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W124 230TE Starting Problem (1991model)

Discussion in 'Engine, Drivetrain, Fuel and Exhaust' started by Rob Linus, Jan 17, 2015.

  1. Rob Linus

    Rob Linus New Member

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    Your Mercedes:
    230TE (1991) (W124)
    Hi folks. After a long drive I stopped my w124 230te '91 outside my house and let the engine run on idle. Suddenly the engine stopped and I cant get it started again.

    I have searched forums for what it could be and the fuel relay + fuel pumps was suggested to check out first.
    An easy way to check the relay and pumps together was suggested:

    -Remove the fuel return hose from the injection unit and mount a small piece
    of hose to where the return hose was sitting.
    -Put the new hose into a 2 liter container and turn the ignition on.

    If the relay is ok the pumps will start up, and if the pumps are ok, they will pump about 1 liter in 40 seconds.

    I watched a couple of videos on youtube where this was done and the pumps keep going with only ignition on. (not engine started)

    -When I turn on the ignition I hear a relay click and the pumps start running.
    but after 1 or 2 seconds the fuel pumps stops. I can hear something making a clicking noise first, and then the fuel relay clicks of and the pumps stop.

    If I floor the gas pedal and turn key all the way, the engine manages to start for a second before stopping. something shuts off the relay.??

    It seems like the relay and pumps are ok, I get a lot of fuel in the container for that short time running.

    I would really appreciate getting some ideas on what this could be !!!
    Thanks!
     
  2. mattkh

    mattkh Senior Member

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    Your Mercedes:
    W168 1999 1.6
    Hi
    Are you getting a spark ?
     
  3. stwat

    stwat Senior Member

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    The fuel pump only runs for a second at first to prime the fuel system. When the engine is started it will then run constantly. To get it to run constantly with ignition on only, you need to bridge pins 87 and 30 on the relay. If the car then runs you know its a duff relay.

    The OVP (over voltage protection) relay can also fail. The solder joints can crack after all the years of heat cycles, hot cold, hot cold etc. You can remove the cover and check for dry cracked joints and resolder. But new ones aren't that expensive.
     
    Last edited: Jan 17, 2015
  4. OP
    Rob Linus

    Rob Linus New Member

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    Your Mercedes:
    230TE (1991) (W124)
    Thanks! Are the fuel relay the small square one all to the right (with a 10a fuse in the top) and the OVP the wider and larger black one?

    The small square one has been checked for cracked soldering and tested manually. The switch inside that one is good.

    I also got a tip that there is a sensor mounted somewhere in front of the engine that sends signal if the engine is turning, and if its broken it would keep the pumps from starting too.
     
  5. star

    star Forum Supporter Authorised Forum Supporter

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    The other way round, the Ivo has the fuse. Also check under inlet manifold for a 25mm black pipe that falls off.
     
  6. mattkh

    mattkh Senior Member

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    Hi
    If the engine stopped suddenly, then I would suspect an electrical fault other than the fuel pump not sending fuel.
     
  7. star

    star Forum Supporter Authorised Forum Supporter

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    That's ovp has the fuse. :)
     
  8. OP
    Rob Linus

    Rob Linus New Member

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    Your Mercedes:
    230TE (1991) (W124)
    Thanks allot guys, knowing what the relays are, and what they are supposed to do
    got me going into this problem with new energy..hehe
    I have studied the fuel system from the brilliant technical manuals I found
    on w124-zone (dot com) and some pictures I found here and there.
    ..And I think I am starting to understand how its really working.

    So..Please correct me if anything I write below is incorrect:

    (The connections I refer to is shown on the picture below)

    The relay's internal controller circuit gets its +V feed through the OVP controller relay when
    the ignition is turned on. (top left connection)
    When the engine begins to turn the EZL-ignition control unit sends a +V signal to the
    pump relays RPM signal input connection. (bottom left conn.)
    There is a camshaft position sensor connected to the EZL that detects if engine is turning..

    When both connections on pump relay are hot, the relay will keep the
    fuel pump switch closed, and the pumps will be kept running.
    If the rpm signal is being cut off for more than 1 second, the fuel pump switch opens up and the pumps stop.
    The pump relay then controls the cold start valve. (bottom connection on the right side of the RPM input connection)

    -Is that the one Star is talking about?
    So if the rpm signal is missing, the EZL or its sensors is maybe not OK,? and if there are rpm signal, I guess the pump relay with its delicate circuit and a zillion soldering points very lightly is to be bad,,?

    [​IMG]

    The pictures of the whole fuel system thats attached shows a 6 syl. engine, not a 4 syl. like in the 230. Is it correct to assume that most of the control systems are alike on both engines? I got the impression that they are..?
     

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  9. star

    star Forum Supporter Authorised Forum Supporter

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    The 25 mm pipe is under the manifold directly under metering head. It's easier to bridge relay as previously surgested. Personally we open relay and inspect relay to board connection, then close contacts with a bit of card to run pumps continuously to eliminate other stuff.
     
  10. OP
    Rob Linus

    Rob Linus New Member

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    Ok, the pump and relay has been tried today and I have a conclusion

    I have re-soldered every single point on the fuel pump relay and double checked the ovp.
    I placed them back into the car and had a go..

    First thing I can say for sure is that the fuel pumps are running like they should!

    -Its 100% sure that they run when engine crank shaft starts moving, and
    when i turn off the starter motor I hear the pumps run for a extra second
    after the engine is all stopped.

    My conclusion is that the fuel pump relay and the ovp is not the problem.

    So, what happens when I turn the engine? This sound:

    -rah rah rah tha tha thaThaTHA THaTaTHa rah rah THATHA TA THA Tha thA rah rah tha Tha ThATATTATHA t rah rah rah....

