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E320 poor start

Discussion in 'Electrics, Vacuum, Ignition and ECU' started by richardmorris, Dec 10, 2012.

  1. richardmorris

    richardmorris Senior Member

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    Your Mercedes:
    1994 E320 coupé
    Hello all,

    For the first time in the 6months I've owned it my '94 E320 didn't want to start this morning. It caught the very first time the key was turned and died before it really got going, then took four or five goes to fire when it then ran fine.

    Battery is fine (new) and the starter was going ok too.

    Any ideas? It's started in colder weather before now, this morning was just a little chilly really.

    Thanks,
    Richard
     
  2. kth286

    kth286 Senior Member

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    Your Mercedes:
    E320 Coupe 95
    I use Shell in mine - nil problem.
     
  3. william28ho

    william28ho Active Member

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    hi - the w124 is a simple car to fix.

    as you turn to start the car, just before you crank the car's engine, do you hear a 'whirring' noise (from the back of the car)?
    this is the fuel pump being started, pumping fuel into your engine.

    if you hear no 'whirring' noise', then the fuel pump is not working.

    another point, your car is a 1994 which uses the OVP relay ( located behing the car's battery), this can also give rise to problem....due to age....wear and tear....whereby the old and odd items will stop working....

    it can also be the distributor cap, being old and in need of replacing.


    i hope this has help.
     
  4. OP
    richardmorris

    richardmorris Senior Member

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    1994 E320 coupé
    Thanks for the replies folks. It's got shell V power in at the moment - extra points voucher time.

    One reason for getting the car was I was fed up with my extremely clever citroen C5 HPi - clever but neurotic. So I hope the 124 is easier to fix!

    It was ok on the way home from work - haven't tried it this morning though as I need to collect my bike from the shop and there's a major design flaw in the coupe in that my bike won't fit in the boot. I'll see how it goes tomorrow.
     
  5. robparker

    robparker Senior Member Authorised Forum Supporter

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    Your Mercedes:
    C55 (203), 220d (115), 200d (110)
    OVP as already suggested, or clean the throttle body (not the easiest thing to do on that engine). No dizzy cap on that model.
     
  6. OP
    richardmorris

    richardmorris Senior Member

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    1994 E320 coupé


    Hello again,

    It did it again yesterday in Calais - after about a continuous days driving up from Le Mans. Stopped for about 30mins and although it cranked over fine it wouldn't fire.

    Now since it last did this I have been listening to the fuel pump whirr when the ignition is on. It didn't do this when it wouldn't start. I left it to cool down for a few minutes, got out opened the bonnet etc. Nothing obviously amiss with the fuses, got back in shut the door. Turned the key and heard the pump whirr and it started.

    I seem to remember reading somewhere on here that there are two supplies to the pump, one to start and one to run is that correct? Could the relay to the starting of the pump be iffy?

    Thanks for any advice - it started fine after that, and again ok this morning.

    Richard
     
  7. robparker

    robparker Senior Member Authorised Forum Supporter

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    Your Mercedes:
    C55 (203), 220d (115), 200d (110)
    The fuel pump relay for that model is behind the battery and is a small green relay with a fuse on top. But im not sure if there is anything else aswell that could break preventing the fuel pumps from running.
    I wouldnt think an immobiliser as that would probably not let you crank the engine atall.
     
  8. OP
    richardmorris

    richardmorris Senior Member

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    Thanks - Actually I thought that relay with the fuse was the OVP! Is that somewhere else then?

    It's not the immobiliser - that played up in Feb. so I had it disabled permanently.
     
  9. robparker

    robparker Senior Member Authorised Forum Supporter

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    This green one is a small relay, the OVP is in the same sort of place, but I think on the right hand side, and is silver (but may have a removable black sleeve covering it), taller and also with a fuse on top.
     
  10. OP
    richardmorris

    richardmorris Senior Member

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    Thanks Rob - a couple of things to look for then!

    Richard
     
  11. kth286

    kth286 Senior Member

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    I guess it could be the OVP relay printed circuit board with heat break in it when hot.

    cools down and is OK again.

    The crank sensor is an essential sensor for starting, and they can go faulty when hot,
    but more common fault on later cars, than 124s.

    There is an essential earth point behind instrument cluster which can go rusty.

    The fuel relays are inexpensive if you can get to dealer.
     
  12. OP
    richardmorris

    richardmorris Senior Member

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    Thanks David,
    I've a feeling it's this green relay - managed to find it last night, although I haven't removed it to look at yet, it's not the easiest to fit my hands through the gap. Seems to be about £10 or so.

    The other relay with a 30A fuse on the top was cable tied to a bundle of cables to the back and right of the battery - I expect this isn't original and has been replaced in the past. Green relay was very dusty though.
     
  13. OP
    richardmorris

    richardmorris Senior Member

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    Having taken the green relay out the contacts seemed fine, no sign of corrosion, so I bought a replacement and have just fitted it.

    For completeness I want to make sure the contacts on the fuel pump itself, so could someone point me in the right direction to find it?

    Thanks,
    Richard
     
  14. robparker

    robparker Senior Member Authorised Forum Supporter

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    Your Mercedes:
    C55 (203), 220d (115), 200d (110)
    Under a cover under the car by the drivers side rear wheel
     
  15. OP
    richardmorris

    richardmorris Senior Member

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    Thanks Rob,

    From the noise when turning the key I'd assumed it was in the engine bay!

    Richard
     
  16. kth286

    kth286 Senior Member

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    Your Mercedes:
    E320 Coupe 95
    there was a change to single fuel pumps around your car time, instead of 2 pumps.

    I only have one pump on my Aug 1995 car.

    It is with the filter under the removable cover in front of rear wheel (offside).

    Held on by 4 (I think) small 10mm nuts which are recessed.

    You will need a deep 6 inch tube type 10mm socket OR thin extension with normal socket.

    You can access it just by jacking that rear side up - ensuring you put an axle stand under for safety in case jack moves.

    Ensure footbrake is fully on also.
     
    Last edited: May 21, 2013

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