Ferocity02

iTrader: (59)

So I was driving home from work today and didn't get more than 1/4 mile before I noticed that my wideband was reading way lean, almost beyond its limits. However, I have semi-open loop enabled, and as long as I was driving at a point where the PCM was commanding EQR=1.0, the STFT's were able to account for the low fuel pressure. When EQR is not 1.0 then it is in open-loop and it goes WAY lean. This was a huge issue since I have lean cruise enabled from 1200-2200 RPM at partial throttle, so it commands an EQR<1.0 and then goes lean.

I pulled over and saw that my fuel pressure at the rail was about 25psi at idle. I removed the vacuum line to the regulator and the fuel pressure didn't change. I had to run a few errands and when I got home about an hour and 25 miles later the fuel pressure at idle was about 20psi. When I turn the key off the fuel pressure instantly drops to zero.

About two months ago I noticed that my fuel system wasn't holding pressure. After engine off it would drop to zero in a matter of minutes. It used to take a long time for the pressure to drop, even after several hours it may have only dropped like 10psi.

So would this be a bad pump or a bad pressure regulator? The pump is a Walbro 255 that has about 17k miles on it installed almost 2 years ago. FPR is stock. Or perhaps the fuel line at the pump partially burst?

LS1TRUCKGUY

iTrader: (7)

What type of hose did you use when you plumbed the walbro in there?

Atomic

iTrader: (42)

Fuel pump problem...

Ferocity02

iTrader: (59)

It was a submersible one from Gates, and really damn expensive, like $20 for 1.5ft.

Ferocity02

iTrader: (59)

Why do you say this instead of the regulator?

Atomic

iTrader: (42)

Regulators do not break often.

BlackGMC

iTrader: (31)

Sounds like the pump to me too. How low have you let your gas tank get lately?

Ferocity02

iTrader: (59)

I usually fill it up with 2-4 gallons remaining, 26 gal tank.

03sierraslt

iTrader: (22)

So in other words E.

trxmxzx

iTrader: (7)

Might be pretty dumb to mention but my filter threw me off once like this

My pumps in both my trucks with the 255 don't hold pressure- when they did it was for the first 6000 miles. My one has about 5 years the other 2 years