walbro 255 volume test

[omgwtf]

has anyone ever seen how far the spray distance is for a walbro 255. im having a lean accel condition and am checking my fuel pump. its getting 36psi at idle with vacuum connected where it should be for ca18det. when i disconnected the line to see how far it would spray it made it maybe 10 inches. it seems like this is a weak fuel pump.. it is about 7 years old now. maybe someone has done this or is willing to give it a shot and let me know their results. just wanna get some confirmation before maybe buying a new fuel pump.

[silverarrow27]

Even when my s13 had a stock fuel pump in my stock KA days, fuel would spray out from the fuel line a couple feet. I'm guessing you're referencing the lean condition from a wideband?

[omgwtf]

I am... aem uego. I figured it's gotta be a weak pump but I'd like some feedback before I buy a new one

[silverarrow27]

I swapped out my Walbro 255 lph to a DW200 yesterday, sorry I can't be of much more help. Try changing out the fuel filter first if you haven't done that in a while either. Imo, I'd run a relay to your fuel pump to give it constant 14 volts and see if that helps. Otherwise, may as well go ahead and swap out the fuel pump.

[omgwtf]

Yeah my filter is fine I checked that today and swapped it incase... thanks for the input

[derass]

Check if the wideband sensor has gone bad. Follow this video: http://m.youtube.com/watch?v=rmnxKLjM25g

I spent a lot of time chasing down what I thought was a lean condition just to find out I was getting a false reading. I replaced the sensor and readings were back to normal.

[omgwtf]

It's a few month old sensor and it's Def running lean it has 0 power. I'll check into it though thanks.

[omgwtf]

car also has on colder mornings a starting issue. i will have to start repeatedly and blip the throttle to keep it running until it will idle on its own.

[jr_ss]

Fuel pressure is solely determine by a back pressure source(FPR). If there is no back pressure, there is no fuel pressure, only volume.

They are cheap enough, buy a new one and swap it out.

[omgwtf]

so i put in a new pump and hardwired my fuel pump wiring all at the same time. the car starts way better in the cold. im still running lean under boost.... but i have decent power now. So i went out on a limb and turned the boost controller on high(19psi) and rolled into it. I was running high 15's low 16's at around 17ish psi with ZERO audible knock. Im pretty sure on 93oct i would at least hear something. That got me thinking. I know i have an exhaust leak behind my o2 sensor under the drivers seat from being low that i havent fixed. I also saw a bit of smoke from the collector above the turbo flange on the manifold. I am now wondering it i dont have a pre wideband exhaust leak which is tricking my gauge into reading lean under boost. it will spike 12:1 right when i first roll into boost then go lean. ive been wanting to do some rerouting on the piping and reclock the compressor so ill have a look at everything when i pull it all off. just gotta find time to do it. I now live in an APT and dont have my garage like i did in GA.Anyways thats what im thinking it is for now. any input is welcome.


You would think id hear knock at 16:1 at 17psi on 93 octane right?

[g14novak]

16:1 on pump gas is boom range. What are you running for mods? Upgraded turbo/injectors? I agree with false readings. Running 16:1 in boost, if the readings are true, that motor is going to burn through the pistons in no timr. Try Probably from that hole in the exhaust. Try covering it with one of those temp clamps or welding it up and see if readings are the same.

If you have a friend with an egt gauge, try borrowing it. If your actually hitting 16:1 on pump gas, your likely well over 900F (also confirming boom range). If the leak is affecting it that bad, youll see egts closer to 4-500F.

[omgwtf]

2860rs 800cc inj walbro 255 nistune z32 maf.

[Kingtal0n]

the engine will seem to run fine at 15 or 16:1 air fuel ratio, so the fact it makes "power" is of zero diagnostic value. Furthermore, it would make more power running that lean most of the time thanks to all of the additional heat left behind.

You are probably about to ruin your engine running it like that. the coincidence of a bad sensor defaulting to 16:1 during boost is incalculable. why not 9:1 or 18:1? or 12.45? or 7.67? If the sensor is truly bad, it would be just as likely to hit a random number. Does it also idle at 16:1 and drive at 12:1 or what?

[jr_ss]

Have you free air calibrated it or is it "pre calibrated" from the factory?

[omgwtf]

It's pre calibrated

[derass]

I should have mentioned earlier that I also am using the AEM UEGO.

When the sensor failed and I was getting false readings, I would roll on the throttle and the reading would go from 14.7 to lean off of the scale, showing ---, just like in the video.

You have Nistune, try adding fuel where the problem is. Did the car ever have correct AFRs?

[omgwtf]

It was running fine before. I can add gas with no change

[omgwtf]

Pretty sure is an exhaust leak at this point just no time at the moment to mess with it

[jr_ss]

Then stay out of boost until you can verify its the exhaust leak, a bad sensor and not another issue.

[omgwtf]

That's the plan