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Thread: Cleaning the Fuel System

  1. #11
    Senior Member Bitsyncmaster's Avatar
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    Quote Originally Posted by AZ-D View Post
    Can I disconnect the hard line at the fuel filter and jump the RPM relay to pull fresh gas through the line and see how it comes out? Or is there some other version of that to get the line clear?
    Yes that would work for the pump feed line. You may also want to flush the return line. Maybe do both at the same time with a hose on the disconnected feed line to the disconnected return line. Then disconnect the return line at the tank and pump till the gas runs clean.
    Dave M vin 03572
    http://dm-eng.weebly.com/

  2. #12
    Delorean Guru
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    Before cleaning the lines you should get the tank as clean as you can and after you flush everything, clean the tank again.
    David Teitelbaum

  3. #13
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    Patience is key. One crank attempt that pulls any sludge through the system will cost you significant time and money. Fight the urge that says I think its clean enough to try. You will be very happy you did as you learn more about the car and read the stories of folks who cranked with bad gas and sludge after years of sitting.

  4. #14
    Junior Member AZ-D's Avatar
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    Quote Originally Posted by Bitsyncmaster View Post
    Yes that would work for the pump feed line. You may also want to flush the return line. Maybe do both at the same time with a hose on the disconnected feed line to the disconnected return line. Then disconnect the return line at the tank and pump till the gas runs clean.
    Just to clarify, fuel runs from the line on the bottom of the filter and exits to the engine through the top correct? Also, my thought was to keep the return line out of the tank and just run it into another container to make sure stuff stays out of my clean fresh tank. Is there some kind of diagram on here that shows the directional flow of fuel through the lines? I'm not exactly sure here I would tap into the return line at the same time.

    After I flush the feed line to the fuel filter, can I do the same thing with the line from the filter at the fuel distributor? As in disconnect the line at the distributor and jump the relay to push anything out of that section too.

    Quote Originally Posted by David T View Post
    Before cleaning the lines you should get the tank as clean as you can and after you flush everything, clean the tank again.
    The tank was surprisingly clean, but I pulled everything out and did a full cleaning regardless and replaced the baffle screen and hoses inside. Good call on cleaning after as well.

    Quote Originally Posted by crbritt83 View Post
    Patience is key. One crank attempt that pulls any sludge through the system will cost you significant time and money. Fight the urge that says “I think it’s clean enough to try.” You will be very happy you did as you learn more about the car and read the stories of folks who cranked with bad gas and sludge after years of sitting.
    I am currently fighting that urge of clean enough. Once I peaked inside the end of that line I realized I need to go further. This car has not been sitting for very long so its not as bad as it could be. The car has 98k on it so I am hoping for some good results when it comes to start up time.
    Last edited by AZ-D; 01-10-2020 at 06:37 PM.

  5. #15
    Junior Member AZ-D's Avatar
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    My VIN:    Previous owner of 2646. I have no idea where it is now.

    I removed the original return line hose from the hard line near the pump. It seems like the hard return line is blocked. I can not stick my poker tool into the line like I can with the feed line. It will only go about a half inch inside.

    Can anyone elaborate on this part of the original referenced ::How to::

    ""Now, don't flush the fuel distributor, instead go to back to the engine area and locate the fuel feed and return lines at the distributor and disconnect them. These are large banjo fittings on the ends of the hoses, don't think about trying to disconnect them. Instead put a fender washer and rubber gaskets onto your 1/4" bolt and slide on one bango, the the other, then another rubber washer and fender washer, finally the nut. The fuel will flow, but it also will leak. Set this up so it cannot drip or run down the lines and drip, and get the connection into the second small tub. keep an eye on it during the flushing process, especially the first time you turn on the cheap pump.""

    It's saying to disconnect the feed and return from the distributor, but do not remove the banjo from the line correct? Then, the bolded part is what I don't understand the most. I am supposed to basically bolt the 2 banjo fittings together?

    Does anyone have pictures of what this is supposed to look like? A visual how to of this process on here somewhere maybe?
    Last edited by AZ-D; 01-10-2020 at 09:25 PM.

  6. #16
    Administrator Ron's Avatar
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    $.02

    If you want to fire it up, disconnect the fuel pump and use starting fluid....

    Gummy deposits or a blockage in the lines indicates that you should remove the lines and clean them one at a time -- Anything else is asking for it!
    That said, if you want to blow them out with air, you can get nuts to fit the different size banjo bolts. Put a flat washer on the banjo bolt (to keep from scaring the banjo), then the banjo, another flat washer, and finally the nut. Then blow air into the end of the banjo bolt....

    You asked about the flow: Pump -> Filter -> FD -> then simultaneously: 6 injectors, CSV, WU/CPR, CSV. The WUR/CPR and FV have return lines back into the FD. These two return lines (and the main return) connect to the two rearward, passenger side ports on the FD. The two ports are connected together inside inside the FD. This is why it would be hard to flush the lines following the flow. E.G. If you disconnect the line at the WUR/CPR feed port and push fuel/air through the FD, trash and fuel can also flow backwards through the WUR/CPR return line. That would mean yet another place to catch fuel and contaminating the WUR/CPR...

    FWIW- Unlike carb systems, there is no such thing as being too "involved" when it comes to cleaning K-Jet fuel lines.

  7. #17
    Junior Member AZ-D's Avatar
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    My VIN:    Previous owner of 2646. I have no idea where it is now.

    Quote Originally Posted by Ron View Post
    $.02

    If you want to fire it up, disconnect the fuel pump and use starting fluid....
    Fuel pump is currently disconnected. I have not reinstalled the tank yet. What is the benefit to using starting fluid? And how does that even work?

    Quote Originally Posted by Ron View Post
    Gummy deposits or a blockage in the lines indicates that you should remove the lines and clean them one at a time -- Anything else is asking for it!
    That said, if you want to blow them out with air, you can get nuts to fit the different size banjo bolts. Put a flat washer on the banjo bolt (to keep from scaring the banjo), then the banjo, another flat washer, and finally the nut. Then blow air into the end of the banjo bolt....
    That makes sense. At this point I should probably just buy all new fuel lines cause the original ones are on the car and I will have to buy new ones eventually regardless.

    What is your recommendation for clearing the blocked hard return line headed back to the pump?

  8. #18
    Administrator Ron's Avatar
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    Quote Originally Posted by AZ-D View Post
    Fuel pump is currently disconnected. I have not reinstalled the tank yet. What is the benefit to using starting fluid?
    I only mentioned it because you said, "If it won't fire, no reason to worry about anything else yet."
    People roaming the junk yards looking for an engine use it all the time -- Helps identify if one knocks/smokes/etc.


    Quote Originally Posted by AZ-D View Post
    And how does that even work?
    Check this out:


    FWIW, I wouldn't run it any longer than it takes for it to prove itself (seconds).


    Quote Originally Posted by AZ-D View Post
    What is your recommendation for clearing the blocked hard return line headed back to the pump?
    I'd try Acetone (or Xylene), in both ends, and let it soak overnight. Then get try to blow it out with the air compressor. If that didn't do it, I'd replace it.
    I wouldn't get either near non-metal parts in the fuel system.

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