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Engine misses update / Tank removal help

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Blazer79, May 15, 2000.

  1. Blazer79

    Blazer79 1/2 ton status

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    Engine Misses:

    A while ago I posted about the engine misses. I replaced everything in the ignition: New Summit distributor, New MSD red wires, New ACDelco Spark plugs. I went out for a long trip wishing the best, but it happened again. It started to miss, only this time it was worst: the engine stopped completely.

    I cranked it for a while, but nothing. I opened the hood with a big question mark on my face. I had someone else crank it for me, and finally found it: I saw through my glass fuel filter that there was no fuel! I quickly unscrewed it and only a few shots of fuel came when cranking it. After about 45 minutes everything had cooled down and it worked again, so I was able to drive back home. Now I'm pretty sure it's the fuel pump. I ordered a new Holley from Summit, and it will arrive any time now.

    Tank Removal:

    Now I want to be completely safe that none of this will happen again, I want to remove the fuel tank and wash it, and if possible, clean the fuel line and pickup inside. Is this possible? How's the best way to go with this?

    I have the basic idea of how to remove the tank, but any tip from anyone who has actually done this will be really helpful.

    Thanks guys. I know you will help me.

    <font color=black>//////
    What the heck!...Drive it like gas is $0.50/gal!!!
    </font color=black>[​IMG]
     
  2. jarheadk5

    jarheadk5 1/2 ton status

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    If I'm wrong, someone please correct me, but that sounds a lot like VAPOR LOCK to me. The fuel line may be routed close to something quite hot, and the gasoline is literally vaporizing in the lines before it gets to your carb. If no one shoots down my diagnosis, I suggest getting some heat sleeve and finding the hot spots.

    [​IMG] Semper Maintenance!
    [​IMG] So many ideas, so little money...
     
  3. jimmyjack

    jimmyjack 1/2 ton status

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    I used to have an old Chevy 4x4 with a six cylinder that would vapor lock. An old man told me to put wooden clothespins on the metal fuel line near the valve cover. It never happened again. Apparently they would help dissapate the heat. An awesome cheap fix!
     
  4. Todd78/87

    Todd78/87 1/2 ton status

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    Yeah,, I think I'll go with Jarhead on this one. If you have a mechanical fuel pump,, it would never be affected by heat and quite working, like electronics can. It either works or it doesn't. If you have an electric pump, is it in the tank? If so, that sure wouldn't quit because of heat. If it got that hot in your tank,, you wouldn't be here now[​IMG]. If you have an electric one and it's under your hood,, then Yes,, it could fail because of heat and start working again when it cools down.

    Todd 78/87[​IMG]
    [​IMG]
    Alaska Bound
     
  5. Eagle86K5

    Eagle86K5 1/2 ton status

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    Ah, but you might rethink that, while working for Northern Telecom In D.C. a few years back for the company car they gave me a Chevy Citation. It developed the very same thing the Blazer did, would get hot and quit, they replaced everything including the vacuum pump to no avail, till one smart mechanic noticed no fuel flow once hot, he removed the tank and replaced the pump and it ran like a new one.
    It is not that it gets that hot as much as it is the bearing sieze when it gets warm. This was proved when he applied 12vdc to it out in the open, it started to run good then slowly wound down till it quit completely. There is a bulletin out from Chevy on it ...

    <font color=green>[​IMG]Eagle86K5[​IMG]<font color=red>
    Masonry...It's a Good Thing
    2B1ASK1
     
  6. jarheadk5

    jarheadk5 1/2 ton status

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    Oh man, I even posted about that a while back, Eagle!! My Trans Am did that, and my Cutlass did it too! Keeping 1/2 tank or more ensures in-tank fuel pump health on GM's. I forgot all about that!

    Now, what else did I forget...?

    [​IMG] Semper Maintenance!
    [​IMG] So many ideas, so little money...
     
  7. Eagle86K5

    Eagle86K5 1/2 ton status

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    Not a problem Marine...heck you have slept since then...at ease....grab a cold one...retired railroad tracks said it...

    <font color=green>[​IMG]Eagle86K5[​IMG]<font color=red>
    Masonry...It's a Good Thing
    2B1ASK1
     
  8. jarheadk5

    jarheadk5 1/2 ton status

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    Aye, sir. (Hand salute; about face; forward march)[​IMG]

    BTW, nice 262 patch. I've got one of their tactical patches somewhere from when I was on the 31st (Thirty-worst) MEU with them in Okinawa. In '94, they had a Phrog with a bunch of skin patches that had names and dates from Nam etched into them. Over 8000 hrs. on the airframe...I wonder if you had time on it...

    [​IMG] Semper Maintenance!
    [​IMG] So many ideas, so little money...
     
  9. Eagle86K5

    Eagle86K5 1/2 ton status

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    Flew a bunch of supply and medivac runs with them and 261. Was with 262 in Hawaii at Kaneohe bay for 2 years. Used to jump out of the back of them with the K-Bay jump club...
    He Low...Hi lo...twist and turn...crash and burn....uurahhh

    <font color=green>[​IMG]Eagle86K5[​IMG]<font color=red>
    Masonry...It's a Good Thing
    2B1ASK1
     
  10. Todd78/87

    Todd78/87 1/2 ton status

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    Thanks for the insight, Big Guy,,, You're right, I didn't think of bearing sieze.

    Todd 78/87[​IMG]
    [​IMG]
    Alaska Bound
     
  11. Blazer79

    Blazer79 1/2 ton status

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    Sorry I didn't include all the info. It's a mechanical pump on the passenger side of the engine. I mentioned removing the tank just to be safe and remove any dirt that may have built up in there after 20 years of duty.

