W140 S280 will not start.

[Tan]

Hi

We are having trouble starting my Dad's S280, the battery was flat so we tried to jump it. It sounds like its trying to start, but just doesn't turn over.

We thought initially that it may have run out of petrol, but have put quite a lot of petrol in it now, but the gauge is not moving and when we connected the battery the alarms sounds for a while (very quietly though).

My thoughts are that it could have been the immobiliser, but I am not sure how to override the alarm, the remote fob unlock the doors but does not seam to deactivate the alarm.

Another thought is that it could be the fuel pump, how would I go about testing this?

Does anyone else have a thought of what it could be?

Many thanks

Tan

 

[BlackC55]

Don't jump it.

Use a jump pack and you may need two of them in cold weather to get it turning over.

If the alarm sound quietly than the battery is low.

 

[abecketts]

Our neighbour who has a superb low mileage 92J S430 (89k) has the same problem as he uses it so little that the battery goes flat. I'm told that you can take out some of the electrics and then it gets v expensive. I have suggested he fits a trickle charger to keep it topped up or flog it to me as the W140 is growing on me.

 

[Tan]

We don't use ours that much, but intend to try and start using it more regularly to keep it running, that is of course when we work out how to get it started.

 

[jonnyboy]

As said use a boost pack, then when its connected cycle the lock/unlock a couple of times to ensure the immobiliser hasn't kicked in.

 

[jaymanek]

Your jump leads are not strong enough... either buy some very good jump leads or get a decent booster pack, maybe a local garage will help you...

failing that AA or RAC cover?

 

[Tan]

I called out Green Flag and they tried to start it but still nothing all they could suggest was towing it to a local garage.

They think it could be either the fuel is not getting through, either because of fuel pump issue of an immobiliser.

Is there a way to disable the security system? Its a standard Mercedes not an aftermarket system

On our old 124 the system came with a key to turn it off, do the newer systems, this car is a '98 have the ability to turn these off easily.

Regards

Tan

 

[grober]

The only thing I can suggest is opening the " black box" if you have one??? That's the integrated power distribution bus module that contains many of the cars electrics normally located under the bonnet. It contains several control ECU type units. If you take off the lid check to see if any of the fuses are blown/corroded. There's a fuel pump unit in there somewhere. I assume you have the M104 straight six engine?

 

[jonnyboy]

Tan.
First things forst get the battery disconnected and fully charged overnight. Connect the battery and try to "cycle" the locking as I have said.
The charged battery + being disconnected for 30+ mins may reset the problem.

 

[Tan]

Green flag came out again today and used a fully charged jump pack, the alarm seams to be turning on and off, or at least the red light is.

The car still won't start and the fuel gauge is showing empty, though the car has had a fair amount of petrol put in it, if the immobiliser isn't disabling would that effect the fuel gauge, or is it more likely to be the fuel pump?

If the fuel pump how can I check this? Relays were also mentioned, where would these be?

Many thanks

Tan

 

[grober]

See post #8 the black box is outlined in red.

 

[Tan]

Hi

I lifted the black box area and there is nothing underneath, any other ideas where the relays may be?

 

[grober]

There appears to be 2 wiring types for the w140 280 model one has the " black box"as I have said- where that is under the bonnet don't know? I thought that was it from the picture but obviously just a bit of cladding - possibly further back beside the brake servo then?? If there's only the older conventional type of fuse/relay box there then the fuel pump relay may be located in the boot. http://translate.google.co.uk/trans....ru/mercedes/F/#1/&sl=ru&tl=en&hl=en&ie=UTF-8