# Cold Start Valve not spraying at all (81' caddy)



## LouisTA (Jun 1, 2010)

Hey all, 

Working on an 81' caddy currently cranking but not starting. I've arrived at the cold start valve, which is not spraying at all. The valve is brand new, thermo time switch has been tested and functioning normally as far as I can tell, and I'm getting between 4 - 5 V at the valve connector when turning the key. Also, there is definitely pressure right up until the valve - just nothing coming out the valve. 

I can't help but wonder if a) there's not enough volts reaching the valve? or b) the valve also needs a certain level of pressure to operate? which it may not be getting?

Any insights would be greatly appreciated! 

Cheers

Lou


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## Butcher (Jan 31, 2001)

The cold start valve is a very simple system. If you power and ground to the valve, it will spray. The thermo time switch does just that [sends power, the valve should be grounded all the time]. So if you do not have 12v to the switch, it will not send 12v to the valve. 

There is only a few seconds that the valve will work. It depends on how cold the engine is.


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## LouisTA (Jun 1, 2010)

Butcher said:


> The cold start valve is a very simple system. If you power and ground to the valve, it will spray. The thermo time switch does just that [sends power, the valve should be grounded all the time]. So if you do not have 12v to the switch, it will not send 12v to the valve.
> 
> There is only a few seconds that the valve will work. It depends on how cold the engine is.


Thanks Butcher, 

So you're saying I should be getting ~12V at the valve? The truck hasn't started in months... how "cold" the engine is has always been a bit of a mystery to me (re: thermo sensor) ... it's in a heated garage but technically it's a 'cold' engine to my understanding. Just working my way through a Hanes book basically and haven't been able to get the expected results when testing the cold-start. Like I said - no spray whatsoever. 

Any recommendations?


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## Butcher (Jan 31, 2001)

Think of the valve like a headlamp. If the light is not working, where would you start. I would start by seeing if there is power and ground to the light. If there is not any power, I would go to the switch. Is there power to the switch? If there is, is there power going out of the switch? If there is, then I would check the wiring. If there is not, then the switch is probably bad.

Same for your valve. The thermo time switch does not work long. The colder it is, the longer it sprays, but certainly would not spray but a few seconds. Once the switch is shut off, I do not believe it will spray much more. It's a feature used to prevent it flooding. Have your test light and I would start testing at the switch and go from there. 

You could always jump the switch to see if the valve opens. Remember, you do not want to operate that valve long because you could flood the engine or worst lock it up.


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## LouisTA (Jun 1, 2010)

Like I said in my first post - there is power getting to the valve (4-5 volts). I may try jumping the switch to see if the valve opens like you say... is faulty cold start enough to stop the truck from turning over?


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## Butcher (Jan 31, 2001)

That's not power, 12v is power. Nothing runs on 5v on that old of a car. 

That's the problem, focus your attention on why it's not 12v


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## LouisTA (Jun 1, 2010)

Ok perfect! That's a big help - I'll try and figure out why only some power is getting to the valve.


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## cuppie (May 4, 2005)

LouisTA said:


> Ok perfect! That's a big help - I'll try and figure out why only some power is getting to the valve.


 Thankfully, it isn't a whole lot of wire involved - the cold-start valve is supplied power via the starter solenoid. 
The larger of the two 'small' posts (at the starter) is 'start' power (from ignition switch); the smaller is 'ignition power during starter operation' (in other words, it's live only when the starter is actually engaged.) 

See if you get +12(ish, probably in the 11s) volts there (out of the starter) during cranking. Go from there.


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