W220 2001 S Class Intermittent Starting Problem

[dragonwales]

No problems cold starting in the mornings. Then if the car is left for say more than 2 hours, it will not start - as if the immobiliser has not been deactivated, ie engine will not even turn. It will take about an hour plus and then the car will start without a hitch !!

Ended up in Merc garage two weeks ago and they blamed a power drain which was minimal but traced to a fault with linguatronic device. This has now been deactivated. Problem has reappeared. Has anyone come across similar ? Merc garage is no help as sod's law, I cannot replicate the fault when I leave the car with them.

 

[Pookis Dad]

Non Starting

Did they do a diagnostic last time? If so, did it flag up any fault codes?

If not, it may be nothing more than a dirty connection at the starter solenoid. More than likely the ignition wire is either loose or has a high resistance connection.

The heat of the engine would cause it to get worse.

Next time it craps out, wiggle the thin wire at the starter and try to start it.

It's worth a try

 

[dragonwales]

The diagnostic did not flag up any fault codes - at least that's what they reported back.

Why should the ignition wire suddenly become loose ? I will try as suggested next time it happens and report back. Btw, I am a novice at this, so where can I locate this wire ?

 

[television]

Could this be the crankshaft sensor, I take it that the engine is turning over,though it is not starting

 

[BlackC55]

Diesel?

Petrol?

 

[slow jams]

would bet crank sensor all day long as malcome said, about 60 quid, and easy to fit, sensor dont always show up on 220 and 163 models unless you crank it at the time its mucking about, can give you part number if you need it?

 

[M6AJJ]

Agreed, mine showed similar symptoms, and then finally packed in. Had to be recovered by Mobilo, taken to MB dealer and provided with a new S Class, when at the dealers they drove it off the transporter and replaced the sensor and all has been well since. Mind you, kept their new S Class for 2 days, seemed a shame to give it back too soon.

 

[Pookis Dad]

Starter

I read it that the engine wouldn't turn over!!!

If it is cranking but not starting, then I would agree with the sensor theory.

 

[dragonwales]

Sorry Television / M6AJJ, Pooki's Dad is correct. The engine would not turn over. Just to reinterate, I can turn the key or press starter button (keyless), instrument board all lit up ..dials (temp, petrol) all working, but nothing happens. It felt as if the immobiliser has not been turned off. When I explained to MB garage, they said that this was not possible as soon as the alarm was deactivated, so did the immobiliser.

Black C55 - car is petrol. S600 Limo model.

 

[greatw]

Have you checked the brake lights are working? Thats exactly what my S500 does if I hit the keyless go without holding the brake pedal down. From reading on the forum, the brake pedal switch seems to be less than reliable whilst being (fortunately) cheap to replace!

 

[dragonwales]

Yes Alex, everything works....lights, comand unit, tv, radio, sat nav, windows, sunroof etc..it's just the immobiliser has not been deactivated even though I have entered the car !

 

[greatw]

Have you specifically checked the brake lights though.
There is an interlock on the keyless go system that will not allow the car to start unless the brake pedel is depressed (or at least a bit unhappy ) The way the car know if this is the case is from the brakelight switch. If this is faulty, the signal will not get sent and therefore everything will work except the starter.
It is one of those things you don't tend to check as they are a pain in teh ass to do but it is worth ruling out!

 

[dragonwales]

Yes as I can see the brake lights in the reflections from the office windows. Thanks for the suggestion anyway.

 

[Uncle Benz]

As I read this, I do not believe that you have ruled out heat-soak into the starter motor. You need to check that power is supplied to the small terminal on the starter when the fault exists. You may be able to get your garage to rig up a temporary line with a bulb, so you can tell if power is getting that far. If the bulb will not light when you crank, there is a problem in authorisation, or control before the starter. If the lamp lights, but no starter operation, you need a new starter motor. Hope this helps.