Help Needed - W124 Starting Issues

Glen Johnson

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Hi all,

I'm hoping that somewhere within this pool of knowledge, there might be an answer, or at least a clue to point towards the root of my problems.

I've got a 1996 W124 E280, with 200,000 miles on the clock. I've had it for two years and in many ways it's been great, but has had some issues (mostly wear and tear), however it has now had a problem starting for a couple of months which seems to be stumping everybody, mostly because it's intermittent and because no error codes are being recorded. Most of the time it just turns over but won't fire. The fuel system and ignition system have been tested and are working, but when this issue occurs something is stopping the fuel from making the final leg of it's journey through the injectors and therefore firing the engine into life. Occasionally, the old girl forgets that she has this problem, fires into life as soon as I turn the key and runs like a dream, until she decides to let me down again. The local mechanic I've been using is very good; he's an older guy with many years of experience and a slow and methodical nature, but he can't solve it at the moment, and until she decides to fire up again, I can't even get the car back to him.

  • The crank shaft sensor has been changed.
  • The loom has been rebuilt around 18 months back.
  • The ECU was sent for repair and reconditioning 18 months ago.
Can anybody help?

Thanks,

Glen
 

ajlsl600

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clk3202001,sl6002003 with everything regrettably sold ,A class 170cdi auto. NG/TF1800 ML250
If you squirt some fuel(carefully ) into it or spray a little easy start as its cranking does it fire up? If u didnt do this before,ask yr mechanic friend about it first.this will prove it as a fuel not getting into cylinders issues.does it smell of fuel when trying a cold start ?
Are you getting a good cranking speed ? I think the ecu will be looking a signal from crank sensor so it knows engine is cranking within limits before giving signal,power to injectors.
A Dodgy fuel pump relay ?
Someone will be along who has had this or similar issue.
Research how cold start is governed.sometimes another injector in inlet manifold controlled thru ecu and temp sensor.utube is often a source of guides on such matters .just ideas I briefly owned a ,280 GE 4x4 but I had no bother with it except keeping the fuel tank full.!!
 

DREAMER NO2

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W124 2.6E M103 1989
Cold start wont stop the engine from starting. It would start hard but it will start . First make sure you have a spark. Check crank posision sensor ohm . Also check fuel tank cap seal when you unlock you should have a vacuum so the seal must be good .All the fuses need turning in their holders .,. or replace if they are the old white metal type .But i have know people have the ecu rebuilt only to pack up in a few years time .You cant beat an original used one in this case .
 

DREAMER NO2

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W124 2.6E M103 1989
Do you have an ovp relay?, if you do pull it out and give it a shake . If it rattles then open it up and resolder all the joints inside.
 

mattkh

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Assuming it is a petrol car.
Car alarm/immobiliser playing up.
Ignition switch playing up.
 

DREAMER NO2

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Mat yes i never gave it a thought,, it was the imobilised that had me stuck one year after i took the winter cover of .Put the battery on and spun her over it would not start --- no spark . I changed everything i had in the arsenal ,still no joy. Auto electrics found the problem .He took 2 wires off and it fired right up .I removed the alarm and imobiliser and fitted my own .
 

RhodieBill

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Check your Camshaft Sensor - this is primarily for Starting. If faulty - which is commonly intermittent - it fails to tell the fuel system to send fuel. The fuel System will not know the Engine turning if the Camshaft Sensor fails.
 

AndySlade

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Check your Camshaft Sensor - this is primarily for Starting. If faulty - which is commonly intermittent - it fails to tell the fuel system to send fuel. The fuel System will not know the Engine turning if the Camshaft Sensor fails.
Also make sure it is cranking over fast enough. May be a weak battery or as in my case the starter motor past its best.
 
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