Engine Wiring

[Mark in KS]

Yesterday was a beautiful day in Kansas City. While giving the 230SL a good airing out, I managed to blow a water line and had to do a little field replacement. The high pressure line between the water block and the thermostat blew.

After replacing the water line, the old one had two wires tie-wrapped to it. These wires come across from the left fender apron along with the two wires that go to the time switch. Does any body know what these could be? The extra wires are wrapped in the same harness as they come across into the engine bay.

1967 230SL

[ja17]

Hello Mark,
Can you be a little more specific about which water hose it was and where these wires terminate?  I am not sure what you mean by "water block".

Joe Alexander
Blacklick, Ohio

[Mark in KS]

This is the water block that is between the FI pump and the engine block on the left side.

[ja17]

Hello Mark,
A lot of engine electrical varied depending on the year and equipment( auto trans etc.).  Some electrical parts on that side or the engine were: Engine coolant sensor (thermostat housing)one wire, switch for the three position solenoid on the transmission (intake venturi)two wires, idle increase solenoid (intake manifold linkage)two wires and the cold start device on the intake manifold, one wire. Your car may have all or some of these devices depending on year and equipment.
Are these two wires connected to anything? If you can see the colors of the wires I can look up the color on my wiring diagram.  
What year is your car and does it have an automatic transmission?

Joe Alexander
Blacklick, Ohio

[Mark in KS]

Joe, thanks for your reply.  My Pagoda is a 1967 230SL.  Built in August of 1966.  It's a manual, 4-speed.  The two "extra" wires are a brown one and a black one with a pink? stripe.  Here's a photo:

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[ja17]

Hello Mark, this is a great photo. It should be kept in the site archives. It shows the metal oil lubrication line next to the block, so we need to assume at least some 230-SL injection pumps had this feature. It also shows some nice original hose clamps and hoses. It looks like an original spark plug wire set is still in use and some of the original gold cadnium plating is still visable. Most important those wires which are not connected probably were originally connected to the starting magnet on the back of the injection pump. If your pump does not have this magnet it probably has been replaced at one time or another? These wires if as described pass through a relay which is influenced by the time switch and the thermo sensor for these. Engines from August 1965 up to 1970 had this injection pump "starting solenoid". According to a factory workshop suppliment, this unit activated during the starting cycle at all temperatures. Now depending on weather your injection pump has been replaced and depending on which starting valve is on the intake, you may not require this to be in use anymore? Hope this helps.


Joe Alexander
Blacklick, Ohio

[Mark in KS]

Hi Joe,

Amazing!  You're saying that my FI is not all wired up.  Since the car is on jacks, I crawled underneath and took an underside photo of the back of the FI pump.  I note that the terminals have NO screws in them!  Also, a photo of the serial number, if it helps determine the age of the unit.  A third photo shows the right side of the engine bay to illustrated the manifold valve.  It pays to have a nice Nikon 950 handy.  Please comment on the images and see if you still agree with your observation.  The engine runs quite smooth.

Mark in KS

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[ja17]

Hello Mark,
That solenoid is a starting aid and may have been disconnected for a reason, if the system was malfunctioning. If your engine starts ok, I would not worry too much about it. The later engines used an injection pump without this solenoid, however the cold start device on the intake was different. Maybe yours has been upgraded. There were some different versions of this starting circuit. If you think your engine is not starting correctly you may want to try hooking it up to see if it helps. It appears that your (R11) pump is correct.
 Cees, these are really nice close-up photos Mark has taken these should be filed for refference.
The first photo shows the starting solenoid on the injection pump. It also gives a clear view of the injection mixture adjustment knob. This adjusts the injection fuel mixture from idle up to 1700rpms. Also is visable is the oil dip stick (slotted bolt).
Photo two; shows the intake manifold with the sarting device. Some nice original details seen here also.
Photo three; the serial plate on the injection pump showing the correct R11 pump. Good Luck. Thanks for the visuals!


Joe Alexander
Blacklick, Ohio

[Cees Klumper]

I posted the photos to the photo gallery together with Joe's comments. We can file more photos in this particular topic, which I labelled "engine bay pictures". We can also start additional topics, for other technical photos, by subject (e.g. "rear axle photos", "suspension and brake photos" etc.

Cees
white 1969 280 SL