1997 Ducato 1.9 TD idle speed & temp question

Discussion in 'Fiat' started by timdownieuk, May 1, 2013.

  1. timdownieuk

    timdownieuk Funster

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    Our new to us van always seems to be idling a bit fast. We also noticed that the engine temp also seemed to rarely get much over 70-75c.

    We've had the stat changed and I had hoped that this would a) bring the engine temp up to "normal" working temp and b) consequently bring the idle speed down from what I assumed was a "cold idle" setting.

    Well, the engine temp has improved a bit (tends to waver around 80 now) but it still fluctuates which seems a bit odd to me, my cars with gauges have always got up to 90 and then just sat there. Is this normal for this engine?

    The idle speed is still high though and I wonder if there's a simple adjustment for this or if it might be related to a disconnected cold idle temperature sensor that the garage found. They assured me though that this was just for raising the idle speed when cold, not lowering it when warm.

    Tim
     
  2. tofo

    tofo Funster

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    my previous engine 1.9 td run hot fans always kickin in
    and the cold start speed came in till it got warm
    then slowed down

    had the cam belt changed and 200 miles later the engine
    self destructed never quite worked out why

    new engine the cold run was disconected /turned off
    and now it idles at the same speed hot or cold

    it also runs colder , i dont check the temperature
    so much know and prefer it that way to be honest

    the fans kick in if it idles in traffic for a longish time
    so they work , there was quite a lot of
    overheating problems for the previous owner
    paperwork came with the van

    id sooner a cold runner than a hot one

    :thumb::thumb::thumb:
     
  3. rainbow chasers

    rainbow chasers Read Only Funster

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    Temperature; Don't panic unduly, but keep an eye on the temp. Running cool is fine, a fluctuating needle is fine so long as it doesn't overheat. Usually it is a sign of either a failing, or sensitive sensor. Whilst it is not getting hot, no action is required. I have had motor homes with fluctuating temp gauges that have functioned without issue for 30k and still doing so. Keep an eye on it - get a spare to have to hand in case, but not to worry! Cool is good!

    Cold Start; The temp sensor is a thermo switch. When you first start it will either remain open or closed (on or off in layman's) until the core inside the switch heats up, expands and makes contact - which will close the circuit - turning it either on or off.

    I know that sounds confusing, but depends in which way it is wired. I was going to describe what happens- but it might get confusing without pictures!

    If your switch is disconnected, then the switch itself will never complete the circuit when the vehicle warms up - so it thinks the engine is always cold. If this circuit never connects, then the relay will never turn on the warm sensor, which will lower the fuel/air mixture and revs.

    So in effect, you are always running in 'cold start' mode - which means the engine is getting more fuel and air and resulting higher idle speed. Like running an older car with the choke open all the time!
     
    Last edited: May 1, 2013
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  4. timdownieuk

    timdownieuk Funster

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    Thanks, that sort of makes sense. All I need to do now is find out where it is!
     
  5. timdownieuk

    timdownieuk Funster

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    Ah, it looks like it's a mechanical idle control system. There's a Bowden cable running from the thermostat area to the injector pump and the end of the cable isn't connected to the pump.

    The cable has a knob on the end held on with a grub screw but I can't for the life of me work out how to join the bits up without a lot of disassembly. You can just make out the cable here.

    http://i1052.photobucket.com/albums...62ad52466b9f15e53baab6c111aac_zps83b19f6a.jpg

    Tim
     
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