240D No starter turns into bobsled start
 

Car is 1983 240 with 4 speed manual.

Notices this morning that the crank was a little weak when I went to start the car. No big deal, figured it was just cold. So I went to the grocery store on the way to work and came back out to the dreadful sound of the starter click and no crank.

I pop the hood and connect my jump pack worth of 14v to see if I have a battery problem. Nothing changes. Just more starter click. Next I grab the tire iron and beat on the starter. Nothing changes. Finally I had to go because I was going to be late for work so I did the bobsled start. Ran beside the car with the door open in parking lot isle then jumped in it to bump start it in 1st gear then took off. Went back home to swap out the cars and the car would start with the key, but it sounded a little week.

Battery is new, the starter solenoid is new as well. Wiring is all cleaned up and I don't think I have a ground issue. Is it just a simple starter swap? I'd hate to spend the $200 on a starter for it to be something else. I love this 240D but can't chance driving it somewhere where I can't get a running start to bump start it.

Did you try jumping the terminals on the connector on the right fender (if 240d's are the same as 300d's). Sometimes the ignition switch connections get dirty.

Didn't try to jump the terminals.

I don't think it is ignition switch related because it everytime I hit the key I clearly hear the solenoid clicking but the starter not engaging.

Off topic a bit but I would.be using 3rd gear when doing a rolling start much eadier on everything.

That's true. I should be doing it in 2nd or 3rd.

Well, tried to start it tonight. Turned the key and the starter turned over but barely had any juice at all. Hooked the jump pack up and it didn't make a difference.

So either I drained the battery earlier in the day or something is draining the battery.

Could be:
1. weak battery due to a charging problem,
2. bad solenoid,
3. bad starter, or
4. ground/wiring/connection.

Put the car in neutral, set the emergency brake and chock the wheels. Then,

Check the voltage at the battery key off, then check it while cranking. If it goes way down the battery is dead. Would like it to stay around 10 or so volts while cranking

If the voltage stays up, check it at the battery cable attachment at the solenoid. If much lower voltage than across the battery, then the cable is bad or the ground is bad. Try using a jumper cable from the battery negative to the engine block temporarily to eliminate/find a weak ground.

Check the voltage at the starter positive cable while cranking, if low, bad cables/connections. If good then,

Check the voltage at the starter motor where it connects to the solenoid. If low, bad solenoid. If good, bad connection at the starter solenoid connection. If battery voltage is to the starter motor where it connects to the solenoid and it does not crank well, the starter motor is bad if the grounds are good.

Good luck!!!

Thanks Sug. That's my plan tomorrow.

Really sounds to me like a dead starter motor.

Think I solved it.

I pop started it again because nothing was going to be able to jump it.

Once I got it started and drove it around I put a load tester on it. 12.4 with the lights on.. 12.6-12.7 without the lights. So I got the hammer out and put the end on the alternator belt to ''tighten'' it while running. Shot right up to 12.8.

So sounds like I have a loose/worn alternator belt or just a bad alternator. Voltage regulator is new. So that's out. I'm going to change the belt and tighten it and see if that fixes my problem.

I think the original no start was just not enough juice to even spin the starter.

.1v is literally nothing. I'd suspect a coincidence rather than the hammer-tensioner actually doing anything there.

Based on what you've tried and what's happening, I'd strongly suspect a problem with the starter motor itself, or more likely a poor ground between the engine and frame/battery.

FWIW;

Voltage regulators other than BOSCH brand, will never charge sufficiently .

I experimented with many different brands and none ever went above 13VDC no matter what , a BOSH branded one OTOH, always changes better and no more cold weather hard starting issues .

It's a simple thing to do and only costs a few dollars more .

This statement:

And this statement:

Don't agree with each other.

You've tried several times to jump start the car and failed each time. That points to a starter problem, not a battery / alternator problem.

? Seriously / .

No one here knows basic starter teting ? .

Look at the front end of the solenoid, there are two large copper nuts ~ jumoer across them and the starter motor should *instantly* (not wind up to speed) begin to spin fast , not cranking the engine .

If it Doesn't either the battery is dead/low charge or the starter is needing service .

If it spins right up , try jumpering the thick red wire to the upper large nut, this will bypass the entire electrical system and force the starter to operate and crank the engine .

FWIW, batteries often die without warning so either get a good jump with real jumper cables, not those shyte 4Ga. ones everyone carries or an analog voltmeter and see what the battery shows when the start's load is applied to it .

How you diagnose this will affect the co$t and reliability of the repairs you do .

The starter just clicking was only the problem the first time it didn't start. I've started it a dozen times today since without issue.

I see. It's a HELLA on there now. I assume the OEM Mercedes voltage regulator is Bosch? I can buy an OEM one for literally 75 cents more than the Bosch one.

I don't think anything will jump start these cars unless it's massive. My little 375 jump pack won't make a difference and I had a Jeep Cherokee try to jump me this morning and it did nothing. It was barely start the crank and didn't have enough juice to even think about cranking.