    Now I'm worried. Are you guys telling me the problem won't go away after the new fuel pump is installed?! The strange thing is that the problem started back in October when it still had the original routing of the fuel lines and I didn't have headers. In December I installed headers and in January a new carb & intake and installed new fuel line from pump to carb. I used a braided steel dress-up kit which is supposed to cool the lines a bit. I even routed the line near the 'cool' line of the A/C so that the A/C would cool a little bit when used.

    The new pump arrives on friday anyway. What would you guys do in my place?

    <font color=black>//////
    What the heck!...Drive it like gas is $0.50/gal!!!
    </font color=black>[​IMG]
     
  12. Blazer79

    Blazer79 1/2 ton status

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    Eagle: does the bearing seize happen on a mechanical pump on the engine?

    <font color=black>//////
    What the heck!...Drive it like gas is $0.50/gal!!!
    </font color=black>[​IMG]
     
  13. Eagle86K5

    Eagle86K5 1/2 ton status

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    The only thing I know to go wrong on the mechanical pump bolted to the engine is the diaphram going bad. The one on my Blazer did go bad...but not all at once, there was a period of about 2 weeks where all of a sudden the engine would loose power and I would pump the pedal and it would come right back, then I began to smell gas and found the cannister overflowing with gas. Seems the pump was pushing more back then to the carb. Finally it just went. I replaced it and it started right up and ran great. I took the old one apart for the education and the diaphram did have a tear in it.

    <font color=green>[​IMG]Eagle86K5[​IMG]<font color=red>
    Masonry...It's a Good Thing
    2B1ASK1
     
  14. jarheadk5

    jarheadk5 1/2 ton status

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    Hey Eagle, check private msg please...

    [​IMG] Semper Maintenance!
    [​IMG] So many ideas, so little money...
     
  15. coopertwpk

    coopertwpk 1/2 ton status

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    Vapor lock happens to mechanical fuel pumps not electric with electric your pumping cold fuel while manual is on a hot motor.
     
  16. Blazer79

    Blazer79 1/2 ton status

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    So, Any do\'s and don\'ts for tank removal?

    Anything to make it as painless as possible?

    Thanks guys.

    <font color=black>//////
    What the heck!...Drive it like gas is $0.50/gal!!!
    </font color=black>[​IMG]
     
  17. Eagle86K5

    Eagle86K5 1/2 ton status

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    Porsche 914's have electric fuel pumps that provide 28-31 lbs pressure to the fuel injection system, and believe me in the middle of a nice hot Virginia summer it will vaperlock.

    <font color=green>[​IMG]Eagle86K5[​IMG]<font color=red>
    Masonry...It's a Good Thing
    2B1ASK1
     
  18. Eric

    Eric Registered Member

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    Sounds like vapor lock to me. Happened to me last year in my 68 camaro whenever it got hot out.

    Things to try:
    #1) Look down in the carb when it happens, you may see gasoline bubbling like hell, if it is the internal pressure is not allowing the gasoline to drop/suck down into the intake.
    #2) Try to start the truck while keeping the gas pedal to the floor (to give the engine a nice cold shot of fuel). Give it a good couple cranks and see if she fires. If she does fire (and possibly stumbles until the lines and filter cool off), vapor lock is most likely the culprit.
    #3) I purchased some aluminum wrapped plastic tubing from Summit Racing for ~$20 and wrapped everything from the carb lines to the fuel filter up to the mechanical fuel pump. No problem since.
    #4) You may need to re-route your fuel lines and filter all together. Keep them away from the heat.

    Best of luck...



    One eyed super fly- watch out!
    86 K5 Blazer
     
  19. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    Well first thing to check is the lines. You have a glass filter so my bet is the line is cut off at the pump and rubber hose up the rest of the way. Is that line close the the exhaust or up against the water pump or anything else hot? Get it moved with some air space around it including keeping it off the intake manifold. Next check to do is the passenger side frame rail. The fuel lines run there and see if the exhaust is up close to them.
    Also try this...remove the fuel cap...if something is not right with the Evap stuff you could be creating alot of vacum in the tank that the pump can't overcome. Possibly the can is bad or the lines are hooked up wrong.
    Last thing...NO PUMP IN THE FUEL TANK. Only the FI version got that. If you look there is only 1 wire going to the tank and thats for the Gas gage. Now there may be still a reason to drop the tank. Water. If you have water in the tank and it gets in the fuel line it will boil quicker than the fuel and could cause the vapor lock problem. Try some line dry next tank full.
    Last thing is to make sure the lines are not restricted in any way like a dent in the hard line or the hoses are too tight of a bend.
    I would still toss a pump on it and keep the old as a spare. Pumps for that engine are like $12 at Autozone.

    Diging it in the dirt with my K5's
    Grim-Reaper
     
  20. Burt4x4

    Burt4x4 3/4 ton status

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    Sence the fuel pump is in the mail goahead and replace it, if it doesn't solve your problem then keep the old one in your trail box for future trail repairs! Make sure your fuel lines comming up from your pump are in front of your motor that way the wind and fan will help keep the heat away from the line! Next if you are gonna tackel the gas tank sanario you may whant to consider getting a new polyethelane (sp?) tank, no more rust EVER!! My tank rusted from the inside out then replaced with the poly and my filters still look new!
    Good luck

    Rock ON![​IMG] 72 K5 [​IMG] Led Zeppelin
     

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