Mercedes Benz 280CE 1974mod M110 Bosch D-Jetronic

Hi,
I try to fix a Mercedes Benz 280ce 1974mod with M110 engine and Bosch D-Jetronic that not run so good, I try to go true everything to see if I can find the problem.

Now i have come to the ignition system, is here someone that know what ignition timing, dwell, ignition breaker gap and sparkplug gap that it shall be on this engine? It have transistor ignition.

I now use ngk bp6es with 0,8mm gap, ignition timing 10° btdc with vacuum disconected, dwell 32° on idle with 0,3mm gap on ignition breaker, but i dont know if this is correct?

Mvh. Knut Åge

Hi Knut Åge,

[strike]you will find ignition timing for you engine above in 107 workshop manual as it is the same engine M110.[/strike] Sorry, I forgot that M110 D-Jetronic is not there.

Okay here is the data for M110 Europe version:

• Dwell 34-40° in idle, not changing more than 3° in other rpm
• idle-run with vacuum: TDC +/- 2°
• 1500/min without vacuum: 14 - 19°
• 3000/min without vacuum: 32°
• vaccum retard in idle-run: 8-12°

Thank you, you know what can be wrong if dwell angel going down more than 3° on higher rpm? This going down to ca. 25° on higher rpm.

And you know the spark plug gap? Is 0,8mm ok?

Mvh. Knut Åge

Hi,

sounds like your bushings are worn and shaft dances a bit or the spring that closes contact is worn out. I always use 0.7 mm gap an my car's spark plugs.

Hi Knut,
try to adjust the points to the correct value first and clean (polish) the contact plates of the points.
Dirty contacts can lead to changes in the dwell values, too.

Just to make sure the bushings are really worn.

Regards
Norbert

Hi,

Have now checked more and see that the shaft in the distributer can move litle and I dont know if trancistor ignition box is in good condition, so we now order a new 123 ignition distributer and New red Bosch coil and see if things will be better. I have good experience with 123 ignition distributer on Volvo 164E with D-Jetronic.

Thank you both for help

Mvh. Knut Åge

Hi Knut Åge,

if you have a scope measure how often and how long the 123 ignition trigger contacts close during a rotation of distributor. You might be surprised.

I am not a big fan of 123 ignition. I would recommend to get your old distributor reconditioned.

Hi,

I dont have scoop, can this be something that i can use to scoop trigger contact and injectors?
www.ebay.com/itm/292521108898

You have bad experience with 123ignition distributer? what problem it can /will make?

Mvh. Knut Åge

Hi Knut Åge,

you could but that is not worth it. I have done that once on a Volvo 123 ignition distributor and did not find 150° closure but 2 x 90° closure on both contacts. 123 could not explain to me why they did it like that. Now this works as ECU filters out a contacts double closure. But if there is any noise on one of the lines it would end in desaster as ECU might suddenly recognize double rpm.

I have now find the problem with this car, it was å defekt androidcell in map sensor, so it going too lean.
The Bosch nr. Was correct 0 280 100 111, it have not be open or adjusted. With a new used knowing working map sensor, the engine is now running Nice again.
Mvh. Knut Åge

Hi Knut Åge,

really a broken Aneroid cell? In a type 3 MAP sensor? Well I have seen them go off linear but never a broken one so far. Are you sure it was not just detuned?

I have not open it yet, so can not be 100% that one of the androidcell is broken.

But I have see this 2times on type 2map sensor and than think the same can happend with type 3map sensor? The car have working fine before with this map sensor, it have not be open or adjusted. Have you other teori on what can detuned the map sensor?

My teori is if it is hole in one of the androidcells than that androidcell will expand and make the map sensor detuned so the a/f mixture will be too lean, what you think about that teori?

Mvh. Knut Åge

Hi,

I do not believe in your theory.

A type 3 only has 1 aneroid cell and I personally have not seen any of them with a crack.

Type 3 androidcells is not dobble as on type2 androidcells? You have picture of a type 3 androidcells ?

Mvh. Knut Åge

Hi,

that is what you find in chapter 4. Type 3 has an aneroid and a differential pressure cell with ventilation.

I see now the picture of the type 3androidcells and I see this also have to chamber in the androidcells same as with type 2 androidcells, so it is posible to have hol in one of the chamber in the androidcell, than it will go too lean. You not understand that teori?

Mvh. Knut Åge

Hi,
some Opel guys had the problems the Type 3 MPS was clogged with oil and mud and did not function properly.

Some managed to bring it back to function without taking it apart by rinsing it several times using a fluid (maybe just fuel, maybe another kind of solvent).

Regards
Norbert

Hi Norbert,

but that is a specialty of Opel MAP sensors, no matter whether type 2 or type 3. It happens as the oil moisture trap fails on that engine. Have never seen that on Mercedes-Benz cars. Cleaning and rinsing will by the way not work if you have a flutter valve inside.

Drdyse wrote: I see now the picture of the type 3androidcells and I see this also have to chamber in the androidcells same as with type 2 androidcells, so it is posible to have hol in one of the chamber in the androidcell, than it will go too lean. You not understand that teori?

Mvh. Knut Åge

No I do not understand your theory. If the single aneroid cell would leak, it would loose vacuum and thus expand on full-load - not letting mixture enrich there. In idle-run it should not matter much.

Hi,

If the single androidcell would leak, it will have same pressure on inside as on outside of the leaking androidcell and it will expand, same as it will do at low load/ high vacuum/ low inductance, you agree?

+ with only one working androidcell it will have half of change in inductance from 0 Inhg to 25 Inhg vs. with 2 working androidcells.

so with one defekt androidcell, it will go too lean on every load, it will also do that the idle mixture will be too lean, you will not have posiblety to rich the idle mixture to the correct CO value and the inlet vacuum will be lower too with this very lean mixture.

You now understand the teory? or you have a better answer on what have detuned a map sensor that is not open or adjusted?

mvh. Knut Åge

Hi nordfisch,

I will see when I open up the defect MPS if it is clogged with oil and mud, but I have not see before that it have be so much oil and mud in the MPS that it have effect on function on the MPS, but I have most experianse with type 2 MPS to Volvos and there I only have see small amont of oil and mud inside the MPS.

When I come home next time from work, I will open it and check the androidcell from the defekt/detunded 0 280 100 111 and compere to a knowing working type 3 androidcell I have, I can check det high on both in atmosferic pressure and I can put it on a emty clean jam jars and pump up vacuum on the jam jars and see how much it expand, to see if it is differance as I expecting, than it will confirm or break my theory... time will show and I will show the result here

mvh. Knut Åge