Mysterious 'fixes' by previous owner

[waqas]

Exhibit A:
I recently found clipped wires, presumably belonging to my injection pump starting solenoid. I know they belong to the solenoid because it is missing two wires from it's electrical posts. I know the wires were intentionally clipped because the metal connectors on both sides had clean straight wire-cutter lines on both ends.
This might explain why my car has minor difficulty starting from cold-- it pops like it's running too lean. I plan to reconnect them and see what happens.

Exhibit B:
While replacing some crusty old hoses, I found a metal ball (!) inserted into the hose that feeds air from the air filter, to the screw-regulated inlet at the intake manifold (right by the valve cover). Clearly, this was meant to completely stop air from entering through here, but why not block it off using the screw control?
When I removed and replaced this, my idle increased by about ~200-300 rpms, and was being 'modulated' (oscilating up and down at about 0.5-1Hz, with an amplitude of about +/- 50-80 rpms). I clamped the hose externally, and the rpms dropped down again, but the 'modulation' remained the same, with a slightly decreased amplitude (perhaps 20-30 rpms). The aforementioned air adjustment screw was already screwed-in fully.

Is there a connection between the two here? (and who knows what else I find in future)  Any suggestions on how to proceed?

WAQAS in Austin, Texas

[ja17]

Hello Waqas,

Too high an idle is usually the result of incorrect linkage adjustment.  Check your intake venturi throttle valve. The small slotted screw with 10mm luck nut must be adjusted so as to keep the valve from just sticking closed. It is often times mistakenly used to set engine idle!

You may frist need to disconnect the linkage going to the venturi befroe adjusting. A lot has been posted on this. Check the "engine linkage tour".

Joe Alexander
Blacklick, Ohio

[waqas]

Joe,
Thanks, I'll start with adjusting the linkages (there's certainly a wealth of information here for that). I'll also run some experiments with the solenoid to see if it works (why would someone snip off the wires and leave them hanging there??)

WAQAS in Austin, Texas

[waqas]

By the way, on the inj. pump starter solenoid, which lead is the ground and which is coming from the starter relay? (left/right, etc, I'm assuming there's only one orientation for attaching the solenoid to the inj-pump).

If the inj-pump was already grounded through the engine, why would the solenoid need an additional ground lead?

WAQAS in Austin, Texas

[glennard]

Continuing my theme of 'no two are alike, let alone built alike'.  The Group needs a collection of the 'improvements, fixes, break-thrus, etc that have been wrought on these cars.  Kinda of a companion to the 'idiosyncrasies' originally built in by MB.  The ball in the idle air hose is right up there with a 4 lobe distributor.

[Rolf]

Hello Wagas,

  My car also has 2 leads going to the solenoid. Only one is needed since the solenoid is grounded to the chassis. The brown lead on mine is the ground. I checked the leads out with a multimeter and had someone turn the key, but not start the engine. I found the live wire to the solenoid.

Rolf
1966 230SL Auto
1992 300D
1991 FLHS

[Chad]

Exhibit B makes me laugh... because it sounds like the common DIY modification of the EGR valve on the Mercedes diesels from the w123 chassis (OM617 engines).  A common mod was to put a ball bearing or bb into the vacuum line to the EGR (not legal I think) in order to obtain benefits such as more power and acceleration in these long-lived engines well past 200k miles. Other cheap mods and fixes are commonly used, particularly with the turbos and vacuum line fixes/reroutings. It's interesting to look at these legendary OM617 engines that are used for daily transport. Talk about blowby. Loosen the oil filler cap during idle and some become Mt. Vesuvius. I really enjoyed the OM617.

1967 230SL

[hands_aus]

The engine has to be getting idle air from somewhere so is the WRD closing fully?


Bob Smith (Brisbane,Australia)
RHD,1967 early 250 SL, auto

[Ben]

quote:The engine has to be getting idle air from somewhere so is the WRD closing fully?

.........I agree. With the WRD operating properly, and the car fully warmed up closing the air screw should stall the engine, otherwise there is a vacuum leak !

It took me a while to figure out my car had a porous air pipe from the WRD to the CSV. Everything tested okay 'till eventually I took the hose off and spotted thge deterioration !

Regards,
Ben in Ireland.
'64 230SL 4sp.

[waqas]

Actually, I had a chance to work on it last night, and I discovered the throttle remained slightly open when the accel. pedal was released. It looks like someone had adjusted idle by adjusting the stop screw on the throttle valve (as mentioned in numerous other threads). I had just enough time to change the throttle setting such that it closes fully (but doesn't stick) when the linkage is released. I'll need to do a more thorough linkage check when I have more time. This stalled the car, until I removed the clamp on the idle air hose, and adjusted the idle.

WAQAS in Austin, Texas

[waqas]

Regarding exhibit A, I re-connected the solenoid wires, and the car seems to start a little better when cold. When I have more time, I probably need to make sure the WRD and the solenoid are correctly doing what they're supposed to.

Thanks again for all the help...  My full member dues have been repaid many many many times over!

WAQAS in Austin, Texas