Ford_Assassin

iTrader: (4)

A few days ago I installed an AEM UEGO wideband O2 sensor/gauge and noticed that the A/F is getting to 16:1 @ 5000 RPM and goes as high as 17:1 as it gets to 6000 RPM.

After ruling out a few things I found a way to extend my manual fuel pressure gauge and sure enough when I hammer the gas while driving the fuel pressure drops pretty steadily all the way to at least 30 psi before I let off the throttle well before 6000 RPM. I just replaced the pump two months ago, its a Walbro 255. I am running a stock 2002 Camaro Z28 gas tank, I am running -6 AN stainless braided line from the tank all the way to the fuel rail. I just removed the fuel filter to see if it was a restriction, no changes.

I am having a hard time believing the pump is bad already, but I suppose its possible. I wonder if the pump is getting enough power? I am running the stock size wire, which is pretty small diameter, from the stock weatherconnecter plug all the way to the fuel pump relay. Think I should change to a larger diameter wire?

Any other ideas and/or suggestions are welcomed and thanked in advance.

Thanks again for the help.

Greekey

iTrader: (3)

You should check voltage to the the fuel pump. Also, what is your psi at idle?

Ford_Assassin

iTrader: (4)

I will check the voltage in the morning.

Fuel pressure at idle is around 60-63 psi and stays at least 58 psi while cruising and normal easy accel. The only time it drops is if I start getting past half thottle in a hurry. If I roll into it it stays around 58 psi, although I never got over 3500 RPM just cruising, I only got above 3500+ if I was getting on the throttle.

Nasty N8

iTrader: (33)

Yes voltage plays a big part and should have a hot-wire kit. What mods are on the car? Why the -6 line? Could be a # of reasons your pressure drop but start with obvious.

Ford_Assassin

iTrader: (4)

I am going to build my own hot wire kit using 8-10 gauge wire today even if it isnt the problem. I am already running a 40 amp relay for the fuel pump with the power coming from the alternator post, so now I just need to step up the power and ground wires to the pump.

All my mods are listed in my sig, its just a stock LQ4 with a mild cam. Everything else is run of mill stuff, nothing special.

Why -6 AN line? Why not -6 AN line? -6 AN is 3/8" I.D. which the same size as stock.

Nasty N8

iTrader: (33)

How are you regulating the pressure? How did you mount the pump in the Fbody tank? they need to be in the factory bucket with fuel around it at all times. The return line drains back into the bucket and the pump needs a venturi to keep the bucket full.

Ford_Assassin

iTrader: (4)

I am using the stock in-tank regulator. The tank is mounted in the same fashion that it would be in a F-Body. The pump is inside the factory bucket just like it would be if were straight from the factory. I am not running a return line since the tank has the built it regulator.

I checked the voltage on the existing wire to the pump a few mins ago, its at 12.5v at idle (wasnt able to check the voltage while driving, yet), but I also noticed that the wire is pretty warm. Not too hot that I can't hold it between my fingers, but def noticable.

Ford_Assassin

iTrader: (4)

I rewired the whole system and went ahead and swapped the pump out.

Now I have 110+ psi at the rail.

What gives?

MeentSS02

iTrader: (11)

110 psi at the rails? And you only changed the wiring? I'm not sure why that would have happened...it almost sounds like the regulator got clogged or something, but I'm not sure how possible that is.

Ford_Assassin

iTrader: (4)

No, I also swapped the pump out (as stated in my last post).

bozzhawg

110psi at the rail...? regulator is not working properly.....

I just had a walbro 255 crapped out on me after 5-6 months.....4000K miles

It was only producing 30 at idle and 40 at Wot........

I just went with a ac Delco.......EP381

The Walbro left a bad taste for now..... I then called Walbro to see about a manufactor warranty and they said you are SOL in so many words... the vender or seller takes responsibility of the warranty.... I bought it from Summit..... and you guessed it 90 days warranty only.....

So the moral to the story, you have to question a company that will not even warranty their own products... The AC Delco came with a 1 year warranty...... and all are tested before shipping....

No issues with the Delco so far...... 58 psi at idle and cruise, 60 psi at WOT

goodluck

Bozz

Nasty N8

iTrader: (33)

The Fbody still has a small return line comes out of the tank and by the filter has a "T" and returns back to the tank where the regulator can adjust the pressure...Swap kits I have had good luck with a Corvette filter regulator.

Ford_Assassin

iTrader: (4)

I think from the start I had two problems going on, first the pump was bad from the start, second the the factory in-tank regulator was also bad but because the pump wasn't pumping as much fuel as it was suppose to everything seems normal until I stomped the gas.

So, I have ordered the AN fittings I need and I will be plumbing in the ever popular Corvette filter/regulator (Wix #33737) as soon as I have the AN fittings pretty close to the tank since that is where I have the most room.

Hopefully it'll take care of my problem.

Ford_Assassin

iTrader: (4)

Installed the external filter/regulator with the new AN fittings and adapters and everything is right where it should be.

Thanks guys!!

MeentSS02

iTrader: (11)

Awesome...glad you got it figured out. It sucks when it is happening, but makes you feel pretty good when you get everything working right.