300SDL starting problem.... - PeachParts Mercedes-Benz Forum

BenzB0y · #1 09-25-2008, 08:52 PM

This morning I woke up to find that my 87 300SDL won't turn over... When I turn the key to accessory everything runs stong and works properly, but when I turn to ignition, everything electronically slows down (wipers, buzzer, lights dim...) glow plug lights come on also... so.. any ideas?? The engine tries to start, but doesn't have enough power to turn over, how should I try jumping it tommorow to see if its just the battery??

Thanks!

Oracle12345 · #2 09-25-2008, 08:55 PM

It could be a weak battery. how old is the battery?

Hows your starter?

How are your glow plugs and hows your compression?

Did you try the block heater?

you can have your battery tested at autozone or advanced.

BenzB0y · #3 09-25-2008, 09:01 PM

Battery is about a year old, but is a knock off...

Not sure about the starter hope it's not, how much do the cost??

Glow plug light comes on and goes out, compression is usually great... the problem started last night as I was leaving a friends I started the car, but noticed that it barely turned over, ran great back to my house, but now it won't start.....

Hatterasguy · #4 09-25-2008, 09:03 PM

Sounds like a bad battery. Test the voltage and see what its showing.

If it is call Mercedes roadside and they will come install a new one.

BenzB0y · #5 09-25-2008, 09:07 PM

Would jumping the battery be a good or bad idea to see if that's the problem???

IVIuzzy · #6 09-25-2008, 09:07 PM

i am having the same problem with my 300d, it does it intermittently. i just cleaned the battery connections with a wire brush, and i cleaned the connections on starter and main ground the same way. i also used conductive electric grease. i just did this tonight. but car seemed to start well, i tried several times.

i know these diesels need a lot of power to turn over.... i figured cleaning all the connections would help get the power she deserves...

i will stay tuned for updates, though, i dont think its that easy of a fix.

Hatterasguy · #7 09-25-2008, 09:09 PM

Sure you can jump it, if that does it, its the battery. If not than it could be the ground, or starter.

If its the starter usualy you will hear a loud click, and than nothing. Giving it a sharp whack with something hard will usualy get it to engage, so you can get home.

Oracle12345 · #8 09-25-2008, 09:17 PM

Quote:

Originally Posted by Hatterasguy

Sure you can jump it, if that does it, its the battery. If not than it could be the ground, or starter.

If its the starter usualy you will hear a loud click, and than nothing. Giving it a sharp whack with something hard will usualy get it to engage, so you can get home.

hammer works pretty good

Hatterasguy · #9 09-25-2008, 09:19 PM

Yes they do!

Luckly on the 603 the starter is on the drivers side, so get under a 617 first and take a look...than go change yours and you will feel pretty good about the job.

Brian Carlton · #10 09-25-2008, 09:29 PM

Quote:

Originally Posted by Hatterasguy

Sure you can jump it, if that does it, its the battery. If not than it could be the ground, or starter.

Naturally, you already know that the alternator is good and is charging the battery..........right.........??

That's how you can be certain that it's the battery............???

You already know that he has a low voltage condition.........and, therefore..........the starter won't turn at full speed. Why would it be the starter?

Oracle12345 · #11 09-25-2008, 09:35 PM

Quote:

Originally Posted by Brian Carlton

Naturally, you already know that the alternator is good and is charging the battery..........right.........??

That's how you can be certain that it's the battery............???

You already know that he has a low voltage condition.........and, therefore..........the starter won't turn at full speed. Why would it be the starter?

I did that on purpose to cover the realm of possibilities and to educate him a little. I know its the battery but If he encounters this situation in the future hell know where to check.

Brian Carlton · #12 09-25-2008, 09:45 PM

Quote:

Originally Posted by Oracle12345

I did that on purpose to cover the realm of possibilities and to educate him a little. I know its the battery but If he encounters this situation in the future hell know where to check.

Personally, I like to analyze the data and approach the problem with the item that has the highest probability of success.

In this case, while the battery is a prime suspect, you can't make any determination without a measure of charging voltage.

You certainly cannot suspect glow plugs or starter with the information presented.

IVIuzzy · #13 09-25-2008, 09:48 PM

to test the charging voltage, just use a voltage meter. test the amps on the battery while the car is running, it should be 14. or around that, i beleive a perfect alternator is 14.3. i wouldnt worry about an alternator unless it is below 12 amps.

Brian Carlton · #14 09-25-2008, 09:57 PM

Quote:

Originally Posted by IVIuzzy

i wouldnt worry about an alternator unless it is below 12 amps.

I'd worry if it was below 12.5 volts.

BenzB0y · #15 09-26-2008, 11:48 AM

Hooked up the battery charger and primed the injection pump a couple of times and it attempted to start the first time, but was a little cold. The next try after a few minutes of charging and she ran good and strong as usual, and the power seat surge went away, I can adjust driver seat forward without it sliding back from surge...

I cut the engine off after driving about 30 minutes and it started back up with no problems... I revved the engine a little while ago to help the battery stay charged.. I think it helped... thanks again for all replys!