turbo_d

Ok, so I can not figure out what is wrong with my civic. It is a d16z6 with a t3/t4 turbo kit on 8 pounds right now, and it has a walbro 255lph fuel pump, and dsm 450 black tops in it. I have a fuel pressure gauge on it and whenever I get into boost it will just lean out real bad and fall on its face, and the gauge will drop a lot. I have replaced the fuel filter and that helped it a little, but I'm starting to think that it is my fuel pump. It whines whenever its warmed up and idling, but when its cold it doesn't seem to do the whole hesitating thing. I know what a normal walbro whine sounds like, and this thing is load as hell when I'm idling. Has anyone ever had any similar problems before?? I sure hope so, cuz I'm pulling my hair out trying to figure it out. Any help would be greatly appreciated.

IN VTEC

iTrader: (3)

I had a used 190lph pump and during the 1st dyno session, when the engine was loaded heavily, it would lean out. The pump was also louder than normal. I replaced it with a 255lph pump and it was quieter and fixed the lean issue.

turbo_d

So your saying that my 255 could just be faulty? I just put that stupid thing in like a week ago. You said yours was abnormally loud too? I was talking to some other dude, and he said that out of 100 that are made, 5 are faulty. I just happen to get the ****ed up one. What luck. Anyway, before I go and buy a new one, does anyone know if it could possibly be anything else.

Boosted-EH-804

Is the car tuned first thing. Do you have a wideband if so how lean?

cbustuner

Wire the walbro to a relay that goes directly to the battery.Could be an electrical issue and that will fix it. Sometimes under high load the voltage drops too much for the pump to keep up and it will lean out.Mine got louder when I wired it like this but I have never had an issue with it.

Where did you buy it from? There have been knock off walbros floating around.Other then that my only other guesses would be tune issues or the fuel pump is just junk.

turbo_d

well, my car was in the process of being tuned, and he said when it got into boost, it was just off the charts lean. He said he was dumping all kinds of fuel trying to richen it up, and it was still just off the charts lean. He had a wideband and everything tuning it with ectune. So what would I need to do to wire it up straight to the battery? That would be really easy, because my battery is in the trunk.

redlinetuning

what are your injector duty cycles?

turbo_d

I dont have any idea about that kind of stuff. My tuner knows all that stuff, but he told me that he was dumping fuel in it and it was running crazy lean. I have that fuel pressure gauge put on it and whenever I get into boost it will just drop like 40 psi. Its around 60 up until boost then like 20. I just want to try wiring it straight to the battery before I send this pump back and get a new one. I just dont want to send it back and then find out that it is something else, not the fuel pump. What else could it be????/ I'm so confused.

turbo_d

Theres no way it could be the fuel filter could it. I swaped it out, but that one might be bad too just not as bad.

redlinetuning

at 8psi, DSM450 injectors should keep up. Do you have a stock fuel pump you can use to test? If your stock fuel pump is also leaning out at boost, then it's not your pump. There's a bottleneck elsewhere.

95streetciv

I'm having an identical issue. D16z6, greddy kit 5psi, Leaning out FAST at wide open throttle boost.
Fuel pressure dropping under engine load.

So I just bought the 255 walbro to replace stock pump and fix the issue, but afterwards the issue continues exactly the same. So don't blame the walbro just yet.
Unless we both got bad pumps.

I think I'm next going to try to check voltage, and then try a new hot wire to the pump.

(never thought I'd want\need a fuel pressure guage in the dash, and now it looks like I need one for troubleshooting)

jasons9594

the walb. 255 pump is famous for failure im on 3rd one in my d-series coupe but i would replace fpr also the diafram might be bad in it and when it sees boost might be killing it or atleast try unhooking the vacuam source off it....and why the hell would u have ur fuel pressure set to 60psi? should be at like 42 max

turbo_d

I dont know exactly what its reading, but its dropping like crazy under load. My fuel press gauge is on my fuel filter, and I dont have a hood on my car, so I can see it when I'm driving. So your saying that it is possible my fpr? If I take off the vacuum, will it not do that anymore, or what will it do? Thank you for all your help, David

redlinetuning

Agreed, if you are using a stock fpr, switch that out as well. I've only been using my Walboro 255 for a couple months, so I can't say it has failed me yet. And my injector duty cycles are only at ~75% with RC550 @40psi. Boost set at 8psi and 14.8psi on boost controller.

I've seen people have 2 fuel pressure guages, 1 at the filter and another at the fuel rail by the FPR. It may be redundant, but it helps for troubleshooting problems when you do have them.

Unless you have an electronic fuel pressure guage, I wouldn't recommend putting one in the cockpit.

jasons9594

ya im running 1000cc inj. a 255 walb. and a aem fpr @15psi right now (streetable)the prob with a stock fpr is that there not able to see boost it crushed the diaphram in them if u unhook the vac signal to them the fuel pressure will basicaly be at what it is a wot (no vac.) then u can see if ur fp drops or not and if ur running a stock fpr how r u seeing 60psi of fuel pressure? maybe ur fuel pressure guage is bad ive seen that happen a lot also the engine vibration takes them out...but on another note 1000cc inj. suck *** to tune for idle in a sohc lol im ganna drop to 880cc so its more driver friendly

turbo_d

Ok, so if I take off the vacuum on the fpr it is like wot??? I can see if the fuel pressure drops once I take that vacuum off, and if it does, then what? and if it doesnt? I'm just hoping that I dont have to take my fuel pump out right now. Thanks, David

turbo_d

up

jasons9594

im saying drive it with the vacuam sorce off to see if it still drops cuz then ur fpr doesnt see boost but ur motor does

95streetciv

See... this is all starting to make sense to me... I was wondering how a vaccum connected fpr raises fuel pressure in vaccum, then vaccum suddenly becomes boost. The plunger heads the other way right? and the boost pushes the pressure lower! duh right!?

So a one-way vaccum hose insert should fix the issue right?
So how does a rising rate fpr work when they start to see boost instead of vacuum?

I'm using a stock fpr/with a vision adjustable half-cut on it, and my diaphram must be collapsing or whatever... If this is my leaning problem the whole time, I am going to kick myself.

redlinetuning

I say get rid of that half-cut FPR junk and get something halfway decent (AEM) or better (Aeromotive, etc).

95streetciv

yea, that half-cut is off my fuel rail as soon as i get home. pure junk.

95streetciv

Also make sure to plug the open vaccum nipple on the intake manifold!

In fact I'll probably take off the vaccum line on the fpr, and set my fuel pressure and just leave it static until my new fpr arrives in the mail.

i don't need my fuel pressure jumping around anyway right?

turbo_d - lets try this and report back our results.

turbo_d

Ok, so I took off the vacuum and plugged the intake port and it is still doing this gay ****. I talked to my tuner a couple minutes ago, and he said he's never seed a honda oem fpr go bad. He just tuned a dudes car and made 400 hp with the stock one. IDK what else it could be besides the fuel pump. So how do I go about wiring my fuel pump straight up to the battery. Something to do with a relay? Any help would be appreciated.

95streetciv

bummer man, I'm still hoping my problem is the fpr.

like you, i switched my fuel filter (twice) and my pump.

To wire your pump, I would check the voltage that the current wiring is supplying before doing anything. not sure what its supposed to be, but get a reading anyway.

The relay is to give the pump power only when the ignition key is on. So your battery doesn't drain when your parked and the car is off.
you could wire a manual switch just to test with, but if it does fix it then you should do the whole relay wiring because you will forget to turn it off when you get somewhere and come back to a dead battery.

jasons9594

depends on the brand but most have a 1 to 1 boost refrance