Author Topic: ignition problem  (Read 77 times)


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  • W116 Enthusiast
  • Location: Quorn Sth Australia
ignition problem
« on: 11 March 2019, 08:25 PM »
Hi guys, just a question on ignitions. My problem is when I start the car the key won't return to the normal position but keeps engaging the starter and now need to turn it back manually. Any one know the answer? I'm thinking its the electrical plug behind the ignition switch but would like a bit of info.
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  • W116 Enthusiast
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Re: ignition problem
« Reply #1 on: 11 March 2019, 10:59 PM »
Definitely the ignition switch. I just changed mine and it fixed it


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  • W116 Enthusiast
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Re: ignition problem
« Reply #2 on: 12 March 2019, 03:44 AM »
De-grunging it is worth a try.

-Disconnect the battery.
-you can try flushing it with WD40.
-use a rag underneath to catch the drizzle.
 : note the colour
 :if looks grey and murky you are flushing out graphite
-insert the key and rotate progressively to the various positions right up to ignition/ start...withdraw..clean the key blade..repeat the drill .
-make sure you relieve the load on the  steering lock  as you move thru the process.
-finish off with a blast of Aerostart or equiv into the barrel. Let it "dry" for a several hours before reconnecting the battery and attempting a start.
a start.
If the key/lock gives no improvement, then it is highly likely one of the little springs in the lock tumbler has fritzed and you need a new one.

DO NOT use graphite powder to lubricate a key lock.

Diesel 617

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  • 1980 300SD 0M617.950
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Re: ignition problem
« Reply #3 on: 12 March 2019, 08:15 AM »
1980 300SD
2 OM617.950 complete with transmissions
1980 450SEL Transmission (for sale 150kmi 100$ + freight)

In my imaginary garage
European 1974-76 450SEL 6.9 Green Velour