Occasionally when i turn the key to start, nothing happens. i will try again and it will turnover and start. any ideas on what might be happening when the key is in start position and nothing happens?

thanks
cliff hubbard

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1983 300d~250k Sold
1985 300d~185k
1999 Volvo V70 wagen 109k
2001 Dodge Ram 1500 78k

does the solenoid make a clicking noise at all on the no-start occurrences?
otherwise it seems a problem in the key switch mechanism, ie. not making good
contact.
it's time to deal with it now rather than later as i did (and have to drill the whole key switch out ...)

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1984 300D Turbo - 231k....totalled 11/30/07 RIP

there is no sound from the solinoid. no sound at all. when it happens, i will sometimes put it in drive and then back into park, try it again, raddle the key, try again, eventually it will turn over...
as far as dealing with it, what do you have in mind?
thanks
cliff

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1983 300d~250k Sold
1985 300d~185k
1999 Volvo V70 wagen 109k
2001 Dodge Ram 1500 78k

Over last summer, I installed a 'hard-start relay' with great success.

I think this may be your problem. Of course, if you put it in neutral and it starts it could be your Neutral Safety Switch.

Basically the hard start relay takes the load off of the ignition wiring without adding a separate starter switch. I can explain further if necessary.

id like to hear more on the hard start relay. just say search or point me to a link if you have already discusseed it here. thanks.

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What Would Rudolph Do?
1975 300D, 1975 240D, 1985 300SD, 1997 300D, 2005 E320 , 2006 Toyota Prius

There are four connections on the common bosch-type 30amp relay I used as a hard start relay.

Two go to the coil (which is an electro-magnet) which connects the other two together. One of these (does not matter which) goes to ground, and the other one goes to the wire that comes from the ignition which would normally attach to the starter's solenoid.

Then there is two more connections left. One (doesn't matter which) gets connected to a constant 12v source, the other connects to the starter's solenoid.

This way, the relay gets the signal from the ignition and essentially connects the starter's solenoid to your constant 12v source. Then when the engine starts, and you let off the starter (with the key) the normal way, there is no signal to the relay and the contacts separate and that starter motor stops.

It takes the load off of the ignition wiring which would normally be seeing about 5-7 amps to operate the solenoid probably only sees less than 100 milliamps to operate the relay.

I have the same problem on my 85 300td. At first I thought it was the stater but connected a jumper at the connections under the hood and with the key on it fires fight up. This problem only happens occasionally I think its in the switch.Its on my to do list.

It would be easier (and cheaper) to try a hard-start relay first.

It will take the load off of the switch, and should solve your problem.

it sounds very much like either the key switch and/or the neutral safety switch as others have said, or the starter itself. jump the starter from the block on the passenger side fender between one of the large screws and the small screw using needle nose pliers. the starter should spin no matter what the key position.
as far as dealing with the key switch it comes in 3 parts .. you can replace the electrical (back) part separately if the other parts are good. look at dieselgiant's article about this.

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1984 300D Turbo - 231k....totalled 11/30/07 RIP

i dont htink it is the starter for i have jumped it from under the hood with out problem. i will look more closely at the switch. also interested in the relay mod. what is the bosch part # that you used, 985 300SD Sady ?

thanks for all the input...

cliff

__________________
1983 300d~250k Sold
1985 300d~185k
1999 Volvo V70 wagen 109k
2001 Dodge Ram 1500 78k