Walboro 255lph fuel pump on a NA KA

[hoosier240sx]

So a while back my fuel pump went out and every told me to get the 255lph walboro unit. I installed it and it works fine on my freshly rebuilt KA motor. The motor is NA, but is built for turbo. I think my pump is causing me some problems....When my car idles it sputters in and out and idles really really low (SOHC to DOHC swap problem I think) and also when it idles unburnt fuel/carbon is coming out the back of my exhaust. Also when I get on it, a lot of greyish smoke will come out the back of the exhaust at first then it will disappear. Anyone know if my pump is pushing too much fuel into my motor or is my timing off?

[benz88]

sounds like timing. I have no problems with my Walbro + Z32 filter.

[pella]

I added a z32 fuel filter, and a walboro 255 about a month ago to my NA KA, no problems other than the pump itself is pretty loud.

[Lobo240sx]

Timing. Walbro pumps flow according to factory pressure. The extra fuel is dumped back into your tank.

^ yes those pumps are extremely loud been through 4 of them myself.

[asoomal]

If your FPR is weak (the spring starts to get weak), the higher flowing fuel pump WILL cause it to run rich and like crap.

[DanThaMan]

I would also check for vacuum leaks, especially on the line going to your FPR.

[AZ89two4Tsx]

Be advised, Walbros are notorious for failing unless you run them over a 1/4 of a tank of gas. They cool themselves by being submerged in fuel.

Might be why you've gone through 4 of them Lobo.....

[Lobo240sx]

Be advised, Walbros are notorious for failing unless you run them over a 1/4 of a tank of gas. They cool themselves by being submerged in fuel.

Might be why you've gone through 4 of them Lobo.....

Between 2002-2004 when I got my 1st SR20, they were having a lot of problems with the old Walbro 255lph design. I noticed when I got my up to date one this year, the sock and hole are wider at the bottom allowing the pump to cool better. I hardly ever ran the tank down to 1/4 back then. Yes you are right that was one of the issues people ran into.
Plus I had to modify the metal canister by sanding the lip off where the old rubber piece sat to make the new one fit.

[benz88]

My walbro's lasted me over a year now, where as i went through 2 OEM Bosch ones in under a year. Never again will i buy anything bosch.

[pella]

If your FPR is weak (the spring starts to get weak), the higher flowing fuel pump WILL cause it to run rich and like crap.

Is there a way to check that the FPR is working the way its supposed to?

[asoomal]

Check fuel pressure at idle, should be around IIRC 38-39 PSI.

Remove vacuum line from FPR, or pinch it, pressure should go up to 43ish.