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M110/W126 pneumatic/vacuum hoses on fuel system

Hi all,

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 good.

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

Phil Cape Town South Africa

Reply to
Phil
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I know about W140 (S-series 1991-1998) but not W126, so any attemt to help may be misleading.

But for $25/year you can subscribe to Alldata

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where you among a lot of other usefull technical information also can find the required vacuum diagrams. It can save you a lot of frustrating hours of work.

Jens Denmark

Reply to
Jens

Doesn't your 126 have KE jetronic?

Reply to
CaptainW116

I don't think so but how would one tell them apart visually?

-Phil

Reply to
Phil

Rather than it having a control pressure regulator it has a system pressure regulator.Also on the back of the fuel distributor located on the airflow sensor is an electrohydraulic actuator(electrical connections)with "BOSCH" stamped on it ,whereas K jet has none but for a fuel pump shut off switch located at the top of airflow sensor.

Also inside of a KE jet airflow sensor is a potentiometer which sends a variable voltage to the ECU. If you have an ECU then it is KE .

K jet is also known as CIS KE jet is also known as CIS-E

Hope this helps.

Reply to
CaptainW116

Thanks for the info. Mine is definitely the K and not KE since there are no electrical connections on the fuel distributor or the airflow sensor body.

-Phil

Reply to
Phil

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