My truck was at the dealer today because I was getting a code checked out and I happened to ask if they could check my fuel pressure also.When they checked the pressure,the fuel system was leaking off when the pump was shut down.They told me that I need a new fuel pump.I said, "Are you sure".They said yes because the computer or what not said the leak was before the filter.Can the computer tell them that?They assured me that is the problem but I could've sworn reading something on here about a pressure regulator or something to that effect up at the engine side of things.I just want to be sure before I shell out cash for a new pump.By the way it's a 98 4.3.

best of my knowledge, the computer cannot tell them where a leak is unless there are pressure sensors at different spots. without seeing and testing the truck myself, i can only guess that the regulator is to blame. Easiest way to check is to pull off the little VACUUM hose from the regulator itself. if fuel comes out, then it is bad. i put vacuum in caps because if you pull the fuel line, then of course you will get fuel. replace that first then do another pressure test. This is of course assuming that it is not a returnless system, as those have no regulators. i am not sure what type of system this is, but that is how you check the regulator.

also, if i am correct, the pump when off, is just that, off. there should be residual pressure after the vehicle of shut off. residual meaning that a little might bleed off, but not all of it.

There is no way for the computer to see where the leak is. If anyone confirms this (I'm fairly sure, however), I'd suggest you change mechanics.

The early 90s Blazers were designed to bleed off pressure when not running (I'm not sure if the newer ones are too). The lines remain full, just no pressure in them, so they pressurize almost instantly.

I was working on one, and that led me around in circles for a couple hours.

As long as yours starts without excessive cranking, I'd say it's probably designed to bleed off pressure.

i agree the computer can not tell where a leak is. he said it told him it was before the filter? their taking you for a ride, dont hope on board. when the pump is off its off. the system is just releasing pressure after shut down. it is normal. this is not an episode of nightrider, our computers can not zoom in on a leak.

My computer can, but I painted it red so it has more horsepower :eek7:... that's probably not funny to anyone here, I know a guy that thinks red is the miracle color...

But about the mechanic, definately find a new one. They're either trying to cheat you, or have no clue what they're doing. :2cents:

Yea the whole leak off before the filter sounded fishy to me.I happened to go over my slip and it says,Tested fuel pressure and it will not hold it's prime.Needs a fuel module.Why I got the other story?Don't know.I had them check the pressure because when the truck is cold it fires right up.After truck has been warmed up and the engine is shut off and then you try to restart it after a couple of minutes,it cranks from 3 to 6 seconds before firing up.

Well I put a new fuel pump on and the problem has been cured.So they must have known something.I saved lots of $$$ by doing it myself.The dealer wanted $400 for the fuel pump alone,I got one on ebay for $180.:)

hope it was one of those new sealed in box kinda things. Not dissing ebay, but i am personally kinda leary of any kind of used pumps or other items of the like. Kudos on the DIY job though...good deal.

It was brand new AC Delco with warranty.

sweet!

Curious, I just replaced my fuel pump on mine, its the W engine with the 60 -65 pounds fuel pressure pump, it cost just under $80.00 at the local parts store that I have done business with for the past 40 or so years.

That was the hardest fuel pump I have ever replace, and I though the heater core was hard to change, it was easy compared to this fuel pump.

It was an easy change,cause I pulled the bed off.

It was an easy change,cause I pulled the bed off.

Hard to do that on a Blazer S-10.

My fuel pump went out on me out in the middle of the boon docks, thanks be the wife had a cell phone.

With out the cell phone we would have had a long walk, first time that I was happy for her to have a cell phone!

That sucks,I have heard they suck to do.