Hall sender

Discussion in 'Mk2' started by Joehough, Apr 19, 2019.

  1. Joehough

    Joehough Paid Member Paid Member

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    Some of my wiring is old and decrepit and I noticed a brown and white one going to a lug on distributor was quite bad and nearly broken off the terminal. So I scotch locked a new piece of wire onto it and crimped on a new connecter. From my haynes manual I deducted it was from ignition ecu to hall sender. I also managed to break the plastic fitting on the distributor housing that has a few wires that go into on a block connector. Then I went for a spin and it is missing, also rev counter jumping about all the place and idle fluctuating. Am I right to assume hall sender wiring now ruined and new dizzy required?
     
  2. rubjonny

    rubjonny Administrator Staff Member Admin

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    having a loose hall sensor plug isnt ideal, but assuming the wires and pins inside are not damaged then it should still work alright. my mk1 16v had the plug housing cable tied on the side for as long as I owned it and no issues :lol:

    the hall sensor can be changed but finding a genuine bosch part for decent money can be tricky, worth looking up local bosch specialists and see what they can do for you
     
  3. Joehough

    Joehough Paid Member Paid Member

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    Cheers Jonny, I bought a new (made in China) dizzy and just fitted it. I used an old school Gunson timing light on the big timing mark, but couldn't find a red wire to the coil, only red and black so didn't take any wires off, will that make a difference? The dizzy is in a different position to old one to get the timing right, so assume it was out. Throttle response seems to be better, but idle is up to 1200 with the screw right in. The o ring is broken so I guess replacing it will make a difference.
     
  4. rubjonny

    rubjonny Administrator Staff Member Admin

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    its the red/black wire spade plug near the dizzy you unplug when doing the base settings, this is so the ISV module doesnt try and compensate for any changes you're making.

    you can add a little more base advance on these usually no problem as logn as using good fuel, about 8 degrees is a good starting point. but the trigger wheels inside pattern 16v distributors can sometimes be manufactured incorrectly which affects the ignition timing, sometimes reducing power. see how you get on with it though.

    high idle can be down to an air leak or bad idle switch, might possibly be isv fault as well. check it all over as per my 16v thread and see how you go anyway, get the idle screw o'ring replaced for starters. If you have put new injectors in without the top hats on then you'll need to blocvk the vacuum hose to the inlet or 5th injector housing from the breather hose as you'll have an air leak there too
     
  5. Joehough

    Joehough Paid Member Paid Member

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    Thanks Jonny, I have got the same if not a bit more poke than before but still topping out at the the ton. Don't think I am getting full power, but I suppose there are loads of things it could be. I am not savvy enough to sort it myself so will get it booked in with stealth.
     
  6. Joehough

    Joehough Paid Member Paid Member

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    Is Jonny around? I have been fiddling with fuel mixture, and did have a lumpy idle and a bit off a stutter and misfire when it hit about 4k rpm. I thought the mixture may be too weak, so turned the screw an eighth of a turn at a time, after 2/8 the misfire seems too have gone. Would this be a symptom of weak mixture?
     
  7. rubjonny

    rubjonny Administrator Staff Member Admin

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    have you checked thru everything in my guide yet?
    https://clubgti.com/forums/index.ph...air-and-tune-your-mk2-corrado-1-8-16v.195423/

    ideally you want it on proper CO testing equipment, I've found the DIY stuff a bit hit n miss. Aim for around 1.5-2%, maybe a little more whatever it runs happy at. You have a lot of headroom in the old MOT rules :lol:

    if you think it might be a bit lean first make doubly sure there are no air leaks, if its had new injectors without the top hats you'll want to cap off the nipple for the air shrouding system on the breather hose as you'll have an air leak there. Plus if the plastic inserts and seals havent been replaced maybe they're leakign or cracked, its easy to do when fitting the inlet as they poke out into the head
     

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