240D Starting problem
 

I have a 240D (1983) that has a starting problem. It starts fine on the first try, but upon a second try there is no response in the starter.

There is a push button switch located on the upper portion of the arm of the clutch. Is this a safety switch, and could it go bad?

I think that switch is actually on the brake lever and its the brake light switch. There is no safety switch on the clutch.

Check your battery cables with particular attention to the ground wire....and be sure to check the engine to chassis ground wire. Sometimes an additional ground strap from a a starter bolt to the chassis is helpful in the case of an older car too.

That safety switch idea was invented about fifteen years later.;)

Tom W

I had a '90 Eclipse that had that safety switch, so they were around in the '80s, I dont know about MB though, as I have never owned an MB manual.

Like tom said, check your grounds as well as clean your battery terminals, that should correct the problem.

12 volts is one thing, however if the starter isnt getting the amperage, you arent going anywhere (dont ask how I learned that one).

Mine did that for a while before the starter failed. Then it did it again for a while before the second starter (@#$% Malaysian rebuild) failed. Got another one from a different source. So far so good.

On second thought, maybe it was a @#% Indonesian rebuild. Anyway it was rebuilt somewhere they shouldn't be rebuilding starters.

Thanks guys for the response. I have checked the ground and the battery terminals. All are clean and solid. After examination I found that the glow plug relay box located near the front drivers side headlight, is "hot" all the time, even when the ignition is off. Is this normal? Also, I double checked, there is a push button switch under the top portion of the clutch, not the brake. I am getting a manual this week to figure out what it is.

yea trust me, its not fun to accidently leave the car in gear, pre-glow and try to crank.;) car lurches forward mad style. As for a switch under the clutch pedal. Never seen one. Maybe the PO added a switch there for some reason:confused:

I noticed you listed a 240D Euro. Does that mean that it was designed to operate in Germany? I have the opportunity to purchase another 240D which has no American options, but was shipped over by someone. What are the differences?

I must revise my problem with starting the 240D. Now it doesn't even crank. The battery has been charged, the glow plug light comes on, but I am not for sure all the glow plugs are working. I will try to check them next week. In the meantime, does anyone know of a reason a motor wouldn't even crank, even if the battery is charged? I had the starter checked out at the local parts store and it seemed to work fine. The battery also checked out as fine.

Many thanks to everyone for your help. It turned out to be a bad starter. The confusion was that is worked sometimes and didn't others and then finally gave out all together.

In the archives you can find my experience with a starter that had no reasonable pattern for when it decided not to do anything...
We need to keep in mind first that these starters are working against a 21 to 1 compression ratio from the day they are installed...
Second... many people own cars which have had multiple owners and have no idea how old the currently bolted up stater is... it could actually be original to the car... they are tough machines with HUGE brushes on them ( the pieces of carbon which press against the armature are called brushes )....
When mine was acting up I took it to a small farming town which has great level one repair people... and asked them to take it apart... and I was able to stand there and see it actually open up...not that I don't trust repair people... I am just describing the situation... they showed me that the brushes were still ' OK'.... but the three little screws on the end which keeps the superstructure which holds those brushes in line had very seeable electric arc burns on it... and they were clearly loose....
So while we always start with battery condition, wire condition, key switch...
AT SOME POINT in time we just have to admit these very sturdy starters can just wear out... or need fixing... I was lucky that they had an already rebuilt starter which had not been picked up .... which saved a round trip to pick up mine.... but part of the point is that if you can open up yours... it might be as simple as loose screws... tighten and keep on dieseling.... or repair other stuff while you are there...

If your car has cruise control, I believe there is a switch on the clutch to disengage it when you press the clutch. Europeans, at least in those days, were unable to order a manual with a cruise control installed by the factory. The TUV guys thought it was dangerous. Jim

Very good information.

Also remember there is a phenomenon known as 'Heat Soak'. This is very well known to owners of older Ford Pickup and others also. As a start motor gets very hot in summer especially from radiant heat and conducted heat transfer from the bolck and exhaust manifold etc it becomes more sluggish. Hot conductors do not conduct as well as cold conductors. Remember what superconductivity is?? On a hot day when I try to start my aged 1979 F350 after a long trip it barely turns over. I wait, let it cool and it is back to new. This explains at least one contributing factor to the initial post of this thread. The best way to think of this problem is to imagine you are an electron swimming through a tortuous passage from the pos terminal all the way back to the neg terminal. Just the corrosion you encounter at the grounding bolts alone are like big rocks.

Great forum guys.......

Thanks everyone for your help. I found out what the switch was on the clutch pedal. The above post is correct, it was for disengaging the cruise control. The starting problem ended up being the starter.

This however leads me to my next question concerning the cruise control. For that I will make a separate post.