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View Full Version : quick question about fuel injection/electric fuel pumps


98tadriver
12-24-2007, 08:59 PM
ok now first of all, i didnt touch anything else on my moms 97 blazer lol. its been having some problems starting lately. i figured it might be the fuel pump going bad. So, with the key on, i pushed on the schrader valve on the fuel rail/line under the hood, and only a lil bit of fuel trickled out and nothing more. isnt there supposed to be a lil more pressure than that, and keep on spraying out?

some problems-

its misfiring, since the ses light is blinking and feels like a dog when i try to accelerate.

me and her b/f changed the timing chain and gears the other day since it has 160k on it. it didnt jump time or anything But its still doing the same crap.

as far as the code reader went, all it said was P0300 random/multiple cylinder misfire. i havent scanned the car today, since i dont have my code reader with me.

fuel filter is new, tune up was recent and it was running fine after that.
It will only start right away if i pour a lil fuel into the TB.

bubba428
12-24-2007, 09:06 PM
should be betwine 40-50psi the sending unit assembly is a weak link on them...unfortunately they aren't cheap. fuel filter is also a good thing to check

98tadriver
12-24-2007, 09:08 PM
looks like i will be getting a Fuel pressure gauge and testing for pressure sometime. i wonder if any auto parts stores are open tomorrow lol

bubba428
12-24-2007, 09:11 PM
I don't think so...If you find the pressure regulator on the jimmy and disconnect and block the vacuum line that will tell you if is a pressure issue or not. does it run?

98tadriver
12-24-2007, 09:50 PM
its a blazer!!!!!! and it will start when i pour some gas in the TB but doesnt run too good when im on the throttle

bubba428
12-24-2007, 09:57 PM
SAME THING!!!!!!!!! a friend of mine has a jimmy that had the same problem...it was the fuel pump(just checked advance for ya...$289 ouch) also you should check the fuel pump fuse, or relay

NJSPEEDER
12-24-2007, 10:47 PM
sounds like the pump is going/went bad. very easy to replace in the s-series trucks.

98tadriver
12-25-2007, 11:48 AM
I'll have to check the wiring schematic to see where the fuelpump fuse and relay is. i dont recall seeing any fuse boxes under the hood. and i dont think i saw a fuel pump fuse in the cabin fuse box.

WildBillyT
12-25-2007, 12:17 PM
Jimmys don't have that stupid ass fuel pump resistor that Grand Prixs do, do they?

98tadriver
12-28-2007, 04:58 PM
Jimmys don't have that stupid ass fuel pump resistor that Grand Prixs do, do they?


heck if i know. lol im going to install the walbro 255 thats doing nothing but sitting here.

bubba428
12-28-2007, 05:38 PM
heck if i know. lol im going to install the walbro 255 thats doing nothing but sitting here.

the fuel pump on the blazer IS NOT removable from the sending unit IIRC