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91 S83P - Gas tank pressure, flooding carb, but NO charcoal canister (tentative success)

Discussion in 'Daihatsu Hi jet' started by JMM, Oct 15, 2022.

  1. JMM

    JMM Member

    I know there are a few threads here about the fuel return overwhelming the needle valve and flooding the carb, with the culprit being a clogged charcoal canister. But I'm starting a new one because my truck doesn't seem to have one!

    I've been fighting flooding and rich running for a long time but I seemed to get it under control. But now my problems are back with a vengeance--the top end is totally flooded out, wet plugs, hard starting, so I'd better chase this problem down.

    I've been in, over, and under every inch of this truck (repairs, mods, service items, you name it) and I've never seen anything that remotely resembles a charcoal canister. (FWIW, I've also replaced and/or tested ever vac line, rebuilt the carb/adjusted it endlessly, adjusted valves and timing. New cap, rotor, plugs, etc.)

    My questions for the brain trust and other mechanics better than me:

    1) Are there any cases/years/models where Daihatsu tucked the charcoal canister away in a frame rail, or some other super-secret James Bond hiding place?

    2) Assuming at some point someone ditched it, given my hissing gas cap and flooding would it make sense for me to get and install a canister? (BTW, I've seen references to both vented and unvented gas caps--my gas cap is not vented, and does appear original.)

    3) I know some of you with this problem have bypassed a the canister and rerouted lines. But without that plumbing in my truck in the first place I'm kinda lost--I have no reference points, and no idea if my truck's return lines are improperly routed. And as you all know, there are a lot of Japanese noodles under the bed.

    I wish there was a canister, because at lease I could repair/replace it and eliminate that possibility. But I'm stumped.

    Any and all help appreciated!
     
    Erick Holland likes this.
  2. Tripthyme

    Tripthyme Active Member Supporting Member

    I know of 2 on my s83p on by the fuel tank where the lines come out and 1 infront of the air box. Have you checked to see if your choke is stuck?
     
  3. JMM

    JMM Member

    Thanks @Tripthyme. No canisters by my tank or airbox. Choke is a little sluggish, but not sticking.
     
  4. Jigs-n-fixtures

    Jigs-n-fixtures Well-Known Member

    First pull the fuel cap and listen to determine if the tank is pressurized. If it isn’t pressurized, Trace the return line from the fuel pump back to the tank, and look for blockages.

    Just noticed you have a dump bed. Raise it, and you should have a direct view of the top of the tank. There should be three lines, one is the suction line to the pump, one is the return/pressure regulator relief line from the fuel pump, and one should be the vent line which routes to the charcoal canister.

    Raise the bed, pull the engine access plate, take off the fuel cap, and disconnect the fuel return line at the tank. With the cap off have someone crank the truck and see if it is returning fuel back to the tank.

    If it isn’t getting back to the tank, check to see if it is leaving the fuel pump.

    Or, just abandon the return line and install a small, 3 to 5-psi electric pump back at the tank, and a pressure regulator just before the carb, set to 2.5-psi.
     
  5. Tripthyme

    Tripthyme Active Member Supporting Member

    Cat clogged? What did you do the first time it did this to you? Can you test fuel pressure? The canisters don't look like one on a car. They are a cylinder with 2 orifices on top one on bottom. Just incase you didn't know. Did you replace vac lines 1 by 1 so you didn't miss rout one?
     
  6. JMM

    JMM Member

    A bottle of whatever you drink to @Tripthyme! I woke up this AM thinking about your choke question--and when I dug in, it was screwed up after all. The choke spring grabs a little tab on the butterly actuator--it had slipped off. I took it aparrt, cleaned it, set the teeth on the right gears, and she's running pretty well, cold and warm.

    Some road testing and letting her sit overnight will let me know if I'm still running rich/flooding, but no question the choke was a problem. Of course, I still don't have a charcoal canister (nor a cat) :)

    thank you for pointing me back to basics, fren.
     
  7. Tripthyme

    Tripthyme Active Member Supporting Member

    Great news. I have been fighting with mine for a week or so. Coolant lines running to the carb bone dry with rust lime scale. Flushed flushed flush replaced lines to carb. Air locked in system can't get it out. Then I created my masterpiece! I took 2 a/c fill ports and spliced them into the middle of those 2 lines. They are the highest point of the cooling system. So now I can bleed them easily and always know I have coolant up to there.
     
    Jigs-n-fixtures and JMM like this.
  8. JMM

    JMM Member

    I spoke too soon and probably angered the Hijet gods. Even with the choke working properly, after sitting overnight it's now running like crap again--exhaust stinks of raw fuel. I didn't even bother pulling the plugs, I'm sure they're black.

    First order of business: I'm going with the Motocheez solution and getting rid of this awful, ancient carb that I've been wrestling with for 3 years (). Will probably also add a fuel pressure regulator. Fuel pump is original, so may have to look at that too. Still doesn't answer the canister question!

    (BTW, how many things do I have to replace before this is considered a new engine?)
     
  9. t_g_farrell

    t_g_farrell Active Member

    These are 25+ year old vehicles. Can't say I'm surprised. I've left my van carby alone even tho its a little hard to start (suspect choke is not fully functional) but still runs great once warmed up. With all the vac lines and the age of these carbs, a carb rebuild may help or it may cause even more chaos as other systems react to a properly tuned carb.
     
    JMM likes this.
  10. JMM

    JMM Member

    Installed the $89 aftermarket mechanical-choke carb made of Chineseum. It started on the first crank, but then would fall on its face with any gas. I went through EVERYTHING. Timing, vac hoses, carb jets & float, fuel/filter, checked timing belt to make sure it hadn't skipped a tooth, etc. etc.

    It turned out that the accelerator pump on the carb was way over-juiced. I backed it way off and now have acceptable throttle. It's always the simple stuff.

    Now that she's running, I'll be better able to see if I've still got a fuel/tank pressure issue. Thanks for the help & moral support.

    I can't say I'll miss that old carb or the vac hoses I was able to eliminate. The motocheez video was invaluable.
     
  11. ElevenCharlie

    ElevenCharlie New Member

     
  12. ElevenCharlie

    ElevenCharlie New Member

    Same issue here, same truck, same overnight run like crap again, these instructions cleared that up. C1.JPG C2.JPG C3.JPG C1.JPG
     
    shogun likes this.
  13. JMM

    JMM Member

    Yes, I have a well worn/dirty copy of this in the garage--great doc.
     
  14. JMM

    JMM Member

    Just providing a little update for those considering a manual choke carb: I'm happier by the day. It does take some tinkering/adjusting (and I'm the farthest thing from a carburetor pro) but I have the truck running pretty well right now. Tomorrow, I check the plugs for color.
     

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