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Fuel Pump Problem?? *UPDATE*

Discussion in 'The Garage' started by docgab, Jun 22, 2003.

  1. docgab

    docgab 1/2 ton status Premium Member

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    Well hello again all. Geez I'm sorry for all the questions as of late, but the big ugly beast is wearing out it seems. /forums/images/graemlins/wink.gif OK here's the deal. Started the truck after playing some ball and drove about a mile to get some food. About half way back the truck started to bog out. It seemed to be starving for fuel. I could put it in nuetral and coast for a bit and then put it back into park and it would do fine for 30 secs or so then start it again. I shut the motor down and checked all my fuel lines etc. Started it back up and it was good for about another mile then it started again. It finally died on me and had a funky smell, kinda like after a backfire. I let it sit for about 5 mins and was able to get it started and it was good for about 200 yards or so. I shut it down and here I am now.

    I had to put some gas in from a gas can and forgot to put the gas cap back on. It sat for a day and a half until I drove it today. I stopped for gas and noticed the dumba** I am for not putting the cap back on. While I was playing ball, for some reason I stuffed a sock in the filler hole and of course forgot to take it out for the drive home. Don't know if that would have caused any problems.

    After all that, should I be thinking fuel pump? Could it be intermittant like that? What else should I look for? It was given a tune up a month ago or so (new plugs, wires, cap, rotor, fuel filter). I am searching as we speak, but as always, all ideas appreciated!!

    Truck is a '78 K5, no EGR, no cat, 350 etc.
     
  2. dyeager535

    dyeager535 1 ton status Premium Member

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    Re: Fuel Pump Problem??

    When my mech. fuel pump died, it gave me a bit of a warning, but we are talking about 5 miles between onset of symptoms, and complete failure.

    Almost sounds like a float issue if letting it sit helps, and it backfired...sometimes too much fuel will spill out, flooding the engine. Can cause backfires.

    Lots of reasons this could happen though, I'd kind of doubt fuel pump. You can check the carb (at least rochester) by taking the air cleaner off, (while the vehicle is off) making sure the choke is fully open, look down the primary venturi's, and operate the throttle with your hand. If you see fuel squirting out, probably at least two full strong squirts, you are getting fuel to the carb.

    After sitting for a day this is not a good test, but something to look at if it dies on you again. If not getting fuel is the problem, due to fuel pump, the carb will be dry. (no accelerator pump shot)
     
  3. Can Can

    Can Can Pusher Man Staff Member Super Moderator

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    Re: Fuel Pump Problem??

    It kinda sounds like a vapor lock issue to me. Like Dorian said, check to see if you're getting gas at the carb after one of these episodes. From there you're just going to have to troubleshoot your way through the fuel system.

    Start with the easy things first(like the fuel filter(s)). If everything checks out I would recommend getting inside the carb and taking a good look at your needle and seat/float to amke sure they're OK. It could easily be a carb problem.

    There's one other thing I think might be worth mentioning- did you fill your truck up with a jerry can because you ran out of gas? How new was the gas in the can? You may have sucked some crud from the bottom of the gas tank into your fuel system when you ran her empty, or you may have put some bad gas in the tank. Either of these could cause your truck to run like shite, too.

    Keep us updated, brother!!!
     
  4. docgab

    docgab 1/2 ton status Premium Member

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    Re: Fuel Pump Problem??

    [ QUOTE ]
    Almost sounds like a float issue if letting it sit helps, and it backfired...sometimes too much fuel will spill out, flooding the engine. Can cause backfires.

    [/ QUOTE ]

    It never did backfire, it just gave off a smell like after a backfire. I was easy on the gas when it was stalling/bogging out. It has been running great since I bought it (about 4 months ago). Would a float problem tend to just pop up?

    [ QUOTE ]
    Lots of reasons this could happen though, I'd kind of doubt fuel pump. You can check the carb (at least rochester) by taking the air cleaner off, (while the vehicle is off) making sure the choke is fully open, look down the primary venturi's, and operate the throttle with your hand. If you see fuel squirting out, probably at least two full strong squirts, you are getting fuel to the carb.

    [/ QUOTE ]

    Man I was about there earlier. I was getting desperate and had removed the air cleaner and did operate the throttle. I wasn't looking down the carb, but I did hear stuff going on in the carb. I will try that tomorrow if I get it going again. My chooke isn't hooked up, is this test still valid? If it was a fuel pump which was going bad and the problem was intermittant though, would I see the gas being injected?

