Coil packs

[SteveW]

Hi

I've just bought a 95' C280 sport about 3 weeks ago and it has blown 2 coil packs in this time. The previous owner had the same problem but not in such a short space of time.

Would anyone have any idea on what could be causing this??

Cheers

 

[janner]

What plugs are you using?
Is it the same coil pack gone twice or two at a time? If so which two?

 

[kth286]

SteveW

It is probably the engine wiring harness inner insulation starting to disintegrate.
It is a known problem with this engine around 92 ish to 96 ish.

The insulation gets very hard from heat and where it is buried under the coils cover it starts to fall off and the two wires to each coil will short and blow the coil/s.
You have to check it out quickly as it can blow your main ECU (computer) with costly consequences (around £1000 ish)

AS it is the car probably needs a new engine harness at around £500/600 ish and fitting on top of that.
You can fit your own, I did. There are some 22/23 connections to unplug and plug together again and access is very tight to some connections, but take your time and it's easy if you lay the new harnness over the old as you go.

Your first step is to check the condition of the insulation going to the coils, by cutting the thin outer covering with a nail scissors and looking inside.

Do you see the inner insulation cracking ? and flaking off ?

The problem starts when the plugs and coils are changed as the brittle harness has to be moved each time and this makes matters worse.
So, do not be in a rush to change coil without checking insulation first.

What miles car done?

What's your location ?

Hope this helps.

Regards

 

[big x]

Good post.

Is it true that MB sourced the harness from a Swedish company that used biodegradable plastic? If so those involved should have their paypackets docked for all the replacements

adam

SteveW

It is probably the engine wiring harness inner insulation starting to disintegrate.
It is a known problem with this engine around 92 ish to 96 ish.

The insulation gets very hard from heat and where it is buried under the coils cover it starts to fall off and the two wires to each coil will short and blow the coil/s.
You have to check it out quickly as it can blow your main ECU (computer) with costly consequences (around £1000 ish)

AS it is the car probably needs a new engine harness at around £500/600 ish and fitting on top of that.
You can fit your own, I did. There are some 22/23 connections to unplug and plug together again and access is very tight to some connections, but take your time and it's easy if you lay the new harnness over the old as you go.

Your first step is to check the condition of the insulation going to the coils, by cutting the thin outer covering with a nail scissors and looking inside.

Do you see the inner insulation cracking ? and flaking off ?

The problem starts when the plugs and coils are changed as the brittle harness has to be moved each time and this makes matters worse.
So, do not be in a rush to change coil without checking insulation first.

What miles car done?

What's your location ?

Hope this helps.

Regards