Help with Vapor lock

Discussion in 'Troubleshooting & Diagnosis' started by dph42, Feb 27, 2018.

  1. dph42

    dph42 New Member

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    Feb 26, 2018
    Update! As stated above I have narrowed my problem down to the last section of metal fuel line to the pump due to the headers heating them. A racer friend of mine told me to wrap the line with insulating tape from Lowe's. he stated it is the exact stuff you can get in the automotive section on Amazon but it's $5 instead of $25+. Here's the problem, I have spent all day trying to get the line off of the car to do it correctly and it ain't happening due to all the twists and turns both in the car and the line. There is no way to wrap on the car for the same reasons. Anyone have any other suggestions? I read somewhere in this forum where a guy had run a new line on the outside of the frame and under his upper control arm. If that gentleman reads this please contact me I would like to see how that worked out. Once again any suggestions greatly appreciated.
    Regards,
    David
     
  2. Jeep43

    Jeep43 Veteran Member

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    Mar 30, 1999
    Connecticut
    How about building a simple shield out of sheet aluminum? Or how about slitting rubber hose that has an ID the same as the metal line OD and slipping it over? Perhaps both?
     
  3. dph42

    dph42 New Member

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    Feb 26, 2018
    Well I am back. But no further along on this '70. Had some things get in the way but here is where I am at this moment. I sheathed the last section of metal line that runs buy the headers with a DEI heat sheath and even moved the line from the pump to the carb from behind the alternator and up against the block to the side of the alternator. I thought that would take care of it completely since when I bypassed the last section with rubber line on the ground the car ran until I shut it off(see earlier post). I am still in the same boat! Saturday was fairly warm and had a car buddy stop by. Told him about it and he said "no way" cuz like me he has friends running the same set up and they work. Well it ran for almost 10 minutes then the fuel boiled in the filter. Like before the manual pump was around 125 degrees by my hand held thermometer. I have a cheapy electric pump I may hook up to see if that helps even though I despise them. I am glad I am not in college because all the weeks of research have wore me out. I did learn that there is not and additive to cure this because the Blends are multiple substances and adding something else cannot take out what is causing this to happen unlike when we add Anti-Freeze to plain H2O. Once again any help would be greatly appreciated!
     
  4. Coadster32

    Coadster32 Veteran Member Lifetime Gold Member

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    Oct 2, 2013
    Milford,CT
    I rebent new metal fuel line from under the passenger door, up the frame rail curve, and then came out around the inner fender well away from the headers on my 79 camaro. Under the hood, it runs up and over the arch of the inner fender well, an back down to the pump when it gets to the front of the fender well. I didn't want to go there at first, but alot of people with regulators put them there anyway, so I said "why not". I had the same issue, fuel boiling in the filter. The route stays away from the headers considerably. I also "sleeved" it with the heat sheild tubing stuff. Problem solved.
     
  5. Zspoiler

    Zspoiler Veteran Member

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    May 6, 2012
    Federal Way, Washington
    Do you have a vented or non vented gas cap .just for laughs and giggles.?
     
  6. Coadster32

    Coadster32 Veteran Member Lifetime Gold Member

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    Oct 2, 2013
    Milford,CT
    It is a vented cap...but I also have the vent line coming from the tank open as well. I run it throught a filter to keep the gas fumes smell down....small charcoal filter.
     
  7. COPO

    COPO Veteran Member Lifetime Gold Member

    16,334
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    Sep 15, 1999
    Ontario, Canada
    Years ago I visited the local airport and bought fuel line covers that slide on the line as my shield.
     
  8. dale68z

    dale68z Veteran Member

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    May 14, 2009
    Glendale Arizona
    My 71 would boil the fuel when idling for long periods. I used moroso spark plug wire insulation on the line you insulated and the problem was solved.
    Block mounted pumps suck the fuel out of the fuel tank. Fuel under a vacuum boils very easily.
    Confirm you have no suction leaks, from the fuel pump to the tank. There are 2 rubber hose splices. The one under the passenger door and the other at the tank. Make sure the rubber is good and clamped well.
    My elcamino has an edelbrock carb. Those carbs cannot handle much more than 5# of fuel pressure. When the car was shut off the fuel pressure would raise due to under hood heat and push open the needle and seat and dump fuel in the engine. When started it had a long crank time and black smoke for a second or two.
    I solved the issue by adding a fuel filter with a bypass to the line to the carb. It bleeds fuel back to the fuel tank. I used the charcoal canister line to return the fuel to the tank. You may try using that style filter to keep the fuel moving that way it doesn't get hot enough to boil. fuel filter like this.
    http://www.gmcmhphotos.com/photos/3...fuel/p60107-3-port-fuel-filter-installed.html
     
  9. dph42

    dph42 New Member

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    Feb 26, 2018
    Well I am back to messing with this '70 again, April is a busy month when you have your own business. I appreciate all the other reply's and advice. Here is what I am gonna try and would like some input. I have purchased a filter like the one in the above pic. It is a WIX 33041 with a 3/8 in and out and a 1/4 vapor line. I plan to install it after my manual pump and before my clear filter. My car has a canister but all of that has been disconnected except the return line. The car still has the metal return line on the drivers side that goes back to the vapor separator above the tank. I think I should be able to run the vapor line over to the return and possibly bypass the separator and use the passenger side nipple on the tank. I thought about trying to use the separator but who knows how many decades it has been unused and I have enough troubles! I don't believe that it is necessary cuz I think it was a 1970 only thing anyway. If anybody has a diagram or knows how they work I would be interested anyway. Any input would be greatly appreciated. By the way this weekend I replaced the 2 line pump on my '69 with a 3 line as the car had a factory return line and the car ran until it ran out of fuel where before it had the same problem as this '70 so maybe there is hope.
    Thanks again for all the help!
    David
     
    Last edited: Apr 25, 2018
  10. dph42

    dph42 New Member

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    Feb 26, 2018
    Coadster32,
    Is it possible that you may some pics of how you ran your fuel line and how you secured them? I may have to go that route. Saturday I ran a return line off of a 3 line filter ( thanks dale68z ) using the factory return line down the passenger side and being it was in the 80's that day, the car still vapor locked in less than 10 minutes. Then to top it all off I crawled under the back to see if I had any leaks in my handy work and not only was it seeping on the drivers side EEC nipple the gas had cleaned the crud off and the nipple had been repaired with JB or something and it had let go! So now I have a new tank and sending unit on its way. I wish I was not so stubborn and would just go electric pump, but I despise them and too many others are running around fine with my same set up. Anyway Thanks everyone for you input! Now it is a quest!!!!!!!
    David
     

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