ignition switch question

[Ann]

The ignition switch seems to have gone bad on my Pagoda once my mechanic changed over to the electronic ignition. It's very hard to start now, was not previously. Took it back to mechanic and he re-checked the wiring. And everything seems to be in place, so suspects the ignition switch in the dash. He called our local MBZ repair shop and was told it's nearly impossible to obtain an ignition switch for a 1970 SL. Any resources on this part?

I can still turn it over, it's difficult to start now.
I turn it over ALL the way then back off just a bit, and it struggles, but turns over. It won't start just by turning the key all the way over- like before. Takes cranking & backing off, and I don't like to do that.
Does this sound like the ignition switch, or ?

Ann

'70 Euro 280 SL silver
'06 BMW Z4 Montego Blue
'98 Jeep Gr.Cherokee (125K mi.)

[merrill]

Ann,
sounds fishy, did the car start ok before?

on the 66 the "switch" is a mechanism that screws to the back of the ignition.  for the 66 the switch was avaailable but the ignition mechanism (key, lock with switch) is probably harder to get.

If you call the mb classic center you will be able to get the true story on availability.



Matt
Austin Tx
66 230 sl - "white"
78 300 D - Blue
98 C230

[al_lieffring]

Ann

Have your Mercedes dealer check part #

116 462 00 93

for availability, This part number is hard to find unless you know to look for it in the steering parts group instead of electrical where you would expect to find it.



Al Lieffring
66 230Sl
New blue top just arrived
new gas tank on order

[Ann]

Thanks Guys!

Yes the car started perfectly prior to the installation of the electronic ignition (naturally). The install mechanic said he suspected either a bad unit for the (Crane XR 70) system. OR the ignition switch (not the keyed part)might have gone bad.

Coincidence? Hmmmmmm <G>. I think not.

Anyway in a couple weeks I have my local MBZ guy looking at several things (like a heater) and a 80K service, so I'll put this on the ever expanding list.

The GREAT news is the car is running fantastically since the K & N air filter was put on. She is smooth and doesn't chug anymore at long signal lights.This could be a side benefit of the electronic ignition, too. But right now I'm mad at the Crane (just kidding).

Ann

'70 Euro 280 SL silver
'06 BMW Z4 Montego Blue
'98 Jeep Gr.Cherokee (125K mi.)

[upside2k]

Hello Ann,

I have the Crane ignition on my car. It has been on the car for about 10 years and functions well. In fact, the car starts faster than original.

I instinctively don't believe in this kind of coincidence. The first thing to check is the wiring diagragm for the Crane--double check it. Pay particular to the grounding of the ignition. Because grounding conductors carry virtually zero voltage, even the slightest corrosion or poor connection will cause a failure of current flow. Grounding is probably responsible for 90 PERCENT of electrical failures. Then check starting(cranking) voltage at the terminal on the switch side of the ballast resistor, the side closest to the firewall( I don't have a pic of this resistor).I have assumed that your battery is properly charged---you shouldn't.

Voltage at this terminal(ballast) should be battery voltage or very  close( about 13 volts). If it is less, then you have some resistance in the switch, the switch wiring, or most likely a ground( perhaps the mechanic accidentally moved something). The resistance(failure) could be in the switch but I doubt it. The only way this might have happened would be a short through the switch during the install( I have seen this more than once).  

Then check the ballast resistor for resistance. If the ignition capacitor( At the coil) has not been removed you will have to disconnect one side of the resistor or you will get a false reading. My guess is that the resistance is about 3-5 ohms. With the ignition on, you will probably read about six volts on the load side of this resistor because this coil is probably a six volt coil. Twelve volt coils generally have a parallel resistor wire for starting. I have looked at the wiring diagragm and see none.

I should have prefaced all of this by saying that I have never analyzed this problem on this car so these are generic tests---but it should bring the desired result.