    [ QUOTE ]
    After sitting for a day this is not a good test, but something to look at if it dies on you again. If not getting fuel is the problem, due to fuel pump, the carb will be dry. (no accelerator pump shot)

    [/ QUOTE ]

    Thanks for your input! I will give this a try tomorrow!
     
  5. blasterD

    blasterD 1/2 ton status

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    Re: Fuel Pump Problem??

    If you are getting fuel at the carb you may bave gotten some bad/dirty/wet gas. I have seen similar symptoms from water in the fuel of crud gumming up the carb
     
  6. dyeager535

    dyeager535 1 ton status Premium Member

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    Re: Fuel Pump Problem??

    Yeah I just meant that smell be because the engine is getting too much gas.

    Choke doesn't matter if it's hooked up for that "test", since the only reason you need to move the blade is so that you can see clearly /forums/images/graemlins/smile.gif

    And theoretically, if the float is stuck shut, you won't see fuel in the carb either, so you'd have to then make sure the fuel pump moves fuel when the engine cranks. (disconnect the line going to the carb and check)

    From my experience, eventually a float stuck closed will be forced open if the pump is working ok, but it can take some time, or luck.
     
  7. Triaged

    Triaged 1/2 ton status

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    Re: Fuel Pump Problem??

    My truck had the same symptoms. It was a bad filter. Just buy a new one. They are only $1.50. There is no use "checking it" when it is that cheep. Just replace the thing.

    Stupid me left the spare filter at home so I just took it out as a temp fix.
     
  8. boggerless

    boggerless 1 ton status Premium Member

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    Re: Fuel Pump Problem??

    tot i know this sucks but after everything else, if it still does it. check the filter in the tank.i had a 75 chevy 4 door ,454.t 400 trans. that did the same thing.that stupid little tooth paste looking filter was packed. i could only go about a 1/4 mile and it would die.i'd coast a bit and put it neutral and start it back up and go a 1/4 mile more.it would idle o.k. the worst part was the tank was full when i changed it /forums/images/graemlins/k5.gif
     
  9. docgab

    docgab 1/2 ton status Premium Member

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    OK. Here's what went on today. The PO had put an inline fuel filter in after the fuel pump but before the carb. This was changed about 3 weeks ago. I pulled the filter out of the carb and it didn't look too bad. I then tried to suck air through it and/or blow air through it to no avail. Obviously a bad filter right? I got the truck started after some serious cussing and pedal pumping. It had a VERY fast idle which couldn't be adjusted by the screw on the front of the Q-jet. I ran it home with no problems other than the fast idle. I then drove it about half a mile, started up a hill and it wanted to bog again, I put it in neutral for a few secs, popped it in drive, and then the idle went back to normal and was able to be adjusted! I then drove it about 6 miles and had one little incident of it wanting to bog down on a slight hill but over all it was good. The trip home was the same thing, I hit a hill and it wanted to bog out. Not every hill, just hills towards the end of my trip.

    I am going to replace the carb filter and I think the inline filter as well as I had just recently dropped my tank and it was pretty dang dirty. I had to get it together again in short time so I didn't get to clean it out like I should have (I am finding that when you do a half assed job like this you get half assed results).

    Another major question I have now is; why would my idle be so screwed up and not be able to be adjusted, then all of a sudden work again? I gotta get me that rochester book!! agh! Thanks again guys and gals. /forums/images/graemlins/grin.gif
     
  10. docgab

    docgab 1/2 ton status Premium Member

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    Re: Fuel Pump Problem??

    [ QUOTE ]
    It kinda sounds like a vapor lock issue to me. Like Dorian said, check to see if you're getting gas at the carb after one of these episodes. From there you're just going to have to troubleshoot your way through the fuel system.

    [/ QUOTE ]


    Once I removed my carb fuel filter I was getting gas to the carb. I wasn't able to check it before. I am still having problems although nowhere near as bad.

    [ QUOTE ]
    Start with the easy things first(like the fuel filter(s)). If everything checks out I would recommend getting inside the carb and taking a good look at your needle and seat/float to amke sure they're OK. It could easily be a carb problem.


    [/ QUOTE ]

    Please see my post below about todays findings. I think a carb problem might just be what's going on in addition to my bad filter.

