Pagoda SL Group

W113 Pagoda SL Group => Drive train, fuel, suspension, steering & brakes => Topic started by: pauldridge on November 04, 2007, 19:38:51

Title: Cold start solenoid
Post by: pauldridge on November 04, 2007, 19:38:51

My recently acquired 230SL has a 280SE engine...Among the many defects I inherited from the PO was a discovery that the cold start solenoid is not hooked up at all.  Additionally, the PO had bypassed the wiring to the starting injector (on the intake manifold) in favor of a cockpit switch.  I have found this works quite well for starting.. just hit the switch for a second or so, hold your mouth just right, and the old bird cranks right up.  After a short warm up, the engine runs nice and smooth, WITHOUT help from the cold start solenoid on the IP.

My question... does that cold start solenoid perform any other function than assisting with cold running?  Reason I ask is that I am also experiencing consistent pinging under load, and wondering if that solenoid might have any effect on mixture control for normal operations?

230SL, 59 Jag MK IX, 65 Stingray Roadster, 89 Carrera Cabriolet

Title: Re: Cold start solenoid
Post by: hands_aus on November 05, 2007, 05:06:44

If the CSV (inlet manifold) leaks the additional fuel will adversely affect the air/fuel mixture.
Have you checked things like timing, worn points (if used), condition of distributor for the problem of pinging.
The usual reasons the CSV doesn't work is the relay contacts are not completeing the circuit or the thermo time switch is not working properly.
Some people swear by the hot wire method for a cold start.
I installed one when I first bought my car in 2002 and left it there when I installed a time switch and harness.

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

Title: Re: Cold start solenoid
Post by: bpossel on November 05, 2007, 12:22:26

I had a cold start issue and it ended up being a defective relay.  The relay was new, but Joe determined it was defective during this summers PUB.  It was hard to believe that a "new" unit would be bad, but it was!  Sometimes it's a simple fix....  if you know where to look!
Bob

bpossel  (Memphis, TN.)
'71 280SL  /  '97 E320

Title: Re: Cold start solenoid
Post by: ja17 on November 05, 2007, 21:06:13

The cold start valve performs no other function other than being a starting aid.
 Make sure you are using high octane fuel and your timing is correct to prevent pinging. These days 92 to 94 octane seems to be what is available. Even with this octane you may have to set the timing back a few degrees to prevent pinging.

Joe Alexander
Blacklick, Ohio