If all of these check out OK, then you should check the cap,  and the clearance specs, mounting, et cetera, of the sensor in the distributor.I always assume that everything has been installed incorrectly; this is not an insult to your installer, only good technique. We all make simple and obvious mistakes and somehow our brain will not let us revisit the error until all else fails. I think any good tech will agree. How many times have you typed a sentence, proof read it four times, and still did not notice a missing word---this is the same experience.

I hope this helps, John

[Raymond]

Ann,
I'm with John.  The coincidence is unlikely.  A switch failure wouldn't affect the quality of starting, just whether the connection is made or not.  It could have gone intermittent, but why just now?  

The tech support at Crane is thorough and friendly.  If your tech doesn't solve the problem with John's tips, have him call them. Once the installation issue is solved, you'll be happy with the system for a very long time.

Ray
'68 280SL 4-spd Coupe

[al_lieffring]

One of the biggest problems in making a correct diagnosis on an electrical or for that matter any problem, from the point of view of the mechanic (I still bristle at the use of the term technician) Is to make sure that the complaint of the car owner is completely understood and not obscured by the use of vague descriptors like the ever popular, "it has a short" or "sometimes the car doesn't want to start". Trying to find out the driver's actual complaint sometimes can seem like an interrogation, but It is important so time is not wasted chasing down trails that have nothing to do with the problem.

In this case my take on the problem is not that the starter cranks the motor over and the new ignition system doesn't make it run.
But rather that when the key is turned to the farthest right position the starter is not engaging unless the key is turned slightly back to the left.

As a mechanic I have often seen components fail that have nothing to do with the work performed, and have had to eat these unrelated repairs for lunch, just to keep the peace with the customer.

It wouldn't surprise me if this is one of the reason for many shops not being willing to take on repairs of these aging cars.

The notion that a 40 year old part's failure always has to be the fault of the repair shop is just a little bit absurd.

That guy with the greasy fingernails and a dorky looking rented shirt, more often than not, is trying to help you, and isn't trying to take away as much of your money as he can get away with.

Al Lieffring
66 230Sl
New blue top just arrived
new gas tank on order

[upside2k]

I would have to agree with you wholeheartly on most of your comments. My adage is: If you spend 80 percent of your time diagnosing the problem you will spend 50 percent less time and energy fixing it.  I am not a professional in this field, but my effort was to suggest that your best bet is not to count on the customer, or a practitioner, to give you good diagnostic information. Grill them and be a good detective, but ask your question in many different ways and DON'T ASSUME ANYTHING. The human mind is always anxious to defend its own efforts first. From medicine to auto repair this is a reliable maxim.

Anyway,Ann; let us know how you make out.    

quote:Originally posted by al_lieffring

One of the biggest problems in making a correct diagnosis on an electrical or for that matter any problem, from the point of view of the mechanic (I still bristle at the use of the term technician) Is to make sure that the complaint of the car owner is completely understood and not obscured by the use of vague descriptors like the ever popular, "it has a short" or "sometimes the car doesn't want to start". Trying to find out the driver's actual complaint sometimes can seem like an interrogation, but It is important so time is not wasted chasing down trails that have nothing to do with the problem.

In this case my take on the problem is not that the starter cranks the motor over and the new ignition system doesn't make it run.
But rather that when the key is turned to the farthest right position the starter is not engaging unless the key is turned slightly back to the left.

As a mechanic I have often seen components fail that have nothing to do with the work performed, and have had to eat these unrelated repairs for lunch, just to keep the peace with the customer.

It wouldn't surprise me if this is one of the reason for many shops not being willing to take on repairs of these aging cars.

The notion that a 40 year old part's failure always has to be the fault of the repair shop is just a little bit absurd.

That guy with the greasy fingernails and a dorky looking rented shirt, more often than not, is trying to help you, and isn't trying to take away as much of your money as he can get away with.

Al Lieffring
66 230Sl
New blue top just arrived
new gas tank on order