    [ QUOTE ]
    There's one other thing I think might be worth mentioning- did you fill your truck up with a jerry can because you ran out of gas? How new was the gas in the can? You may have sucked some crud from the bottom of the gas tank into your fuel system when you ran her empty, or you may have put some bad gas in the tank. Either of these could cause your truck to run like shite, too.

    Keep us updated, brother!!!

    [/ QUOTE ]

    I filled my truck out of the can as I had to drop my tank and siphoned about 7 gallons into cans. I then refilled from these cans.
    The gas was from just a few days before and I had a bottle of fuel system cleaner in it as well. My tank was very dirty though and like a bonehead I was in a hurry to get in back together and so didn't clean it like I should have. /forums/images/graemlins/angryfire.gif I am going to replace the carb filter and the inline filter. Perhaps I should drop the tank again and clean it out properly? Waddya think? Thanks much for your input! /forums/images/graemlins/thumb.gif
     
  11. docgab

    docgab 1/2 ton status Premium Member

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    Re: Fuel Pump Problem??

    First off, thanks again to all who have replied. Your input has given me a direction to go and the confidence to deal with it on my own as opposed to paying someone to do it for me!! /forums/images/graemlins/thumb.gif

    [ QUOTE ]
    tot i know this sucks but after everything else, if it still does it. check the filter in the tank.i had a 75 chevy 4 door ,454.t 400 trans. that did the same thing.that stupid little tooth paste looking filter was packed. i could only go about a 1/4 mile and it would die.i'd coast a bit and put it neutral and start it back up and go a 1/4 mile more.it would idle o.k. the worst part was the tank was full when i changed it /forums/images/graemlins/k5.gif

    [/ QUOTE ]

    I think this might be very valid. I had recently dropped my tank and it was pretty dang dirty and I didn't clean it correctly. I guess I should drop the tank again and do the job right this time. Good timing as I am down to below a 1/4 tank!!
     
  12. Can Can

    Can Can Pusher Man Staff Member Super Moderator

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    First of all, get rid of that inline filter. It's probably been causing a fuel restriction since you bought the truck. If you make a habit of regularly changing out the in-carb fuel filter there's no need for the second filter in the system.

    Now, back to the problem:

    Have you ever heard an engine just about to run out of gas? Quite often it will run at an abnormally high idle right before it quits. The fast idle condition happens because the motor is sucking in gas fumes as opposed to liquid and because it doesn't have to mixed before it enters the carb the engine runs a lot easier for the final few seconds.

    This leads me to believe that your truck had a fuel restriction that was sucking in JUST enough gas fumes to keep the truck running. Going up the hill caused you to put load on the engine and demanded more fuel than was available from your restricted fuel system, which is what caused the truck to bog out.

    I'm willing to bet that the reason it cleared up is that the piece of crud that was causing the blockage finally got worked out of the system and that's why your idle returned to normal.

    Now to the cause: When you dropped your admittedly dirty tank, you stirred up a lot of sediment that had collected at the bottom. When you drained the tank all the crud got washed around and after you refilled your tank with the same gas it didn't have a chance to settle back to the bottom. Think about how long it took for all that junk to build up!!!!!

    After reading your update I'm almost positive the problem isn't in the carb, although I'm sure it wouldn't hurt to take it apart and take a close look at your needle and seat for signs of cruddy accumulation. I'm willing to bet that you'll be going through a few filters in the next little while. Keep your tools and a couple of filters in your truck in the meantime in case the symptoms pop up again.
     
  13. docgab

    docgab 1/2 ton status Premium Member

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    Great post! Thanks much for your help. I know exactly what you mean about running out of gas and the engine running fast, my weedeater does it too. It's really nice for the few seconds it happens, I think I could cut down a freaking tree! /forums/images/graemlins/wink.gif I'm gonna do like you suggest and get rid of the inline filter although I can't get a hard line from the pump to the carb just yet. I'll run the fuel hose for now and get the hard line soon. Once again, thanks for your help/input!! /forums/images/graemlins/thumb.gif /forums/images/graemlins/thumb.gif
     
  14. Can Can

    Can Can Pusher Man Staff Member Super Moderator

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    No problem, brother!!! /forums/images/graemlins/thumb.gif

    I'm glad I was able to help.
     

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