Question on type of M119 ignition systems...

[suginami]

I know on W124's with the M119 engines, they all have two distributors, one for each bank of cylinders.

On the W210 1997 E420, I believe it had a different ignition system, doing away with the distributor, and using a coil pack with each plug having its own coil wire, like on M104's.

Did the M119's on W140's have a similar evolution, and if so, does anyone know when the break appeared?

One would think that not having the expensive of buying new distributors and spark plug wires every 30,000 miles or so would be a huge savings in maintenance costs.

Also, what are the advantages of the "coil pack" system (for lack of a better word), over the old traditional distributor-type ignition system?

[suginami]

Here's what I mean. The engine code changed mid-stream.

1992-1994 S500's have an engine code of 119.970.

1995-1995 S500's have an engine code of 119.980.

[gerryvz]

Originally Posted by suginami

Also, what are the advantages of the "coil pack" system (for lack of a better word), over the old traditional distributor-type ignition system?

I was going to say that 1995 was the break point for the W140 M119 cars to the new ignition system.

In general, the advantage is more integration, reliability, fewer parts to change periodically. The distributor is a moving part, and eliminating it removes complexity from the ignition system and a point of failure.

Cheers,
Gerry

[deanyel]

The change was in 96 on the 140 bodies - i.e. that was the start of the 119.980 on the 500 and the 119.981 on the 420. Like a lot of things that got "better" on Mercedes in recent years there's a tradeoff. The parts are more expensive when they go, the wiring harness more complicated and expensive. I don't consider the old caps and rotors such a bad deal - they usually last at least 60k or a little more with reburbishing. And 119 caps and rotors is one of the few things that have actually gone down in price recently - 2 caps and rotors runs about $150 to $175 and they're easy to put in. I'm sure the new way is better but the old way is not really that bad. It sort of a modern versus retro question.

[manny]

suginami

Let me assure you , ALL manufacturers went to DIS ( distributor-less ignition systems ), for EMISSIONS reasons.
When you have to meet long term emissions requirements, worn down points, wobbly distributor shafts ,etc. just didn't cut it anymore.
Also, everytime you eliminate an airgap, or resistance in an ignition circuit,( cap to rotor, rotor to terminals, etc. ) you're winning.

[Tx Benz]

As of 1996, OBD-II regs require the car to "turn off" a misfiring cylinder,
in order to protect the catalytic convertors, and/or environment.

A bad coil(1 per cyl.), bad injector, bad spark plug, or other things will cause the ECU to kill fuel and spark to said cylinder.

[deanyel]

Seems like I read somewhere that later 119 motors had plastic oil tubes, more prone to failure, that earlier 119 motors had better metal tubes. Not an ignition issue, but if true, a point for the earlier cars. Not sure what the break point was.

[stevebfl]

Hi Todd,

Say Hi to Michael for me.

I think you will find that the misfire detection process only shuts down injectors.

Single coils came with the ME engine management system.

[Tx Benz]

Originally Posted by stevebfl

Hi Todd,
Say Hi to Michael for me.
I think you will find that the misfire detection process only shuts down injectors.

Will do,
I bow to superior knowledge.
I'm accustomed to it. Happens a few times a day.

I do catch him on occasion, though.