Temp sending unit on a 70?

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Sep 9, 2005 | 07:25 PM

70inSBIn

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From: Mishawaka Indiana

Temp sending unit on a 70?

Ok, maybe this is a dummy question, but I was changing the plugs in my car, and noticed a sensor of some kind screwed into the passenger side head. Looks to be some sort of temp sending unit but its not hooked to anything, and I dont see any terminal for it anywhere. Besides that, what would it go to? I saw a replacement for it in Corvette Central, but its just called a "temp. sender in cylinder head".

I cant figure out what it would be for, even if it was hooked up. Did they have a different set up for coolant temp? Mine is hooked up on the driver side for that. Did they have solid state sending unit for oil pressure, and my mechanical tube is actually incorrect? The gage inside looks orginal. Im puzzled about it, but I obviously dont need it, as the car runs great and all the gauges work fine.

Sep 9, 2005 | 07:51 PM

marshrat99

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From: Dayton Oh

On my 79, there is a temp sending unit on the passenger side that controls the aux. electric radiator fan. The regular one attached to the temp guage is on the driver side.

Sep 9, 2005 | 08:33 PM

gearheadz

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From: Gainesville, Florida

The passenger head sensor is for the TCS (Transmission Controlled Spark) system. It's an emission system component in a system that disabled vacuum advance when the tranny was in 4th gear & engine had reached a preset temp.

As you already know, you don't need it. I would guess 90%+ of TCS equipped cars don't have it working or even have it hooked up.

Sep 9, 2005 | 08:38 PM

stingry

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From: Canberra AUSTRALIA

St. Jude Donor '05-'06

Quote:

Originally Posted by gearheadz

Further to what Gearheadz said. Check your QJET for the correct vaccum hose routing. If it passes though the TCS soleniod on the way to the distributor then you may be killing your advance right now if it the TCS sensor is not hooked up anyway. Run a vac line straight from the carb to the distributor and see if you notice an improvement. It is probably bypassed already.

I do have all my wiring/solinoid/sensor and vaccum intact, but bypassed for now.

Sep 9, 2005 | 10:02 PM

81coupeowner

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From: denton tx

Can you use that tsc sensor to run the aux fan?

Sep 10, 2005 | 12:50 AM

70inSBIn

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From: Mishawaka Indiana

Thanks guys. Thats informative. Actually there is just a straight hose from the carb to the advance unit. I thought that was normal. Hmm. Was this on all 70's, or was it a California item?

Sep 10, 2005 | 02:17 AM

Carl Granquist

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From: Shoreline WA

Quote:

Originally Posted by 70inSBIn

Thanks guys. Thats informative. Actually there is just a straight hose from the carb to the advance unit. I thought that was normal. Hmm. Was this on all 70's, or was it a California item?

Don't think it was a California thing cuz mine's been disconnected for years now and it's a western Washington car. Maybe something owners back then did. I thought the TCS thing started in '71? Anyway, I've wondered whether taking it out of the system changes how you adjust the timing? I'm trying to line up a Lars tune-up soon.