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You are running the wrong spark plugs. These cars require spark plugs without resistor

The plugs you use now with the standard factory type wires creates a double resistance, which will blow out the brains of the dreaded EZL twice as fast
 

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Discussion Starter #22 (Edited)
You are running the wrong spark plugs. These cars require spark plugs without resistor

The plugs you use now with the standard factory type wires creates a double resistance, which will blow out the brains of the dreaded EZL twice as fast

i got these from Pelican Parts & have used them for quite a long time on both W124 i have, m103 & m104.

Edit: after researching a bit on internet & indeed i have been using the wrong sparkplugs, could any of you post a link where to get the corrects ones?
 

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Exactly what are you turning? the throttle pressure cable? or can you adjust the vacuum modulator?

i already bought a new distributor cap, rotor & rear shield from beru, spark plugs are Bosch FR-8-DC+ & originals spark cables.
Firstly, you appear to have resistor plugs. As said elsewhere, non-resistor plugs are essential and Bosch, Beru and NGK are all fine. Some say that Denso are also OK but I have no experience.

Secondly, yes, you can adjust the vacuum modulator. Under the rubber cap, you will see a thin piece of metal. Gently pull that out a few mms and it will turn.

In simple terms, adjusting the cable changes the point (the ROAD SPEED) at which the up-changes occur. You should aim to align the two little pointers up near the cable adjustment screw, near the throttle body.

Adjusting the vacuum modulator changes HOW the up-changes occur. Turning the adjuster anti-clockwise results on softer, more slurred changes. Turning clockwise results in sharper, harder and quicker changes.

As I said in my previous post, I adjusted the modulator twice to arrive where I am now. I understand that there is a workshop procedure that involves measuring and setting pressures but I do not have the equipment or expertise to do that.

Let us know how you get on.

RayH
 

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Discussion Starter #25
I am not sure if this is the same problem as mine but, we had what I called a "hunting" where the gearbox would try to change up but did not. This would happen from 2 to 3 and from 4 to 5.

The first thing we did was to advance the vacuum modulator - you turn it clockwise - to make the up-shifts harder - we advanced 1 full turn, 360 degrees. I believe that this cured the problem from 2 to 3.

However, 4 to 5 still had the same problem. Two things have happened to cure this problem (I hope - it is difficult to be sure as I need to do 160+ kph to test this):

1. The vacuum modulator has been advanced another half turn, 180 degrees.
2. A leak has been fixed on the Gearbox Solenoid regulating valve A1243040490. This involved replacing a seal but I did not do this job so can comment no further.

I managed to accelerate hard, from a standstill, in Drive, quite aggressively, to about 170 kph. The box changed smoothly and quickly through all gears.

I hope that the problem is finally fixed.

I hope also that this gives you some ideas that may help you.

Also, I do suggest you make sure the ignition and fuel delivery systems are all performing perfectly, using MB only parts or, if that's impossible, Beru or NGK.

My ignition system currently has MB cap, rotor and rear shield, Beru coil, leads and NGK plugs. All is working well.

Good luck to you.

RayH
Just did adjusted the vacuum modulator by 180° clockwise & the problems seems to be solved, on full throttle + kickdown it just goes without hesitation!

Many many thanks
 

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Just did adjusted the vacuum modulator by 180° clockwise & the problems seems to be solved, on full throttle + kickdown it just goes without hesitation!

Many many thanks
Great news.

Did you change those resistor plugs for some non-resistor ones? If so, did it make a difference? - not to the gearbox issue but in general.

It's an unbeatable combination when that M104.980 engine and 722.5 gearbox are working as they should. It makes all the right noises and goes like hell. It also makes you concentrate as that sudden surge at higher revs can catch you out on a greasy road!

Happy motoring.

RayH
 
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