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[solved] LH-2.4 240 cranks, has spark, no injection


Picked up this silver 240 on the weekend and does not want to run, am unsure on any service history or what previous owner might have done to it as the Vin number says it should have a M47 in it but has a M46 it seems to have spark and have even swapped Bosch ignition module out of the gold one but does not help. Fuel pump is running and has fuel at fuel rail, but removed injectors and does not seem to spray fuel when cranked. Have removed the timing belt covers and the timing belt is correct. I wanted to use the motor out of this one in my wagon so was wanting to at least get it running to make sure it is good, the motor cranks well and has good compression. Was thinking possibly crank position sensor but just worried if they have swapped gearbox and flywheel it might not have correct pickups on flywheel. Any thoughts and help, ideas would be most appreciated, thanks in advance


  • jamesincJames @jamesinc Oz Volvo Ice Fortress
    - What year
    - What engine management system

    It sounds like you're running Bosch LH-Jetronic 2.4. Assuming you are, if you have spark, but don't have injection, this would rule out the CPS as the culprit, as a faulty CPS would mean no spark and no injection. The next point of failure would be the fuel ECU. You said you replaced the ignition module, but you probably need to replace the main ECU.
  • k5E0A4Ph.jpg

    Yes this is the ignition module I swapped out with the good one in my gold 240, was thinking as you said main ECU but was unsure where is the main fuel ECU is hiding on these and is it fairly easy to recognise
  • Sorry is a 1989 and think it is the 2.4 system
  • Update so far,

    Have found ECU's and have slightly different part number not sure if that would make any differance, have tried and still no go. While I was removing the ECU noticed that they have cut wiring to the fuel pump relay and put in a different one and left plug for fuel pump relay empty. This could possibly be the problem would this stop car from running even though fuel pump is working? The next thing is once I fix wiring should it have a green or white relay in this year model
  • jamesincJames @jamesinc Oz Volvo Ice Fortress
    edited March 2017
    It is probably(?) LH-2.4 then by the looks of it. White fuel pump relay. But your problem is spark so we should stay focused on that for now.

    What you referred to as the ignition module is what I'd call the power stage.

    The two EZK units you have there are compatible with one another so that shouldn't be an issue.

    It still sounds like an ECU issue. The next thing to check is with the ignition on, you should get a constant +12V on each injector plug (I forget which prong, but... one of them).

    If you want to revert the fuel relay wiring to stock, that is good, but you could rule out the relay as a problem for now by bypassing it. Presumably it worked at some point, so unless a crimp has failed or the relay itself has packed it in, it's probably fine.

    Edit: just to clarify, your car should have TWO computers. The one you have found is the ignition computer. There is a second, separate computer that controls fuel supply. It is located behind the plastic trim cover to the right of the driver's right foot. Take a photo of that computer's part number and we can confirm if it's LH-2.2 or LH-2.4.
  • My question is why the fuel pump is working when you have no spark as you need a coil pulse signal going to the fuel pump relay to operate the relay. So is this why the relay has been changed due to no pulse signal going to the relay.
    So start from scratch and see if you have a pulsed signal going to fuel pump relay if not check it at coil.
  • Looks like a bush mechanic has effed with the wiring
    Your better off fixing the wiring that has been messed with and return it to stock
  • 05FShqOh.jpg

    This is the other ECU, how do you tell the differance is it the part number
  • jamesincJames @jamesinc Oz Volvo Ice Fortress
    561 is an LH-2.4 ECU 👍
  • jamesincJames @jamesinc Oz Volvo Ice Fortress
    If you don't have a spare ECU handy, go and probe the spark system as detailed above. If you do have a spare ECU handy, chuck it in and see if it works.

    And just to clarify, you've 100% confirmed spark is present? You've pulled a plug and seen it sparking as the engine turns over?
  • Yes, have spark as engine turns over had tried both the plug and coil. Will try ECU out of other car
  • What does the insulation on the CPS (crank posistion sensor) at the back of the engine look like?
  • Thought I would check 12 volt at the injectors first, yes it has that and at coil so will try the ECU now will pull out of spare car now
  • Well we have success!!!!!!!!!

    Pulled this one out of the other car and fired up first go and idled great no noises and sounds nice and quiet, was a bit worried about crank position Sensor as the wire looked very perished, makes life so much better when you have a win. Wanted to use this motor in my wagon as it has a slight knock, so can carry on now with that plan now.

    Thanks to everyone who has helped with all your advice

    Just one more thing while researching all this and not being able to use any parts off the wagon as it uses the system in the photo below


    Is this system any better or worse than the LH-2.4 or is it just different
  • edited March 2017
    Well guess you got that one right (@Phillia_Bear) thanks for your help, also thanks (@jamesinc)
  • The ecu loses it's earth and you can probe a wire to earth and see if fires up, but it's been that long since I have done this to tell you which wire it is.
  • Thanks, the ECU is jut out of a parts car so not really worried that it does not work, would have been nice as a spare but just needed to know that the engine ran with no noises as it is being installed it in a wagon I have. But will keep it and do a bit of research and see if can fix.
  • jamesincJames @jamesinc Oz Volvo Ice Fortress
    @Justian I'm just gonna take credit back, the first message in this entire thread is me telling you its the ECU that's faulty 👌
  • Yes got to give credit where credit is due, thanks again
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