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[SOLVED] 85 hijet gas in throttle body

Discussion in 'Daihatsu Hi jet' started by 85hijettison, Jul 30, 2021.

  1. 85hijettison

    85hijettison New Member

    Truck is running real poor. Seems the throttle body is filling with gas and possibly gas in the oil. It wants to die especially when warm and can stall out with the clutch in. On wot with accelerate then start chugging and wanting to die.

    I am leaning towards the fuel pump. It does not want to restart once it starts chugging at WoT even when it will idle okay. It has to sit for a bit to start easy.

    Also once it starts chugging it does not go away if you back off the throttle and speed until it slows down significantly. It wants to die even if you take your foot off.

    It has the external manual fuel pump.

    So far checked the fuel filter and charcoal canister.

    The filter was able to drain from the tank fairly easily and running with the charcoal canister unhooked does not seem to make a difference.

    Any ideas?
     
    Last edited: Jul 30, 2021
  2. Limestone

    Limestone Well-Known Member

    85,
    This typically sounds like several of the past posters problems, getting too much fuel in the Carb.
    There are several past post that you can find using the search button, that will help!

    1 Carb. could need a rebuild
    2 Pump like you mentioned, but if it's working, maybe, not venting back to the tank, like it should,(venting), giving too much fuel!
    3 accelerator, pump,(in carb), part of re build.
    4 Dirty carb., (jets), not allowing proper fuel flow!
    5 Float issues!

    So these are some of the Highlighted points that you'll find in past posts!

    This being your first post, thanks for Filling out your Signature, telling what you have!
    We don't know the true history of the vehicle, as you might not know much about it either, prob. being 2nd or 3rd owner, etc.....
    So not knowing what was done previous, maintenance, mileage, etc......
    Were kinda throwing Darts at a board here, but were still willing to help you, just understand,
    we don't have a magic wand, and were not there!
    Good Luck,
    Limestone
     
    Last edited: Dec 21, 2022
  3. 85hijettison

    85hijettison New Member

    This is where I was leaning. Supposedly it had the top end rebuild 3 years ago that's why I was leaning toward the fuel pump first then carb second. 3 years of grime versus probably never been changed fuel pump.

    If the pump doesn't fix it first I'll probably rebuild the carb and start from scratch.

    It does not seem seem to be air related because once it starts chugging and hard to start holding the choke in any position does not make it easier or harder to get it started only giving gas seems to affect it.

    I'll check the return lines from the pump ad I only looked at the filtered incoming lines so far.

    On the Daihatsu external pump does the small nipple/barb on the bottom side of th three fuel lines need to be open to vent? The bottom one in this image not covered by the red caps.

    [​IMG]

    Mine seemed pretty dirty caked in the usual engine dirt/grime.

    Update: it would not start today so I pulled the plugs and they are fouled. Seems it is running really rich. I am going to try to seafoam in the top end route along with cleaning the plugs and seeing if it helps with the carb.

    I have some suspicion on the choke not coming off correctly along with extra fuel flooding the throttle body.

    Is the choke plate supposed to come fully off to 90 degrees with just the wax melting?

    I noticed there seems to be no way for the throttle linkage to pull it more than 25 or 35 degrees even under wide open.

    Also I pulled the fuel line off the intake and clamped it. Any danger running the external fuel pump with just inlet and return on? I want to shoot seafoam into the fuel inlet on the intake.
     
    Last edited: Jul 31, 2021
  4. Jigs-n-fixtures

    Jigs-n-fixtures Well-Known Member

    If the charcoal canister clogs, the fuel tank builds pressure higher than the two psi of the fuel pump return line and the return line doesn’t send fuel back to the tank, flooding the carb. the pressure regulation at the pump is just.spring loaded valve, which sends fuel back to the tank, when the pressure in the pump goes over about two psi. If the tank has a higher pressure the fuel pump return/pressure regulation can’t work right, and it pushes past the needle. These arbs are essentially motorcycle carbs, with emissions added. And, like the carbs on. Bikes, they want two to two and a half pounds of pressure to the needle. More than that and they flood.

    When it does it, take off the fuel cap. It should suck air in. If it vents air out, the canister is plugged and you will have to bypass or rebuild it.
     
    Last edited: Aug 4, 2021
    Limestone likes this.
  5. 85hijettison

    85hijettison New Member

    I think I have narrowed it to the following:
    1. Valve clearances are possibly wrong 2. Charcoal canister issue 3. Float / carb issue (gummy) 4. Vacuum line leak somewhere 5. A combination of the above with the choke not coming off 6. Plug/ wire possibly weak.
     
  6. 85hijettison

    85hijettison New Member

    Update: I rebuilt the carb and changed the plugs.

    It still won't idle correctly. It settles then idles fast then settles and goes all over the place. It also seems like it won't come off fast idle as the larger screw does not seem to make a difference.

    I checked for pressure with the gas cap off did not make a difference. I think it has proper slight negative pressure as it should. Probably eliminating the charcoal canister.

    I am leaning toward vacuum leak now. I have 10 ft of lines I am going to start replacing as much as I can.

    Any other possibilities? If the timing is way off will it make the idle rough?

    Also the choke still seems to not be working correctly even though I know it's clear and getting heat. I also lubricated the spring and "y" by the throttle cable. I am assuming the metal "y" will go to horizontal when it comes off?
     
  7. bohale87

    bohale87 New Member

    Did you fix your issue?
     
  8. ERINSON DURAN

    ERINSON DURAN Member

    I have a Kia Towner which is the same as Daihatsu Hijet from 1994 to 2000. Many parts are interchangeable between the two between the years mentioned above. I was having a lot of difficulties getting the truck to idle right coming to a stop, I got a new carburetor from EBay and the problem didn't go away. A few days later I figured out that the idle solenoid that goes on top of the carburetor was bad (I swapped it from the old carb to the new one because the one from EBay came without it) I started looking for one but it cost more $ than the new carburetor . Later I found one that looked very similar at an old Toyota's online store and got one for $14.95 . Put it to the truck and problem solved, Thanks GOD because it was driving me crazy. Oh I ordered a second one for my old carburetor since that was the problem of it. Here is the link https://cruisercorps.com/products/throttle-idle-solenoid
     
    JMM, fmartin_gila and Limestone like this.
  9. 85hijettison

    85hijettison New Member

    Fixed this issue. Rebuilt the carburetor then Discovered the teeth on the starter were being eaten so replaced the starter. Also changed the battery cables to the starter and the negative. Changed an reset the idle now it starts and runs well but won't go into 4wd.
     
  10. ERINSON DURAN

    ERINSON DURAN Member

    Hello, your carburetor still working? Having same problem and can't get it working.
     

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