I just put in a 91 engine into my 88 190e. I was trying to find how to check and if needed adjust the timing. But from what I can find, the timing is not adjustable on my vehicle.

Can anyone confirm this?

And if this is the case, how is the timing controlled? By computer i suppose?

Thanks,

Josh

Josh, check out this thread:

300E Ignition Timing

About 10 posts in they actually get around to explaining how it works.

To answer your question, yes, the timing is controlled by the engine control computer depending on rpm and engine load. There is a way apparently, to gain an additional 6 degrees of advance, in 2 degree increments, by changing out a resistor, but I'm not positive it applies to your car. See this thread:

READ!!! Free HP for W201 & W124 owners! (Pictures!)


Hope this helps,

Gary

Great information Gary, thanks.

So would I be wrong to say that:

Loosening the bolt at my distributor and turning it to the maximum in either direction will have no effect on the engine?

And I shouldnt need to worry about timing because the computer has set my new engines timing automatically?


Many thanks,

Josh

Are you talking about a four of six-cylinder engine? The six-cylinder is not adjustable. The EZL module controls timing using the TDC sensor on the front balancer and manifold vacuum as inputs.

My erstwhile '84 four cylinder 190E had a conventional electronic distributor, and the timing could be changed by rotating it, but I don't know if the later four-cylinders had this setup or a system similar to the sixes.

The distributor at the front of the head on a six just distributes the secondary voltage. It cannot be used to change the timing.

In the last six months there have been discussions of changing the timing by changing a resistor. You'll have to search for it. Changing the resistor apparently changes the rate that timing is changed, but not initial timing and is used to "tune" the timing map to different fuel octane ratings.

Duke

I have seen the discussion in reference to the resistors. Mine is an 190e 1988 2.3 8v. When I move the distributor nothing changes, at least nothing which i can notice.

Yeah, you can probably get it to mis-fire by turning the distributor all the way one way or the other so that the spark won't jump to the terminal in the cap, but the distributor doesn't regulate the timing.

The EZL ignition reads crank position, then calculates the delay for the next spark and fires the coil and the appropriate time. Distributor just sends the spark to the correct plug.

On the M103, the distributor doesn't move.

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!