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500se has no spark

7K views 7 replies 4 participants last post by  Heintz 
#1 ·
Hi guys,

I have a 1990 500se (South Africa) and absolutely love this car! It has a new problem which is beyond my level of knowledge - which is not much due to this being my first Benz... My problem is this: The car had stood for a while due to the hydraulic hose on the SLS springing a leak and me waiting for the new part. I fitted the part, which has left my car without an oil leak :). I then had another challenge as the battery wouldn't start the car if it stood for three or more days. I decided to change it for a new battery and fitted it today. When I tried to fire her up, the engine cranked, but alas, there was no fire-up! I checked if there was fuel coming through, which there is. I poured some fuel directly into the air regulating disk sitting on the intake manifold, but still no fire-up :crybaby2:. I then proceeded to test whether I had power on the coil. I used a 12V tester and it showed that there was power on both terminals that are connected to the coil. I then removed no 1 spark plug lead and had a friend swing the motor... No spark! This is where my ideas ran dry and I decided to come to the computer and ask the fundi's if they could assist. Oh yes, maybe it is worth mentioning two other small things which in my opinion, don't relate to the problem, but we'll include everything just for the sake of being thorough. I seem to have had a rat under the hood which chewed its way through one or two wires, which I have repaired. Secondly the car had an alarm fitted which was disabled and not working when I collected the car from the previous owner. Don't know if this will add any value. I would greatly appreciate if someone could point me in a direction of what to check and how I could restore the spark to my Benz...

Thanks!

Heintz
 
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#2 ·
If you had mice under the hood, chances are there are more wires that have been chewed on. I would remove the battery along with the battery tray and inspect that area first. There are many places rats/mice can chew through wiring, though I would re-inspect everything in the engine bay and in between the firewalls. I would remove the aftermarket alarm if it no longer works and tidy up any loose ends.
 
#3 ·
Might be the EZL, ignition box. I believe it takes reading from the crank position sensor, and affect the coil from producing spark. Or something like that maybe.... i cant remember. lol

But yes you should inspect all wiring and remove the aftermarket alarm system as benz560sel4u2nv suggested.
 
#4 · (Edited)
Hi JW560sec,

Thanks for the reply. Please excuse my ignorance, but what is an EZL, and where is it located? BTW, where can I find these CDs everyone keeps on reeferring to? I have tried in vain to get them in the RSA and to try and mail order them is quite risky unless they sent to me with DHL...

Something else that bugs me is the fact that the tester is showing power on the coil, but why is there no spark on the plugs? I have checked the wiring as far as I could trace them and it would seem as if the damage was minimal - thank goodness! I will however remove the aftermarket alarm system, as I am well aware that they become problematic after some time. If memory serves me correct the previous owner told me that it was not in use when he bought the car...
 
#6 ·
#7 ·
I found it! Thanks for the 'directions'! I believe it seems to be the 'rare' eight pin unit. I really don't think this is my problem though. I drove the car to where it is now parked, it didn't die on me or splutter to death... I have a very strange feeling that it is something small. Like I said, I will iron out a few of the loose ends and go from there. Thanks for the help and pointers guys, it is highly appreciated!
 
#8 ·
Ok, so just in case there is someone who has a similar problem, I found mine... I didn't add it in my previous posts, but one of the screws that hold the distributor cap down, had seized up and I just couldn't get it to budge. I tried everything and then the Benz died on me... Well, I am happy to report that after replacing the coil, which I think may have been faulty or well on it's way to becoming faulty and making plans to find the all elusive eight point/pin EZL, I may actually have fopund the reason why the car has no spark - the distributor cap is in pieces! I managed to get the screw loose after days' of battling and on opening the distributor cap it came apart, literally in pieces. I will replace the cap on Monday, as everything is closed here on a Sunday and then hopefully, the Benz will be back on the road. Thanks to the guys who have sent me suggestions and remedies.
 
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