Turn The Key and Nothing--Sometimes - PeachParts Mercedes-Benz Forum

sublettd · #1 10-02-2007, 08:39 PM

Scratching my head over this one. I've replaced the starter, neutral safety switch and ignition--in that order--while trying to figure out why the '81 300D (non-turbo) doesn't start sometimes. Talked with my son and he seemed to think there was a loose wire or a bad ground. So, I went out and looked things over.

I noticed that where the negative battery cable connects to the chassis that there was rust all around the bolt. So, pulled it out and cleaned the area, as well as the bolt, as good as I could and screwed the bolt back in. Don't know if this fixed it or not, but can't think of any other options.

Anyone have any other good ideas in the event this didn't fix the problem?

running-snail · #2 10-02-2007, 08:50 PM

IIRC I've read something about shifter bushings being worn and not allowing the safety switch to recognize you're in park or neutral - do a search and see what you find - might be something there.

Also a hammer rap on the side of the starter? Again, do a search and see what comes up on this.

sublettd · #3 10-02-2007, 08:56 PM

Snail,

Shifter bushings are 6-8 months old. Back-up lights work when shifting out of park, which would seem to indicate that the shift lever is not the problem--as I understand it anyway.

Tapping the starter was the fix for intermittent starting on the SL, until we discovered the ground wire was almost burnt in two in three places.

Thanks though.

Scott98 · #4 10-02-2007, 09:00 PM

You have two ground wires. The engine to chassis (which you've checked) and the negative cable off of your battery. Check them both.

Other suggestions would be a bad solenoid or bad ignition switch.

Let us know what the problem turns out to be.

Scott

sublettd · #5 10-02-2007, 09:13 PM

Scott,

I believe the ground I check was from the battery to the chassis. Didn't know there was one for the engine to the chassis. I'll try to find that one.

The starter and solenoid were changed. When I turn the key to the start position, there is no click or anything. If I'm not mistaken, there should be a click if the solenoid was going bad.

The ignition switch was replaced yesterday. I suppose I could have gotten a bad one, but not really ready to entertain that idea.

Appreciate the suggestions though--and will post the fix once it's discovered. Thanks again.

MBeige · #6 10-02-2007, 10:00 PM

Just a guess. Check the fuse on the GP relay. Maybe it's just loose.

sublettd · #7 10-02-2007, 10:10 PM

What is the GP relay--General Purpose??? If so, are you talking the overload protection relay, or another? Thanks.

unkl300d · #8 10-02-2007, 10:36 PM

glow plug relay.

maybe your valve adjustment is off.
I had that problem with a '79 240D once.

sublettd · #9 10-02-2007, 10:42 PM

Understand glow plug relay. Thanks.

Valves just adjusted a couple months ago. It's definitely an ignition--or lack of--problem.

This must be my quarter for gremlins. Still chasing one in the SL that is causing it to run rich. Just dropped off the computer that goes in the passenger footwell to my mechanic. He said something about it controlling the frequency valve. The frequency valve controls the..., which controls the...

Gotta love these Mercedes!