Mercedes E280 ignition problems

[JohnnyMerc]

Hi there, I have a 1995 E280 merc. Initially it wouldn't start up at all, but AA came around and said it was because of the battery being too small. So I replaced that and it started up first time like new. However, after a few days of having the new battery it's started playing up again. It's a struggle starting it and I now have no idea what's the problem. Perhaps the petrol pump? I don't know...

I got told it's not the alternator, so that's not the problem. It's also not the spark plugs as they're new.

Any ideas?

[grober]

.

I got told it's not the alternator, so that's not the problem.


Have you had the alternator output tested? Is the engine slow to turn over? Switch on the headlights---- do the lights dim when you turn over the engine? Is the engine offering to fire or not?

[JohnnyMerc]

Thanks for the reply.

Yep, the alternator output has been tested - it's perfect.

Engine isn't slow to turn over, no.

Lights don't dim, no.

Engine doesn't fire at all.

There is, however, a humming noise from the engine every time I start it up, but it eventually dies down. So I still have no idea what the problem is.

[jaymanek]

well it really does sound like the alternator...

does it start if you jump start it?

[JohnnyMerc]

well it really does sound like the alternator...

does it start if you jump start it?

Well, I got told it's not the alternator, but I'll have to double check it, I suppose...

And yes, it does start when jump started.

[jaymanek]

alternator then, or another faulty battery or loose connection maybe?

[television]

Do the simple test with a voltmeter, if the car runs on 13.8 volt then the alternator is working

[JohnnyMerc]

I had the alternator voltage checked and they said it's running fine.

I'll have another new battery put in, and have the connections checked over.

Thanks for the help.

[Mercedes cozy]

My dad had the same sort of problem as your car.

He change the Over protection relay behind the battery is a silver colour unit with a fuse on top. About £60 from MB new. Worth a try.

Hope this helps.

[grober]

My dad had the same sort of problem as your car.

He change the Over protection relay behind the battery is a silver colour unit with a fuse on top. About £60 from MB new. Worth a try.

Hope this helps.


Funnily enough thats what I was going to suggest next. It may also be tied into the alarm system if you have one. replacing it would be a good first step. Here's a picture of one type for a w124 http://www.w124.org/entretien/OVP.jpg

[Mercedes cozy]

I have a spare one, worth a go.