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My rig feels like its running out of gas when there is still 2 gallons in tank, any ideas?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by shum1, Nov 30, 2000.

  1. shum1

    shum1 1/2 ton status

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    Well I'm not actually done diagnosing this problem but this is what has happend so far. Gauge reads 1/8 of a tank. Engine idles but bogs and stalls when I punch it. Removed gas cap and there was tremenous suction of air. Refueled, put heat and techron in there and it ran fine until it got to 1/8 again, same problem. Put gas in, and it runs again. This sounds like I ran out of gas but my suburban has a 37 gallon tank and It took only 35 to fill it. My guage has worked fine until now. Could there be a venting problem leading to much vacum in the tank thus causing problems for the fuel pump? Where should I begin to diagnose the fuel gauge? Any other suggestions? A friend of mine had the same problem with his blazer and never figured it out. I have a 1990 350 tbi. Thanks.
     
  2. 90K5

    90K5 1/2 ton status

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    Mine does the same thing. Its probably because of the small amount of gas in the tank, sometimes no gas goes in the fuel line for a small amount of time, and it seems like its running out. The best way to fix this IMHO is to not wait so long to fill it up.

    90K5
     
  3. Stephen

    Stephen 1/2 ton status Moderator Vendor

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    I have an add on EFI set up and it only runs reliably down to about 5-7 gal in a 31 gal tank. Mine is an 82 tank with no baffles. I can watch the fuel pressure gauge and tell just how the tank is sloshing, example, I have to be careful cornering when it's low on fuel because it runs out RIGHT NOW! BUT, it ran fine to almost empty (1-2 gal left) with a carb on it, leading me to believe carbs run on the fuel in the bowls a lot more than we think. A carb can take a minute or more to run out of gas when the fuel pump is turned off, so you go around a corner and lose fuel in the pickup at the tank and never notice it as long as you cover the pickup back up within that minute or so. With EFI, as soon as the pickup is uncovered, they suck air and you're done.
    I'd have to agree on the fix, don't let it get that low.
    SW

    SW-ORD
     
  4. blazen91

    blazen91 1/2 ton status

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    Fuel injection requires constant line presure.Example- With a carb, the fuel pump can stop and the engine will run untill the bowl is empty. Fuel injection, the pump stops, the line presure goes away and the engine stops. What is happening with you is, the pump is sucking air, thus lossing line presure. Solution- Gas up at when the gauge says 1/4 and the problem is solved.

    blazen91
    Protect the land FOR the people
    <font color=red>Not FROM the people</font color=red>
     
  5. Glenn

    Glenn Registered Member

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    Mine does that to but I have more gas than you in it. When I take sharp turns it starts to buck and quit. This happend after I put a new fuel pump in the tank. I guess I screwed it up somehow and it is to high. My gas guage is broken so thats when I know when it is time to fill it up.:) Works out good for me.
     
  6. reddog64

    reddog64 1/2 ton status

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    Um... Gas is only 1.50 a gallon... Put some gas in the tank...

    Um... yes officer I know it's too big...
     
  7. DMK

    DMK 1/2 ton status

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    With tbi you should keep tank at least 1/4 full to keep fuel pump sumurged. The fuel keeps the fuel ppump lubricated. Running fuel tank constantly low will shorten fuel pump life. Just my .02 My 89 did the same thing when low on fuel.
     
  8. 6.2Blazer

    6.2Blazer 1/2 ton status

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    I honestly don't think you have any problems except for the fact that you are running out of gas. Only 2 gallons in a 37 gallon tank is nothing, the fuel level is maybe only an inch deep at that point and the pump just can't get enough fuel. It would probably idle fine because it doesn't need much fuel to do so, but when you punch it you have the combination of needing a lot more fuel plus the small amount of fuel that is left is being sloshed to the back and further depleting what is available for the pump to pick up.

    In other words, just keep more fuel in the tank..........
     
  9. Pookster

    Pookster 1/2 ton status

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    Man, Im jelous. My fuel tank is only 24 gallons. Then again, I have a class III hitch in the back. My fuel gauge is messed up to. Says I have a quarter left, when I have like 1 gallon left.
     
  10. I have always treated my truck as empty when it reached 1/4 tank on the gauge. This has worked for me so far

    '84 K5

    Chevy in my blood.
     
  11. Blazer79

    Blazer79 1/2 ton status

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    My brother has a Camaro with TPI. He says his fuel pump is huge and holds about a gallon inside. If yours is the same, then that leaves you with very little gas left on the tank. He always has trouble turning when running less than 1/4.

    <font color=blue>//////
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  12. Blue85

    Blue85 Troll Premium Member

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    If you really wanted to to be able to suck the tank dry, you could get one of those race car pickups for the fuel pump. It is weighted or something and moves the fuel intake hose around in the tank in the same direction that the fuel goes when you corner, brake or accelerate. When you get to the very bottom of the tank, you will usually need to replace your fuel filter afterwards, since you will then suck up a lot of the crud that has layed dormant on the bottom of your tank for a long time.

    However, in tank pumps are cooled by the gasoline, so it is best to not run around too much with the tank real low.

    35 gallons to fill means that the pump was basically uncovered.

    "They tell me that you can make it to work without big tires. I'm still not convinced."
     
  13. shum1

    shum1 1/2 ton status

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    Thanks everyone for the helpful responses!
     
  14. OFFRDK5

    OFFRDK5 1/2 ton status Premium Member

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    I just watch my odometer and at about 300 mi I fill er up. Since I don't have a fuel guage I have to do it that way...and also since its Diesel I don't think I want to have to deal with an empty fuel system!!!!

    SK-15
    J**P...it's whats for dinner!
    http://SK-15.coloradok5.com
     
  15. mich89k5

    mich89k5 Registered Member

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    hey Reddog,
    You're OPECS and the big oil companies dream consumer. You shrug off a 50% increase in price in less than a year. I hope you were kidding. I'll be happy when gas is down to $1.20 and that's still about 20% increase not to mention all the months that they got us for near $2.00. Even if you're rich you can still complain on behalf of the middle working class.

    Mich89K5
     
  16. shum1

    shum1 1/2 ton status

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    Well, to make matters worse my tripometer dosent work, my odometer does but its kind of a pain writing it down and trying to remember, any suggestions of where I should look for a new spedometer/tripometer?
     

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