1975 450sl

[promuzzy]

trying to get this car running please help thankyou all in advance
first the little crank/pulley sensor is damaged doesn't the car need that to start?
second how to check if the cold start fuel solenoid is working?
i have more questions but please help me with these two

Thankyou
Kevin

[AlanTbird]

seems like no one is home? LOL Ive been lurking cause my 75 has no spark or injectors firing but I was able to test the cold start valve with my noid which is a light you connect to the plug...my cold start is the ONLY thing I get any action out of so far! i was look for the crank sensor on mine and couldnt find it....want to enlighten me?

[RadioTek]

Where is the sensor you are asking about? My '75 doesn't have one. If it's a D-Jet injection system, it shouldn't need one.

There's a lot more active a 107 forum over on Benworld.org at http://www.benzworld.org/forums/r-c107-sl-slc-class/

This forum tends to be more oriented toward the newer models, although many people frequent both.

[GaryF]

The sensor is there on Euro models and is just used to feed the diagnostics connector next to the distributor. It doesn't play any part in controlling the engine.

[BrianB]

Anyone have a tip of where I may get one? Pertronix does not make one for this year...and does anyone know if the lower set of points here can be adjusted indepandantly of the top ones? ( also may be interested in buying a distributor that has points to get this baby running again !@)

[cth350]

Brian, there are zillions of posts here about D-jet (or D-jetronic) fuel injection. The thing to remember is that they didn't replace the basics, namely the need for air, fuel, spark and compression. The EFI system simply makes checking these things a bit fun.

For instance, does the car run for 2 seconds if you spray ether into the intake? If not, don't worry about fuel, fix the ignition.

The second thing to check is fuel pressure. Is the system reaching 32psi when you turn the key from 0 to 1 (forget 2, which activates the starter). If the fuel pressure gets to 32psi, does it drop back to zero when the key is turned back off?

There will be dozens of little things to correct. Each fix will bring the car closer to the wonderful animal a benz can be. You will be revisiting each little thing and making them better.

As for the two sets of points in the distributor, start by simply listening to the injectors with a stethescope (or holding a screw driver to the body of an injector). If you can hear it click when you turn the key, then most everything is working about well enough to not consider the distributor, brainbox or under the hood wiring as being totally shot.

But you have to get past the ether and fuel pressure tests.

HTH -CTH

[BrianB]

60-70 miles an hour before the aftermarket circuit board broke (my fault)--now with the "custom" pertronix electronic module it runs very poorly, not well enough to get on the road

[BrianB]

I really do appreciate the tips.....anything and everything will be invaluable....love this car!

[BrianB]

The last mechanice who worked on it said fuel pressure was good ...think he said about 30

[Pooka]

A tip for checking if injectors are clicking...

I use a thin metal rod, maybe 3 or 4 mm thick, and place it to the point I want to hear. On the other end I place the pick-up end of a cheap stethoscope and put the ear buds in my ears.

The rod transmits the sound up to the pick-up pad and my ears being full of buds keeps out all the other noise.

Also, if the rod slips, as it could do, and hits something that could throw it out of the car then it just flies clear and not through your head.

This also works for checking out if a hydraulic lifter has failed.

You can buy a tool that is already made for this if you wish.