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73 450sl won't start

7K views 22 replies 10 participants last post by  cushjbc 
#1 ·
Sprayed off the car at the car wash(hood Closed0 then it would not start. It turned over fine. I backfired once. Had it towed in. Could I have sprayed the Ignition Control Module up front and caused this problem. I have printed out the ignition testing procedures and will start testing in the morning. Anyone had a similar problem? Any help appreciated.
Jim
 
#5 ·
Jimmymike65,

I have taken EZLs apart to see what is inside. From what I saw when doing it, they are sealed pretty well. There is a rubber seal around the edge and a heavy varnish coat on the electronics. If the case has corrosion, I guess it could happen. If you get that far before solving your problem, open it up and take a look.

The early switchgear is very expensive to replace so I hope that is not your problem; Trog's solution is a good one otherwise.

Pictures of a later model EZL:
 

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#22 ·
dear,

i have some issue with my ignition system 0227051014, same as on your picture,
i'm trying to repair my unit, i made an elektronic drawing of it, but 2 componts i could not determine, 2 black round balls on the circuit board.
i put a red circle round the components, could you help me with identifying them, and measuring them out with a volt meter. i don't know if they are a capacitor or diode
Art Font Gas Electrical supply Urban design

thx
 
#6 ·
73 450sl won't start

Car fixed..turns out the car wash was not the problem. The last mechanic to install the points had the connection wire installed wrong. The shaft was rubbing it and it shorted out. Back on the road, thanks for the input.
I am going to buy a Pertronix and eliminate the points.
 
#9 ·

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#11 ·
German restoration enthusiasts I have spoken with tend to adhere to originality more than others. I met several at the Middle Rhein Auto Club rally in Cologne a couple of years ago.

The real issue driving owners to Pertronix is wear on the ignition distributor shaft bushings. This wear allows the shaft to wobble a few mils which causes contact points to wear at the nylon foot that rides the shaft. Owners get tired of setting dwell at the points. Pertronix hall effect transducer produces the same low energy signal without a mechanical interface at the distributor shaft. The alternatives are rebuilding the distributor or sourcing a new one.

I agree with the assertion that the EZL and low voltage points are reliable in a design spec distributor. I do not see how Pertronix, also a low voltage system (same voltage, less noisy) would in any way cause the EZL, coil or high energy side of the ignition system to fail more than contact points.

What I do see is that Pertronix is not made in Deutschland.
 
#13 ·
The only negative I have read about with the Pert I, is the possibility of the Pert itself burning out, if the distr stops in a certain position. And this is only a problem if the ign sw is left on, such as during testings. But it is easy enough to disconnect the Pert when doing other tests, so doesnt seem to be much of a problem.
 
#14 ·
For what it's worth, although I have a Flame thrower coil, I cant see bypassing the MB electronic switch gear while it still works. My thinking, was that if Pert failed, I could just put points back in. But haven't had any problems.
 
#18 ·
No problem with tach if you keep original switchgear (EZL?). And if you bypass switchgear, many here have got working tachs by adding a resistor to line to tach.

I see you are looking for replacement switchgear ("EZL"). Do you know there is something wrong with yours? Only ask, because that would be difficult to diagnose without having a good one to test with.
 
#16 ·
I kept the EZL and have a working spare from a salvage car. In fact my Pertronix came from a '72 300 SEL at the salvage yard. I had it on hand and decided to try it one day instead of resetting my dwell. I haven't worried about points or dwell since.
 
#20 ·
If you search "Pertronix" in this Forum, you will find plenty of threads and even more opinions about using them in our cars. 1885 is, I believe, the correct Pertronix 1 number. I have a '75 which, for some reason I do not completely understand, seems to be a more difficult conversion than the '73 or '74. After reading all the threads, I just regapped the points and left it alone until another time.
 
#21 ·
Hi guys & gals.....so I hadn't driven my '74 in a few years and decided to charge up the battery and go. It started it was pretty rich you could smell gas & fumes. I decided to give it a tune-up. Changed plugs, wires, distributor, rotor & fuel filter. The car would not start. Yikes I noticed I screwed up the firing order! Fixed the problem still won't start. Checked for spark between the coil, all good. Changed points, checked for fuel at rails & check. This thing will still not start. Anyone have any suggests? The fuel pump comes on and I changed out the coil 3x (just wanted to be sure it was getting 12v) and both resistors. This thing still will not start. PLEASE HELP! Thx!
 
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