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Mercedes-Benz w126 280s euro; 500sel euro
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Discussion Starter #1 (Edited)
Hi Guys !

Just spoke with my car's prev. owner about my fuel consumption and performance issue and he said that 2 years ago somebody maybe fake mechanic or idk ... tries to "fine tune" the CIS from this EHA valve!!!(i read some topics after this that is strongly not recomended action to do) So it seems that i've never know what is good adjusted CIS system So my question is does somebody knows the original(default/oem factory) adjustment/setting of the screw at the EHA valve body? So that should be the first point to start from...i searched the forum and found less about the original setting only for the "magic 1/4 turn" and someone says that the OEM adjustment is 6 and 1/5 or 5 and 3/4 turns but for me that seems impossible because mine now is 3 and 1/4 turns CCW from bottom .
The car is 86's 500sel M117.965 ECE

Thx in advance
 

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Premium Member
560SEC, 190E, Frontier, 240Z
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1,329 Posts
The settings on the EHA valve have to be fine-tuned for each car and Distributor.
It sets the difference in fuel pressure between upper and lower chambers.
As a rough, you could use fuel pressure gauges and get the pressure difference referenced in the manual.

Or, you can reference the Duty Cycle and see what the DC does at 2500rpm compared to idle. The DC needs to be very similar at 2500rpm vs idle and then your EHA is about right.

Remember to burp the FD each time you open the system and drive it some to normalize the changes in between.
 

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Registered
Mercedes-Benz w126 280s euro; 500sel euro
Joined
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45 Posts
Discussion Starter #3
The settings on the EHA valve have to be fine-tuned for each car and Distributor.
It sets the difference in fuel pressure between upper and lower chambers.
As a rough, you could use fuel pressure gauges and get the pressure difference referenced in the manual.

Or, you can reference the Duty Cycle and see what the DC does at 2500rpm compared to idle. The DC needs to be very similar at 2500rpm vs idle and then your EHA is about right.

Remember to burp the FD each time you open the system and drive it some to normalize the changes in between.
Yep...i mean instead to purchase new EHA with the default setting to adjust this one by myself...
so...
-i know that the delta-P btw upper and lower should be 0.4bar??(didn't check it yet)
-about Duty cylce on idle ~600rpm is 6.83V and ~2.500rpm is 6.85V ( new...spark plugs ,cables,overhauled FD,fuel accu,pumps,fuel return,vlv,filterS,relays)
 

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Outstanding Contributor
600 (3.200 mm)
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1,542 Posts
So that should be the first point to start from...i searched the forum and found less about the original setting
N.B. Adjustment of the KE-Jetronic, and in particular EHA - is very difficult process. Which demands the attentiveness and the presence of the certain knowledges. :)

Original setting (on new EHA):
depth from EHA body to adjusting screw is 6.6 mm

Current at actuator (only ECE/RÜF):
ignition "ON" = + 70 mA
idle, coolant temp. +20 C = 2.6 mA
idle, coolant temp. +80 C = 3-4 mA
post-start enrichment, +20 C coolant temp. = 7-13 mA
acceleration enrichment at +20 C and blipping throttle = >20 mA
full load enrichment at approx 5000 rpm = 4-6 mA
part load mixture adaptation = from -9 to 0 mA
decel fuel cutoff = approx -60 mA


Salut!
 

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1989 560SEC
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Outstanding Contributor
600 (3.200 mm)
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1,542 Posts
But we should remember necessarily, that adjustment of work of the KE-Jetronic must be carried out only as adjusting of a whole system, including each component.
Therefore as, each separately taken component defines work of all system.

Salutte! :)
 
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