I have a 1985 280SE W126 (European) which has done 300 000+ km and was
"worked on" by previous owners. I have been trying to correctly connect up
all the thin hard plastic air/vacuum hoses connecting various parts of the
fuel injection system etc.
So far, I have not been able to reconcile what I see in the K-Jetronic
diagrams with what exists in the engine compartment of the car.
So far I have:
*Inlet manifold vacuum with cross-shaped rubber 4-way divider connected to:
-distributor vacuum retard.
-frontmost electric solenoid valve for A/C fast idle ??
-other electric solenoid valve to vacuum-operated valve on thick hose just
below air filter ( -- what does this do and when?)
*Connections just above and below the throttle-valve (butterfly): Where do
these go? The book says auxiliary air device but I have nothing that looks
like the one in the diagram. Currently just connected together.
*On exhaust manifold a vacuum operated valve connected to a pneumatic
temperature switch on the cyl. head connected to ???
*On inlet manifold, nearest firewall, the rubber hose to warm-up regulator
(which I just replaced at significant cost)
*There is a second connection on the other side of the vacuum retard unit on
the distributor. Is this just a breather or must it be connected somewhere?
Not all 280SE's have this.
*A pipe connected to another gizmo located under the inlet manifold.
Function unknown. Seems to have no effect on engine speed with vacuum or
pressure applied with engine running warm or cold.
I have checked the hose clamps and integrity of all the 1/2" dia pipes under
the inlet manifold and to the idle air adjustment, etc.
I have replaced the rubber bellows between the air flow sensor body and the
manifold, the fuel filter is new and the fuel pump and accumulator are
Currently she always starts first turn of the key hot or cold, but cold
idling starts at about 1400 rpm going to about 1000 rpm during the first
minute, and is about 800-700 rpm through warm to hot. Idle is a bit uneven
but acceleration is smooth with no hesitation.
I am hoping that fuel consumption will improve from the previous
18-20l/100km with the new warm-up regulator installed.
Any advice or pointers greatly appreciated