W124 300CE 24 non runner

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I was told 2 things kill EZLs, heat & damp.
Damp, I doubt. My 300CE-24 has lived outside for a quarter of a century and it's pretty damp here. In fact, it' effing torrential. EZLs are very well sealed.

Heat, yes, it must be dissipated to the bulkhead via a thin, even layer of good quality heatsink compound. Repeated every decade???

And those outside influences. My money (Christ, so much of it!!!) is on the coil. The output transistors die when loaded excessively. Don't know much more.

R
 
Damp, I doubt. My 300CE-24 has lived outside for a quarter of a century and it's pretty damp here. In fact, it' effing torrential. EZLs are very well sealed.

Heat, yes, it must be dissipated to the bulkhead via a thin, even layer of good quality heatsink compound. Repeated every decade???

And those outside influences. My money (Christ, so much of it!!!) is on the coil. The output transistors die when loaded excessively. Don't know much more.

R
but if the coil is dead then i should get no spark, and I did
 
I can get a EZL unit for £500, but if its not this then its another £ down the drain.

If you've got another EZL, fine. You might need it one day. When you get it, install it with its nice new heaatsink compound and make sure you still have a spark.

And it's not down the drain. If it works, it's still worth 500, or more!!!

By the way, what part number? For others who might be interested.

R
 
but if the coil is dead then i should get no spark, and I did

I had spark and something killed 3 EZLs. Misery.

Coils are much cheaper than EZLs so get a good one. MB original, I suggest. Easy for me to spend your cash, I do understand.

I cannot stress enough how important the HT system is. I've now replaced everything from coil to plugs with genuine MB replacements. even to the extent of replacing a 9 month old Bosch distribuor cap that was showing signs of cracking. As said, everything now is genuine MB and the cap, after 3 years, still looks new. I looked the other day.

The right stuff should last you another 15+ years, assuming MB quality is what it was. My fingers are crossed. So are my bank manager's!!!

A bit of history. Back in about 2003, I replaced distributor cap and rotor with Bremi parts. Why did I do this??? 6 months later, they came out in favour of cleaned up , 19 year old originals that worked well until I could afford more. The Bremis left us stranded outside the bar tabac and the owner had to drive us home. It started the following morning but was spluttering by the time I got home. Bremis out.

My basic message is this: if you are serious about the car, spend the money. If not, prepare for grief. Just my 2c worth.

If you need plug leads, they are not listed by MB. But the parts are. Mine were made up by MB in Bochum and they fit like a glove. NOT like the recent Beru or NGK aftermarket stuff. 2 to 3 times the price, sadly.

Finally, I have heard about 3rd party plug lead vendors. And good reports too. But I have no knowledge.

R
 
Damp will enter the EZL unit where the O rings on the round plugs are perished or cracked. If you've never changed the O rings on your EZL have a close look at them. If they are original they will be useless.
 
have a close look at them.
All looks pretty good. I went through a programme of buying up increasingly rare parts, amongst them EZLs. On arrival, each would be cleaned thoroughly. Often, the o-rings would disintegrate. I replaced them with a bit of silicon grease to protect. Also, thoroughly cleaned surface to prepare for heatsink compound. Cleaned all contacts with electrical contact cleaner.

These units are pretty well sealed and that is probably why they are practically impossible to repair.

R
 
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some piccys of the innards and why they cant be repaired!

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That vid is useful for those replacing heatsink compound. He seemed to apply enough but not too much. And he confirms that the foil is not necessary. My thought is that the foil was purely for production efficiency. The EZLs were supplied to the assembly plant with compound and foil - clean and easy. No mess and the operator just slapped the EZL into place. Why they say it shouldn't be removed is a mystery as, to my way of thinking, the foil might increase thermal resistance. I've never bothered.

I have a brand new NOS EZL (made in 2003?) and the compound was fairly dry so I've removed it and put the EZL back into stock with a little syringe of compound ready for installation.

I have had both the early and later EZL in mine and never noticed any difference.

RayH
 
basics: spark fuel and air. Verify that all 3 are making their way into the cylinders.
 
.....and compression....
 
Does your car currently run resistance spark plugs? Mercedes of that vintage have resistors built into their plug leads and do not require resistor plugs.
NGK - NTK web.site
When you say you are getting a spark at the plug is that in open-air. If the spark is weak in open air it may not fire under compression In a cylinder----- are all the plugs a healthy colour?
 
These cars are fairly easy to diagnose except if the fault lays with the fuel injection system, not many garages now know their way around that now. I would suggest you get the car back and verify the basics before you throw any more money at it.

1. Does it have a good spark?
2. Do BOTH fuel pumps run when the ignition is turned on? And do they run when your cranking the engine?
3. Make sure there are no obvious vacuum leaks, especially the rubber boot under the air flow meter.
4. Be carefull with this one.... disconnect the fuel line from the blue cold start injector and aim it into a jar/bottle ect, crank the engine and see if you get fuel spray out.
 
Does your car currently run resistance spark plugs? Mercedes of that vintage have resistors built into their plug leads and do not require resistor plugs.

Resistor plugs should not cause a 'no start' but are not recommended. Genuine MB, NGK and Beru replacement leads have 2K resistance in the suppressor caps. Order MB suppressor caps were 1K.

The recommended plugs are:
A0031596703 (Bosch) Superceded by: A003159670326
A0031596803 (Beru)
A0031597103 (Champion)

When I order MB plugs, I always receive these: A0031596803 (Beru). They are made in France. My usual MB original supplier lists them at 3.90€ each.

R
 
The MB specialist has checked compression and they found 2 cylinders being down on compression but this in my books should not stop the engine starting.

They have replaced the park plugs, I don’t know with what made.

The fuel pumps are new and both run on prime, fuel comes out from the injectors.

The car was running without a problem and one morning it refused to start. So I do not think is an air leak.

The issue is that the MB specialist can not start the car and is sitting in the garage since Jan 2023. Before that tried to start the car by the usual means, easy start on the intake etc. Checked that I get fuel on the engine, sparks, distributor, cables, crankshaft sensor, without luck. I decided to send it to a MB specialist and its seating there since then.

Now they are waiting to get a donor car in so they can swap thinks over and find what it wrong with it. Personally I don’t think they have the will to fix it hence not doing much on the car. I need a competent mechanic that can solve this issue and put the car back on the road so I can use it.
 
I need a competent mechanic that can solve this issue and put the car back on the road so I can use it.

There are specialists around London. Wayne Gates gets good press but I have no knowledge.

There must be others and this forum should recommend someone. Try posting another thread asking for specialists in and around London who support the older cars.

In your shoes, I'd get a low loader and haul the car back home. You might even find someone on here that could visit you.

R
 

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