gleaned from discussions with far more informed friends and mechanics)

 

propellerhead: have you observed the Walbro over-running the OEM FPR with the fuel pump running through the resistor?

 

That's interesting. I've never heard that or read that before. It is my understanding that in most situations, fuel pressure will rise in a 1:1 proportion with boost pressure at a linear rate.

For example:
Adj. Fuel Pressure = base rail pressure + boost
Base rail pressure: 43.5psi
Boost pressure: 20psi
Adjusted fuel pressure: 63.5psi (under 20psi of boost)

This arrangement means that there is effectively always 43.5psi of fuel pressure at the injector tip. Fuel delivery will respond linearly as injector pulse width increases and boost increase.

If you're seeing 3psi higher fuel pressure than boost, then yes, you would probably run lean if that value dropped. This seems unique to your situation. I'm not certain that this is the norm. I may be wrong but I'm guessing gauge inaccuracies. By no means is it a big deal. Once you know what you need to be looking for you can spot problems.

The question this raises for me is whether or not the response curve of the OEM FPR remains linear when using an aftermarket pump. In my experience the 255lph Walbro overruns the OEM FPR at idle/vacuum resulting in a higher than normal base rail pressure. I wonder if the response is linear under across other differential pressures.

 

Yep. My limited experience has been that the Walbro will raise the base fuel pressure from the spec'd 43.5psi to ~52psi (key on, engine not running). This was tested back at the pump so the actual pressure at the rail might be slightly lower. Or it might even be slightly higher with the motor running since the supply voltage would be higher. Your mileage may vary.

 

It's nice to hear of another data point. My car had issues too.

 

Have you monitored fuel pressure under load though?

 

The Power 255 unit is (or was) a Denso Supra pump...their 210 unit is (or was) a Walbro last I checked)

 

Nope. Not in this case anyway. We were following the basic factory diagnostic procedure.

In the future I'll be adding a fuel pressure sender and at the bare minimum I'll use it to log data. If I can get over my perceived "rice-ness" of an A-pillar gauge mount, I might add a fuel pressure gauge.

 

So does the walbro 255 out flow the stock FPR? I was told by a few it does not.... I had 1 on my DSM and that I was told will out flow the stock FPR and I never had any issues with it though....