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Fuel Pump Trouble or ?

Discussion in 'Chevy Trucks' started by Rick Loncosky, Jul 9, 2003.

  1. Rick Loncosky

    Rick Loncosky Senior Member
    from 17557
    Messages: 102

    My nephew has a 94 Chevy K1500, which had to be towed 100 + miles because of lack of fuel, so I think? I pulled a plug, #1, and it has spark. I put a long screwdriver to the tank and I didn't here the pump come on with the the key. It cranks but won't start. It has spark, I can fill the relay kicking in when the key is turned on. I removed the air cleaner inlet to the throttle body and dumped in a little gas and it fired momentarily. Is it the pump or what? I told him to drain & drop the tank and check the pump and change fuel filter. Any other ideas? Thanks guys! Rick.
  2. CT18fireman

    CT18fireman Banned
    Messages: 2,133

    Being a 94 I would say that the pump has likely quit. He almost got ten years out of it, not bad. Pulling the tank can be easy or hard depending on rust. Make sure to do the filter and check all the lines for rust through.
  3. snowjoker

    snowjoker Senior Member
    Messages: 283

    Take a big hammer and rap on the tank a few times. My pump did the same thing and i got away like that for a couple weeks before it finally died. Also it will be easier to take the box off to do the fuel pump than dropping the tank. I dropped the tank and what a PITA. Good luck on your nephew's truck and keep us posted. I would change the filter first Mine had plugged up completely and i think that is what caused the pump to fail.
    Last edited: Jul 9, 2003
  4. wyldman

    wyldman Member
    Messages: 3,265

    Sounds pretty much like a pump.You can slightly loosen the fuel supply line (the larger one) at the back of the throttle body,and check for pressure there,when the key is turned on.If you have no pressure,then it's probably the pump.If you have pressure,it's something else.

    A few other things to check.Try cranking the engine for 10-15 secs,or until you get a good reading on the oil psi gauge.If it starts,then the relay is bad.Disconnect the wiring at the tank,and check for power on the grey wire.You should have power for 2-3 secs when key is first turned on.Check for a broken,loose or corroded ground wire at the top of the tank,or the frame rail beside the tank.If it all checks out (and your sure there is gas in it),then it's a pump.

    You can try banging on the bottom center of the tank,and you may find the pump will come to life.

    If your going to replace the pump,use only an OEM GM pump (expensive),or an aftermarket Carter pump.GM unit is a complete fuel module assy,the Carter is just a pump,which you swap into the fuel module.Carter makes the OEM GM units,it's the same part.Stay away from any others,as they don't last,and perform poorly.Get a new lock ring for the tank,and a new strainer (filter) for the pump,and a new fuel filter.

    When you go to install it,your going to find the steel lines,to rubber hose connections seized.You have two choices.Drop the tank a little,undo the lock ring (just pry and bend it out carefully as it will be rusty),and then drop the tank leaving the fuel module and lines still in the truck.You can then swap the pump and strainer,and lift the tank back in.It takes a bit of finesse,but you won't have to mess with broken lines.

    If the lines are really rusty,and you can't do the above method,then just cut the two braided rubber hoses,and disconnect the vent to drop the tank.When you get it out,cut the bubble flare ends off the fuel module.Cut the steel lines on the truck off at a decent place,and use rubber fuel line (rated for fuel injection - spec 30R9) and clamps (they also need a special band clamp,not gear clamps) to reconnect the lines.The fuel pressure line is 3/8",and the return is 5/16.I usually run the pressure line new all the way up to the filter on the frame rail,to prevent future leaks.Install your new filter,and use a new bubble flare fitting to connect to your rubber hose.They sell these repair fittings at most parts stores.You will need a 3/8 male fitting,with the longest steel pipe you can get on it.This will run back down the frame rail towards the tank,to connect to your rubber line.

