My 300D not starting well - PeachParts Mercedes-Benz Forum

AntonyB · #1 05-31-2005, 10:48 AM

Hi
I'm having problems with my 300D W123 1978 model when tring to start it. I have just had my alternator fixed with new brushes and bearings which is supposed to be running well. The problem I have is when turning over the key some times the starter motor kicks in then other times it is just dead and nothing happens. My dash lights are on. After a few turns the starter motor tries to kick over again, but I keep draining my battery. Thanks for the help in advance.

boneheaddoctor · #2 05-31-2005, 10:59 AM

Could be a bad Solenoid itself....or a bad starter....a bad starter will draw far more current than a properly operating one.

TX76513 · #3 05-31-2005, 11:05 AM

Have you checked you battery condition? Most parts houses will perform the check (for free) if you don't have the equipment. Battery's loose the CCA's after time -

AntonyB · #4 05-31-2005, 11:17 AM

Thanks for the fast replies.
My battery should be OK as the electrician who fixed my alternator checked it out. Thanks for the suggestions on the Solenoid and possible bad starter.
Are the starter and solenoid more likely the problems, or could there be something wrong with the actual ignition key switch?

boneheaddoctor · #5 05-31-2005, 11:22 AM

Quote:

Originally Posted by AntonyB

Thanks for the fast replies.
My battery should be OK as the electrician who fixed my alternator checked it out. Thanks for the suggestions on the Solenoid and possible bad starter.
Are the starter and solenoid more likely the problems, or could there be something wrong with the actual ignition key switch?

How many miles are on the car....its always possible its the ignition switch...but thats less likely in my mind...

If the starter was cranked long and hard and overheated the insulation will break down and shrt out......Lot of people kill starters due to other problems that cause a hard start.

t walgamuth · #6 05-31-2005, 10:49 PM

i concur with the bonehead... more likely solinoid... i have changed the ignition switch before but solinoid more likely.

Mister Byrnzoil · #7 06-01-2005, 07:11 AM

check your connections. Disassemble clean and reassemble battery, starter and ground connections. (and coat w/ dielectric grease if you are prone to corrosion)

Also, when its dark out, have a friend start the car while you look under the hood for any sparks or arcing.

Does it make any difference whether you start in P or N?

cheers,
Robert

lofat · #8 06-01-2005, 11:16 AM

Does this happen with fresh starts? Like when you come out in the morning and try it?

If it is only happening after you have been running it, shut it off and then try to restart it?

are you pulling the key all the way out between starts?

AntonyB · #9 06-05-2005, 08:38 AM

Hi guys, thanks for the suggestions so far.
I've cleaned the battery terminal and some terminals around the Solenoid. I'll have to get the car up on a hoist to get the rest in the next week. When trying to start the car now I get a nice click which is indicating the Solenoid is doing something, however in the last few days I'm hardly getting the car to turn over . Even the battery light and the preglow light dosn't come on the dash now. The battery is fully charged.
On the clock is 462068 KM
The problem doesn't seem to matter whether it's cold or warm.
I had a friend look in the engine when dark to see if there was any arcing and found nothing obvious.
No difference with the problem in P or N starting positions.

t walgamuth · #10 06-05-2005, 11:49 AM

if you are getting a click it means that the solinoid is closing the switch but the contacts are not making a good connection. usually this means they are corroded. on the old amercian cars you could take the solinoid out and turn the contacts over and start over on them. i am thinking you cant do this on the benz though.

prob could get this symptom with a loose wire too. between the solinoid and starter.

sailor15015 · #11 06-05-2005, 12:26 PM

My 85 300D is experiencing the same problems. Most of the time it starts but every tenth start or so it does the same thing, the solanoid clicks and the lights dim like its getting current but the starter won't turn over. It will start, however, if I jump it from another car for about a minute or two. I started a thread on this about a week or two ago but I can't seem to find it. It was recomended to me that I should clean the engine grounding strap but that is connected where the engine and transmission bell housing meet. Needless to say its torqued down really well and I can't get it to come loose. A friend of mine suggested that I ground the engine out somewhere else so I'm off to try that and if that doesn't work off comes the starter. By the way, I went to O'rielly's and the battery, which is three years old, tested out at one hundred percent and the alternator is putting out thirteen and a half volts at 700 rpm like it should. I think I've pretty much exhausted my options unless someone else has any ideas. Any thoughts on the subject would be immensly appreciated.
Thanks

t walgamuth · #12 06-05-2005, 12:32 PM

sounds like you are on the right track. although a ground strap that wont unbolt is suspect. sounds as if it may be corroded on.

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