cold start valve

can anyone tell me how to test a cold start valve and thermo time switch on a 73 450sl?

Reply to
450sl
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got out the old shop manual and here's what they say about the TTS. (I've had my SL since 75 and just brought it back to life after sittin' in my garage for nearly 8 years)

Above 35 C cooling Water Temp

  1. connect voltmeter to connection of starting valve
  2. Connect terminal W (cable colour pink) of TTS to ground (switch housing)
  3. Actuate starter. The voltmeter should then indicate approx. 10V.

(this test does not include the function of the TTS)

Below 35 C Cooling Water Temp

  1. Connect voltmetwer to connectuion of starting valve
  2. Actuate started. After a given period the voltmeter should indicate
10 V (depending on cooling water temperature)

The control period increases with decreasing temperature by approx. 1 sec. per 5 C.

+35 C = 0 sec +20 C = 3 sec

The TTS is checked with an ohmmeter

Test values above 35 C Connection W-ground = approx.100 ohm Connection G-ground = approx. 60 ohm ConnectionG-W = approx. 40 ohm

Test values below 35C Connection G-ground = approx. 20 ohm ConnectionW-ground = approx. 0 ohm (contacts in switch closed)

Then here's my thought----pull the cold start valve off and see it's shootin' out gas when you're starting the engine

OR---------e-mail me your real address, I'll make a photocopy of the two pages with photo's and diagram, and send them to you, if you like..Ken

Reply to
Ken

PS What's your engine doing or not doing? Ken

Reply to
Ken

Hey Ken I appriciate the input. My car will run fine untill the temp gage hits about 180 where it stays, then it will start missing bad and smells of fuel. it never dies, but runs very rough.

Reply to
450sl

Disconnect the cold start valve when engine is hot... see if it makes a difference.

Reply to
Tiger

There is no difference when I unplug the cold start.

Reply to
450sl

Then I would suspect warm up regulator.

In this case, I would also check the spark plug wires too... check the resistance... check the distributor cap and rotor... make sure they are clean and no crack.

I forget that this car use point system for the ignition... you need to double check the points that there is no oil.... everything is good there.

Reply to
Tiger

thanks for your help Ken. if I unplug the cold start plug it still runs bad , if I unplug the thermo time plug it dies, does this mean anything?

Reply to
450sl

Hey tiger, when i unplug the cold start it still runs bad, pull off the thermo time plug it dies does this say anything? I put new plugs, condenser, rotor, cap, wires coil, and still have same problem.

Reply to
450sl

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