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Tach on an EFI engine

Discussion in 'Daihatsu Hi jet' started by greg0187, Aug 13, 2008.

  1. barneyrb

    barneyrb Member

    I have to ask, what RPM is the tach reading at 45mph or around 70kph?
  2. greg0187

    greg0187 Moderator Staff Member

    I assume you want the reading when the needle is @70kph. I have 25" tires so my speedo is off, but I don't think it matters, I'm just not actually traveling that speed. Someone correct me if I'm wrong??? I don't drive mine on the street here at my house but next weekend when I take her to the country I will see.

  3. Mighty Milt

    Mighty Milt Moderator

    you are right greg, rpm vs. speedometer is the same relationship regardless of the tire size.
  4. 235bill

    235bill New Member


    I installed a inductive digital tach. from Northern tool it took a little fooling around to get it to work properly but display will go blank if it is in direct sunlight or some other heat source, this makes the hour meter usless as it returns to zero when readout goes blank but all I was interested in was RPM anyway, @100K it reads 3250 RPM.
  5. greg0187

    greg0187 Moderator Staff Member

    Cool. On my EFI engine I couldn't find a way to install an inductive tach. I tried to take some readings this weekend and at one mental note, at ~60kph it was reading ~2400RPM.
  6. Mighty Milt

    Mighty Milt Moderator


    in what gear adn in what range? sounds high if it's in 5th?
  7. greg0187

    greg0187 Moderator Staff Member

    Thats High range 5th gear.
  8. 235bill

    235bill New Member

    Any tach with inductive pickup will work no matter how many cyls because you only register the number of pulses (RPM) on the cylinder the pickup is on. If pickup is on coil lead it will register once for each spark on a three cyl. you will have three pulses for each rev. Just checked RPM @60K -(38mph) it is 2000 rpm
  9. myhijet

    myhijet Member

    With the 3 coil setup the twin cam has, there is no plug wire but the pos and neg wires are accessable on the coil. The coils set directly on top of the plug which goes through the valve cover.
  10. greg0187

    greg0187 Moderator Staff Member

    Just an update to this post...

    I was working with another member with a newer model truck to get his tach working and he found that the tach signal wire (Red w/yellow stripe at the ECU) was actually taped into the harness behind the instument cluster rather than terminating at the connector to the cluster like mine was. Sorry for the confusion.:confused:

  11. Joe Newberry

    Joe Newberry New Member

  12. greg0187

    greg0187 Moderator Staff Member

    Hi Joe, Thanks for posting this. Although a valid statement the author failed to include a very important piece of information. Using this method requires a tachometer that has a 1 (one) cylinder setting. Also, it relies on a common +12v with a switched negative from the ECU. It does not guarantee that all systems operate in this manner. In addition, the pulse width of the signal to the injector varies according to atmospheric conditions (as controlled by the ECU). It is unknown if there would be any ill effect on the tachometer operation due to the variance in pulse width.

  13. Arcticmini

    Arcticmini Member

    Rpm gauge

    Checkout tinytach.com. It looks simple and cost $47
  14. greg0187

    greg0187 Moderator Staff Member

    This wont work on a daihatsu EFI engine. It doens't have any spark plug wires to attach the pickup to.
  15. El Ventu

    El Ventu Member

    I think it is probabily right the tach if you read 1100-1200rpm at idle, if your truck comes directly from Japan and anyone tuned it on US gasoline.
    The three cyl. engine seems to rev slower than it do...
    I feel the difference, and I'm italian, and here we have about only 4 cyl. cars, in US I know that cars has more displacement and cylinders...
    You can adjust the idle (and then, after, the CO emissions).

    You can find the workshop manual @ http://www.daihatsuhijet.co.uk/manuals-downloads/

    I hope this helps.
  16. El Ventu

    El Ventu Member

    I bought a tachometer for mine.
    On its instructions, manufacturer says to connect it at the negative wire of the coil.

    I can't try to connect it at now, but this week I do the work (I'm waiting for the tacho support that I bought on e-bay), then I say what to do.

    Mine is a Piaggio Porter, but it is the same thing of the Hijet.
  17. El Ventu

    El Ventu Member

    Tacho and EGT gauge mounted on the dashboard...this weekend I try to connect it.

  18. El Ventu

    El Ventu Member

    Mounted and connected, it works perfectly.
    I bought a "pilot" brand tachometer for about 50€ on e-bay.
    Simply I set it to 3cyl and connect it to the negative of the coil.

    Seriously I can't understand where it is the problem...
    Thinking on what i read on this forum, I imagine I was in trouble and I figure to have huge problems to make it work...

    I think, or the problem is in the type of tacho you bought, or about no one knows how and what to do to connect it... :p
  19. greg0187

    greg0187 Moderator Staff Member

    Mine was a fuel injected engine with coil on plug, distributor-less ignition. that's probably why yours was easier.
  20. El Ventu

    El Ventu Member

    In yours you need a tacho for a single cylinder engine, than you connect the negative of the coil to the tacho...I think it is easier than mine...

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