can anyone tell me how to test a cold start valve and thermo time switch on a 73 450sl?
- posted
17 years ago
can anyone tell me how to test a cold start valve and thermo time switch on a 73 450sl?
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
(this test does not include the function of the TTS)
Below 35 C Cooling Water Temp
The control period increases with decreasing temperature by approx. 1 sec. per 5 C.
+35 C = 0 sec +20 C = 3 secThe 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
PS What's your engine doing or not doing? 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.
Disconnect the cold start valve when engine is hot... see if it makes a difference.
There is no difference when I unplug the cold start.
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.
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?
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.
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