1997 W202 C200 turns over, won't start

[phb10186]

Hi everyone,

I have not used the forum much so hi to all. There is a fault with my car....

History:

The car has never been reliable really. It is a 1997 pre-facelift C200 Elegance with the flip out key and credit card key, all with buttons.

I will write a full explanation, so here it goes:

I have the red and green lights on the drivers door and rear view mirror. To my knowledge, since owning it from 1999 and 17,000 miles, I have never seen the red light on either come on.

The car turns over, there is a spark present, but it will not fire up. Ok so I was also thinking fuel or immobiliser too.

History:

It has now got 50,000 miles on it, and I have had electrical glitches every year or two since I have had it - bummer. This is the first time it won't start though.

I have had the coils replaced about 2 years ago.

I turns over well, and the spark is there.... not sure about fuel, but I have a feeling that the imobiliser is at fault. No fuses are blown in the fuse box.

Any suggestions???

-Ben

 

[Aussie Nick]

If you have spark at the spark plugs (Are You Sure?) more than likely there is a fuel starvation problem. Have you checked the fuel filter. It might be gunked up? otherwise the fuel pump may be suspect.

 

[phb10186]

Definitely have a spark on all 4 plugs. Green light on rear view mirror flashes as I turn it over.

.... Just checked this... there is no fuel comming through the fuel rail!!!

Is fuel cut-off by the immobiliser?

 

[dragon]

You need to check whether the batteries in your key fob are at least 3 volts else replace the batteries. There is a ring around the ignition key, make use it pushed in and not loose. You also need to synchronised the key, press the key fob three times and turn to ignition to position II, the green light on the rear view mirror should flashes it not something is wrong.

 

[Aussie Nick]

I dont think it is the fob or the immobiliser. If it was either of these two, or both you would not be able to turn it over or get a spark.
My focus would be on the fuel filter. There is a possibility also that the injectors are fouled but if that was the case you would probably get some signs of ignition. I would suspect the fuel filter or the fuel pump.

 

[phb10186]

Fuel pump is OK, I have just checked it, turning the car over releases fuel on to the road via the fuel pump.... so that looks OK - but when reconnected, no fuel to the fuel rail???

Does the immobiliser block fuel to the fuel rail at all, or does it block the spark.... that would be a great help!

 

[dragon]

In the first instance, you have to maintenance the car according to Merc guideline.

When was the fuel filter change?
When were the spark plugs changed?
Is the key fob batteries OK and did you synchronise the key fob?
Have you try using the credit card key, it should start, if it doesn't then it not the immobiliser security system problem.

plus many more

 

[Aussie Nick]

I think the immobiliser blocks the spark not the fuel, but have to confess that I am not 100% sure. Another member maybe able to assist you better on this one.
AFTERTHOUGHT If the fuel pump is working i cant see how the immobiliser could block fuel supply without shutting down the fuel pump.
Maybe you need unscrew / loosen some of the injectors to seee if fuell is coming through to the cylinder head.

 

[phb10186]

both red LEDs on the RVM and door do not appear to be working..... no fuel comming out of the injectors, therefore no fuel in to cylinders.

Car does not fire up with any of the 3 keys.

I have been reading that if the red lights in the rear view mirror and door fail, the immobiliser system fails and that car won't start... is anyone familiar with this problem?

 

[Aussie Nick]

Try disconnecting the battery and leave it off for half an hour.Then reconnect it and see what happens.

 

[phb10186]

done it, battery was flat for over 2 weeks!

 

[Aussie Nick]

Did you actually disconnect it by taking the cable clamps off both terminals.
What is the condition of the battery now?
What were the circumstances of it going flat. Its sounds that the sudden cold weather has killed your battery. Even though you have recharged it and it shows some signs of life it might be quite dead.
Do you have a hydrometer to check the condition of the cells?

 

[phb10186]

Tried it already... the battery has been disconnected for 2 weeks recently!

Have been looking on here and there is a lot of bad things writted about the immobiliser on this medel and year od w202!!!

I think the fact that both my rear-view mirror and door red LED are not working, might be the root of some immobiliser issue!

 

[phb10186]

Battery is A-OK, I'ts only a year old and is a new type sealed unit

 

[dragon]

Is your system battery fully charged? At least 12V. If red led is flashing, then key to the transponder is not OK, as I said check, the ring around the ignition is pushed in.

Either the ECU or immobilier is faulty.

If you don't have the expertise send it to a Merc dealer who can check it out for you in just a couple of minutes, it won't be expensive, just a couple of quids.

It save you from all the hassle guess it here and there.

If you have a diagnostic tool, use it, this is the first step a Merc dealer will do.

 

[phb10186]

Neither of the 2 red LED's work, is this the probable cause of the non-start issue?

One red LED is in the RVM, the other is in the drivers door handle... both kaput!

The immobiliser no longer beeps when locked or unlocked.

The RVM red led never worked since 1999 when I bought the car. The drivers door handle has since stopped working, but I don;t know when.

I have read something about increased resistance when the led's break, which jams the immobiliser ON.

This does sound very logical..... but why do I have a spark, but no fuel comming out of the injectors, even though the fuel pump pumps fuel out in to the road when I disconnected it???

What circuit is the immobiliser breaking, it tells me that is does something in between the fuel pump and injection manifold. I will reiterate that I have a spark on all 4 plugs.

 

[Aussie Nick]

I dont think there is any thing else between the fuel pump and injectors. Normally with immobolisers you will not get a spark or a crank if they are engaged. I think you are thinking of the maf manifold and that controls the flow of air.
Hang fire and some other members with perhaps greater insight may assist.

 

[dragon]

It a known problem if you disconnected the battery and connect it back the Scorpion security module malfunction due to spikes. You may have to PM Malcolm or Bigasotonuk to bypass the Scorpion security module in order to start the car or get yourself a new module with keys from scrap yard or eBay if you are lucky.

 

[bigasotonuk]

Hi,
The immobiliser on mine i believe cuts the power to the ECU, mine still sparks when immobilsed too.
When i had a similar fault on mine, the red LED in the mirror had never worked but the car suddenly started playing up, i spoke to a MB tech and he said that all the LED's would all have to work before any diagnostic work could be carried out i managed to get the red LED replaced (normally you have to buy a new mirror) and this fixed the immobilser problems.
A new mirror is approx. £130, I would get a second hand one try Merc-man in Southampton, or if you feel competent try replacing the LED yourself. The door sensor when i replaced mine was approx. £40 from MB.
Both items very easy to fit.

 

[phb10186]

Thats good stuff Ash, why does the immobiliser fail when two LED's blow, rendering the car permanantly immobilised?? And if that's is the case how can MB design (or sub out) such a weak system.... Why do the red LED's go and not the green ones???