    Lol I couød not resist to do that, It sounds exacrley like that to me. haha

    Well if explained in a serously way with words:

    Its a few sterter motor turns with no cylinders firing and then it fires and its almost starting
    properly.. but dies totally. and repates sane vegbehacior again. this goes on until the battery is drained-

    I really hope that someone have some idea of what to check next!
    This car has been through to much now to be left for dead!

    I used allot of time in 2014 to win the chemical war on the rust both imside and outside.
    having rear windows removed , killing rust, then fitted again.in a non leaking back end now.
    The sun roof top has now a text written on its underside.

    "if the roof is tilted up when you read this, you are doing it wrong!!
    And for Gods sake dont loosen those 2 bolts on each side!!.

    Mercedes should have that printed on when making the car.!

    I got the sunroof back in there in a working perfect condition as the
    last big thing to fix, and days later the engine stops... aah old cars are fun!
     
  11. DREAMER NO2

    DREAMER NO2 Senior Member

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    W124 2.6E M103 1989
    info

    Hi as i have gone through this problem ,can you sit in your car and , turn it over and see if revcounter is moveing ,it it is that will rule out your crank sensor .MAIN THING IS HAVE YOU A SPARK ON THE PLUGS. Dont think you have said this. Also you google --- how to check your coil with digital meter .I was lucky at the time some member gave me the way to check it out on the forum. If you have fuel in there it should start, and if you have spark Can you find an old plug, pop it in a lead, any plug will do. Insulate it with a rubber glove and insulated you from the high voltage that in the lead as its spun over.Have you a spark from a metal part on the manifold bolt.Dont let it run long .Just enough to see the spark. On your EZL check all conections you will find some push on plug caps,remove check them for damp , check to see they are making contact. Must say if you guys with older type cars dont have a spare EZL i would get one now as they are getting very expensive. Other one to watch is alarms and immobiliser faults will stop your car from starting.
     
    Last edited: Jan 19, 2015
  12. OP
    Rob Linus

    Rob Linus New Member

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    Your Mercedes:
    230TE (1991) (W124)
    I have now checked that the rpm-meter on the dash is moviong when i turn the motor. It showed over 600 rmp when engine is almost starting. I have checked the big connector plug both on the VDO and EZL, and they look like new.
    No dust or anything anywhere. Looks like they were never opened or leaking since the car was made.. So what I had planned for the next move is this:

    I will replace the rpm-censor, the ign.coil, distributor house & rotor arm, spark plug wires, and the spark plugs themself.
    If the engine is still not starting after that. .. Then I will try a VDO from a car thats okl. If still no start, .. then there is only one thing left in the car that can prevent it from starting. The EZL, as far as i can understand tho.

    This little piece of electronix, i found on
    http://www.reservedeler24.co.no/ (sparepartsn for german cars)
    and it cost round 26000 Norw Kroner. And thats £2256 !! I will not be surprised if it is just that EZL that is broken.

    Well new parts hopefully soon, Ill find out more then...
     
  13. DREAMER NO2

    DREAMER NO2 Senior Member

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    W124 2.6E M103 1989
    info

    Rob can you not try an EZL first . It will cost a few bits of gold if you buy all the parts .After ezl then buy one item at a time. It will be quicker if you get a check by a Mobile auto electric he will check it at home.Then you will know just what to purchase .I had this same problem ,and as you i did all that i knew .Replacing this and that, took coil to a garage and had it checked ,it was ok.Then i even purchased an ezl ,at £80 secondhand . As i could not get it up and running i booked a visit. And it was my immobiliser in the end.It was removed and it was ok after.
     
  14. DREAMER NO2

    DREAMER NO2 Senior Member

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    W124 2.6E M103 1989
    info

    For other Mercedes owners ,with classic cars .A tip ,if you can get a EZL unit for your car , then i would get one.The price for these are getting high now due to them not being made anymore. But you may be lucky and find one at M/Benz at the nice price of £800 plus ,but thats if they can locate one for you. Just check Ebay for the price that one will cost for your love and joy. Just get one a spare ,it wont eat anything in you garage .Even if you dont need one right now. But get one with the exact same numbers as yours.
     

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  15. OP
    Rob Linus

    Rob Linus New Member

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    I called a guy around here that have a small car auto workshop and asked if he had any of these ezl's layin around, and he said he might do but had to check first. If he find any, I could borrow them and test on my car no problem.

    those parts did I order 3 days ago anyway.. I just hope that the auto guy finds some and if mine are dead that he gladly sell his to be for nothing.!

    I seem like the reason for the sudden engine stop is soon to be found and can be dealt with. :)
     
  16. OP
    Rob Linus

    Rob Linus New Member

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    Ok guys, the engine is now running !!

    Tried 2 used EZL's that should be working (in case one of them dident) but them both did nothing new so my ezl was then thought to be ok.

    I got to say that the spark plugs is making a spark when checked outside
    of the engine by turning the key. But a spark is not a spark it seems.

    I ordered new coil and ignition cables. Changed the coil and the ign cable running from the coil to the distr.
    That was IT! The engine started! I have not checked the old and new coil with ohm meter or with insulation tester, my guess is that the old coil has partly collapsed, making enough voltage to spark the plugs but not enough to ignite the fuel all the time in all cylinders ... The engine is almost starting with the old coil, it gets a cylinder ignited now and then but not enough to get the engine running properly.

    The first reply to my problem was: "do you have a spark", and I did!!
    arrrgh, If only that old coil had died instead of getting sick, this would be solved on the first reply.. Oh well, I know aheck of a lot about this car now and thats really worth something. Cant wait for the next thing to break, now im ready..haha

    Thanks to all of you that helped me getting it running again!!!!!

    R.Linus.
     

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