    So if you going to do every thing,here is what you'll need

    1 Carter OEM pump
    1 Carter strainer
    1 Fuel filter
    4 ft 3/8" 30R9 Fuel injection hose
    4 ft 5/16" 30R9 Fuel injection hose (30R7 Fuel hose will work too)
    2 3/8" Band style hose clamps
    2 5/16" Band style hose clamps
    1 Fuel repair line with 3/8" male fuel filter fitting to steel pipe (long as possible)

    I attached a pic of the fuel repair lines below,so you can see what they look like.

    fuel lines.jpg
  5. Mike 97 SS

    Mike 97 SS Banned
    from U.S.A.
    Messages: 1,106

    Definitely a fuel problem and most definitely it is the fuel pump. I wouldnt bother lifting off the bed though, drain and drop the tank with the help of one other person. What I like to do to, that you probably dont have to do, is mark the top of the tank with chalk which way everything is pointing before removing the lock ring and pulling out the whole sending unit. Just in case when you go to drop it back in, you say to yourself, hmm which way was these lines pointing?!? Like I said you probably dont have to do this step, but I always do. Definitely put a new fuel filter too. I think an old filter that may be partially clogged makes the fuel pump work harder to push the gas through it. I probably shouldnt say this cause I bet I will regret it, but my 92 Chevy still has the original fuel pump in it with 107k miles. It probably isnt going to last much longer but Im not gonna put in a new one until this one burns out, Im curious to see how long it can go. 11 years old and still pumping is pretty impressive. :) Like someone said above, when it does go, Im getting an OEM part, nothing else. Good luck getting it done. Let us know how you made out. Mike
  6. Arc Burn

    Arc Burn PlowSite.com Addict
    Messages: 1,141

    Been there,done that with a 90' chevy 1500,same symptoms,while we started loosening the bolts to the box(which were not coming off mind you:realmad: )we noticed a bad ground wire from the pump to the frame,check the easy stuff first,then rip and tear.

    If it is the pump,have no fear,Wyldman is walking freakin Chilton manual!,I think he just guided you step by step thru the whole process:D
  7. wyldman

    wyldman Member
    Messages: 3,265

    Mike - no need to mark the location of the fuel unit,as it only goes in one way,it's idiot proof. :D When you get a pump,get a Carter from a jobber or parts house.Same pump,1/4 the price.

    Arc - I've done so many of these trucks,I could do it in my sleep.I've never had much success pulling the bed off,as it's all siezed too.A lot are work trucks,with racks,and a bed full of crap,and I don't get paid to clean em out.

    99% of the time,the lines are all rotten and siezed,so we just cut and replace,all the way to the fuel filter.The fuel filter flare nuts usually sieze onto the lines too,so when you cut the line into the filter from the pump,you can lossen the filter from the front line and just spin it off,not damaging the other line.

    Use lots of anti-sieze on the nut threads,and under the nut to the pipe.Anti sieze the new lock ring too.
  8. sonjaab

    sonjaab PlowSite.com Addict
    Messages: 1,425


    My 96 Caddy died on me one day.
    Checked for spark....YUP
    Shot some either down the throttle body...Started then died
    Disconnected fuel filter........NO fuel !
    Dropped tank..........Darn rusted broken wire !

    Rick ...where are you at ?

    Snow and salt eats up everything........But fun to PLOW tho!:yow!:
  9. Rick Loncosky

    Rick Loncosky Senior Member
    from 17557
    Messages: 102

    Wow, you guys are great. I past all this info to my nephew, he hasn't had any time yet. Mom's not happy she's on Vacation and has no wheels, so this will be done this weekend. I'm hoping he gets a quality pump. I also hope he checks for some salt corroded wires. Salt is the states & townships best friend in the winter here in Southeast PA. I'll post what they find when they find it. Thanks again, Rick.
  10. Rick Loncosky

    Rick Loncosky Senior Member
    from 17557
    Messages: 102

    I finally got a hold of my nephew. Him & his dad took the bed off and attacked from the top. It was the pump and he's running again. Thanks again for your input, Rick...............
  11. wyldman

    wyldman Member
    Messages: 3,265

    Glad to hear he got it running.
  12. Alan

    Alan PlowSite.com Addict
    Messages: 1,393

    I went so far as to cut a big "H" in the bed floor of my 89. Figured out where the tank piping went in and split the bed floor with a panel ripper. Bent the flaps up and had plenty of space to access the lock ring on top of the tank. After the repairs I used some 1/8" flat stock under the floor and pop riveted the flaps back down. nobody knew it was there under the bed liner but it saved me a bunch of money when it went out a second time and I had to get it done in a shop.