Author Topic: What is this  (Read 2170 times)

Offline bnoggle

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What is this
« on: May 27, 2017, 03:38:31 PM »
Can anyone tell me what this sensor is on the passenger side of a 1983 chevy 250 head. It is located between the third and fourth spark plugs with one vacuum line attachment.


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Offline Irish_Alley

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Re: What is this
« Reply #1 on: May 27, 2017, 04:51:44 PM »

im lost. i was going to say someone just plugged the coolant temp sensor port. but the single vacuum line has me. i would think if it was some sort of vacuum switch like what goes on the thermostat housing there would be two lines. one for constant vacuum and one for the switch side

but where do the vacuum lines go to?
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When you have eliminated the impossible, whatever remains, however improbable, must be the truth ~Sherlock Holmes

Offline bnoggle

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Re: What is this
« Reply #2 on: May 27, 2017, 06:04:28 PM »

im lost. i was going to say someone just plugged the coolant temp sensor port. but the single vacuum line has me. i would think if it was some sort of vacuum switch like what goes on the thermostat housing there would be two lines. one for constant vacuum and one for the switch side

but where do the vacuum lines go to?
The vaccum lines go to a coolant temp sensor port which connects it to the vaccum advance, carburetor, and intake manifold. I think it is similar to a coolant temp sensor and that there is an internal vaccum tube in the head of the engine that also connects to the intake manifold. The engine has the integral head so there is no way to easily tell. 


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Offline Irish_Alley

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Re: What is this
« Reply #3 on: May 27, 2017, 06:13:34 PM »
sorry i was thinking this was a SBC. just noticed it was a 250. i have no idea about them, i still dont understand how they pull vacuum off the head. i would think they would went to the intake for that
If you can’t tell yourself the truth, who can you tell it to?~Irish_Alley

When you have eliminated the impossible, whatever remains, however improbable, must be the truth ~Sherlock Holmes