1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Starting and running issues - '97 Hijet (EF-NS)

Discussion in 'Daihatsu Hi jet' started by bfrscreamer, Apr 29, 2023.

  1. bfrscreamer

    bfrscreamer New Member

    Hello everyone. Been lurking for many years, but first time posting.

    I'm having starting and running issues with my 97 Daihatsu Hijet (EF-NS). Over the winter, it developed issues starting when cold. I would have to repeatedly crank the engine and flutter the gas, but it would always start well if plugged in. The choke appeared to be getting stuck, so I cleaned it and lubricated it, and added Seafoam to the fuel.

    The choke no longer sticks, but the truck now has difficulties starting and running properly. I now have to manually hold the choke open and pull the throttle for a minute or so at cold startup to make sure it idles (starts fine again once warm, but still runs worse than usual). I've also had to back the cold idle screw off entirely to make sure the accelerator doesn't "hang" when revving and shifting, meaning I have to feather the accelerator on startup. The engine mostly revs up correctly, but often snorts if I give it a quick punch on the accelerator. There seems to be a slight loss of power and the idle isn't quite as smooth as it used to be. The catalytic sensor blinks on and off when warming up if I press on the accelerator, but eventually stops (Not entirely sure what this is telling me, but I feel it is still related to the carb).

    I've watched Fupa's guide on adjusting the carb, but making the appropriate adjustments (really, any adjustments) doesn't seem to fix the problem. I had set the idle speed between 1200 and 1500, but after a short test drive, the truck will get stuck idling at 2000 when warm. Currently, it is warm idling around 1000 and not getting stuck at higher rpms, but I think this might have to do with essentially having no cold idle (??). I've been thinking about replacing all of the vacuum lines, but wanted to get some advice before I start tearing into that.

    Any help would be greatly appreciated. I'm sure I did something wrong somewhere, but I can't figure it out and I'm starting to lose my mind!
     
  2. HiJinks

    HiJinks Member

    I can’t really speak to the idle/run issue, but my ‘93 Hijet has experienced the cold/damp starting issue.
    I had recent success with replacing my starter. Last year my son burned my clutch up. I replaced it. The clutch material I found was crazy. Looked like a bird nest.
    When I replaced the starter, I had to swap out the snout with the old starter to fit my truck.
    I believe the old starter pulled in some clutch material and this was affecting performance. The dusty dirty condition may have as well.
    In short my cranking power is like new.
    To remove and clean the inside of the starter is a fairly easy task.
     
  3. Jigs-n-fixtures

    Jigs-n-fixtures Well-Known Member

    First go into your profile, and put some info on your truck in the signature. It makes it lots easier to lend a hand when you need a hand.

    Sounds like you have too high of fuel pressure, and it is letting fuel get past the needle valve. Which makes your mixture too rich to run. And Fupa’s video was on a s80, and the carb is different on your S100 series truck. The S80 had two screws, and the S100 has three.

    First thing to do is get a vacuum/fuel pressure tune up gauge. They don’t cost much, and are highly useful when your working on these older rigs. Check the fuel pressure at the carb inlet. If it higher than bout 2.25-psi, get a pressure regulator and get it down. To close to 2-psi.
     
  4. Andy King

    Andy King New Member

    Last edited: May 9, 2023
  5. Jigs-n-fixtures

    Jigs-n-fixtures Well-Known Member

    That is right. I think, not sure on the idle and the load kick up screw. Post a side view and I will know for sure.
     
    Andy King likes this.
  6. Andy King

    Andy King New Member

    The eureka moment for me was figuring out the venturi adjustment knob.
     
  7. Jigs-n-fixtures

    Jigs-n-fixtures Well-Known Member

    Ok, the “Venturi Adjustment”, is the idle mixture adjustment. You may have to pop the Plastic off of it to get a full range of adjustment. I have posted several times on how to set the best lean idle. You will need a Tune-up tachometer. Basically with the truck warmed up, set the idle as low as it will go. I got mine down to about 600-rpm. What you are doing is making sure all the fuel comes from the idle circuit, and none of the enrichment circuits are coming in to play.

    Then you turn the mixture screw in a quarter turn. If the idle speed drops off, you leaned it out and you need to turn it the other way. You keep turning the idle mixture screw until you find the sweet spot where it idles teh best with the leanest mixture.

    I think 2 is the hot idle adjustment, and 3 is the kick up for AC or high alternator demand, etc, depending on your options. On mine the kick up comes on when the A/C is on or if I am lifting the bed.

    Under load the speed, and manifold vacuum drop, which relaxes the diaphragm, which opens the throttle a bit and regains the rpm.
     
  8. Andy King

    Andy King New Member

    On my EF-NS the kick up comes when the a/c system sends an electric signal to a vsv removing vacuum from a vacuum pot allowing the throttle up.
    My troubles with this pot Not releasing its vacuum is driving me crazy as it used to work. I do not know how/ where the pot bleeds off the vacuum. I'm thinking of taking it off and boiling it. Lol
     
  9. Jigs-n-fixtures

    Jigs-n-fixtures Well-Known Member

    I think the vacuum valve is supposed to release the vacuum when it closes the feed.
     
  10. Andy King

    Andy King New Member

    Hmm... that makes more sense.
    There are three hoses to the vsv. They are the vacuum supply, the hose to pot, and one goes to the air box.
    I think I'll try applying vacuum to the air box hose to see if I can draw the vacuum out.
     

Share This Page