Author Topic: Temperature Gauge Sensor Location(s)  (Read 340 times)

P-Js_BLKBRRD

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Temperature Gauge Sensor Location(s)
« on: April 11, 2019, 06:42:13 PM »
I'm installing a FI-Tech TB EFI setup on "BLKBRRD" and it includes a new temperature sending unit.  According to the tech person I talked with if I want the temp gauge in the instrument cluster to keep working I need to find another place to install their sending unit.  I've looked around a little bit and haven't found an extra spot (yet) where I can install it.  I've found the stock sending unit near the front of the driver's side head.  On the passenger side head near the back there is something installed there (with vacuum type hoses attached to it).  I'll need to loosen the A/C compressor to get a better look at that side.

"BLKBRRD" is a '78 with the 400ci w/AC.  Any other spots where I could fit a suitable place to install the new sending unit?

Thanks!
"BLKBRRD" & "Friends"


'78 Trans Am w/Pontiac 400, 4 spd, Hurst T-tops

Gene-73

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Re: Temperature Gauge Sensor Location(s)
« Reply #1 on: April 11, 2019, 07:34:15 PM »
Also check your intake manifold for an open spot, there's usually a couple there in the front.  If every available opening is being used, you might be able to get a thermostat housing with a temp sensor port.

Something like this https://www.summitracing.com/parts/fss-84842/overview/make/pontiac
Gene


oldskool

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Re: Temperature Gauge Sensor Location(s)
« Reply #2 on: April 11, 2019, 08:29:46 PM »
Mine's in the PS head. But, it's race only, with no A/C. I have put 'em in the intake water crossover, in the past.

P-Js_BLKBRRD

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Re: Temperature Gauge Sensor Location(s)
« Reply #3 on: April 11, 2019, 11:14:27 PM »
Thanks for the replies guys!  I'll be looking more ports over the weekend but have noticed there are a couple of things already plugged into the intake near the thermostat housing. 

Gene-73 - thanks for the link to the housing with the threaded port.  That looks like a good alternative.  Wonder how accurate a reading would be tho' until the thermostat opens up.  Guess I could put the gauge sending unit in there and the TB EFI sending unit in the head port.

"BLKBRRD" & "Friends"


'78 Trans Am w/Pontiac 400, 4 spd, Hurst T-tops

cyber104

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Re: Temperature Gauge Sensor Location(s)
« Reply #4 on: April 12, 2019, 11:56:48 AM »
Same car as you have...............

Does this help?

Electrical...........


Mechanical..........
1978 TA 4-Speed W72

Re: Temperature Gauge Sensor Location(s)
« Reply #4 on: April 12, 2019, 11:56:48 AM »

djustice

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Re: Temperature Gauge Sensor Location(s)
« Reply #5 on: April 12, 2019, 12:30:06 PM »
Is the sensor placed in Passanger Sside head a 3/8" or 1/2" ?
1973 Firebird formula 400 W/YC code 455 (73 casting)
6x-8 heads, 140 lb spring preassure closed, scorpion 1.5 Roller rockers, holley sniper efi, edelbrock performer inntake, Headman 28150 headers 1 3/4" primary, Pypes SGF11R exhaust, cam unknown, alu radiator w/twin 12" fans. Yukon duragrip posi w/3.42 gears.

P-Js_BLKBRRD

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Re: Temperature Gauge Sensor Location(s)
« Reply #6 on: April 12, 2019, 11:56:00 PM »
Same car as you have...............

Does this help?

Electrical...........
(photo removed)

Mechanical..........
(photo removed)



Sort of - the sending unit in the head looks to be the same but what is in the port next to the thermostat housing is different.  Wasn't in the garage today but I'll take some photos over the weekend to show what is in the ports currently.  I need to dig into some manuals to try and figure out how much of the emissions stuff is really needed now that the Q-jet will be out of the picture.  SO MANY vacuum lines going all over the place...!!!    :shock:

THANKS...!!!
"BLKBRRD" & "Friends"


'78 Trans Am w/Pontiac 400, 4 spd, Hurst T-tops

P-Js_BLKBRRD

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Re: Temperature Gauge Sensor Location(s)
« Reply #7 on: April 12, 2019, 11:57:31 PM »
Is the sensor placed in Passanger Sside head a 3/8" or 1/2" ?


Offhand I don't know.  If I end up pulling it out for any reason I'll measure it.
"BLKBRRD" & "Friends"


'78 Trans Am w/Pontiac 400, 4 spd, Hurst T-tops

cyber104

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Re: Temperature Gauge Sensor Location(s)
« Reply #8 on: April 13, 2019, 07:27:15 AM »
Where I have installed my manual gauge sender you probably have a thermo-switch with a bunch of vacuum lines connected to it.

When I rebuilt my car I removed all of the emissions - right or wrong - and that port was available
1978 TA 4-Speed W72

P-Js_BLKBRRD

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Re: Temperature Gauge Sensor Location(s)
« Reply #9 on: April 13, 2019, 10:26:11 AM »
Where I have installed my manual gauge sender you probably have a thermo-switch with a bunch of vacuum lines connected to it.

When I rebuilt my car I removed all of the emissions - right or wrong - and that port was available

Yes - there are several vacuum lines coming out of it.  And on the passenger side head there is a similar kind of unit with vacuum lines scattering about.  I'm guessing the TB EFI will make the car run cleaner so I could probably get away with removing some or all of the emission stuff as well.  Don't live in an area with required emissions testing so...

Thanks again - you've been a GREAT help...!!!
"BLKBRRD" & "Friends"


'78 Trans Am w/Pontiac 400, 4 spd, Hurst T-tops

MNBob

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Re: Temperature Gauge Sensor Location(s)
« Reply #10 on: April 17, 2019, 02:25:04 PM »
Quote
I'm guessing the TB EFI will make the car run cleaner so I could probably get away with removing some or all of the
emission stuff as well.


I would think it would be an order of magnitude cleaner.  GM did a great job with the QJet with idle circuits, transition circuits, choke, choke pull-offs, metering jets, etc.  But an EFI is a computer measuring all kinds of inputs and optimizing the A/F ratio for all those conditions.  While it does depend on a program or map, it also includes a feedback loop with the O2 sensor to constantly adjust.

I would think almost all of the vacuum lines could be removed.  The EFI has ported vacuum, manifold vacuum, and power brake vacuum included.  I read over on PY that some keep their charcoal canister and use it for the tank vent.

Is it possible two hook two wires (gauge and EFI) to the existing sensor?  I have found by hooking up temperature switches in intake water crossover next to the thermostat, that the temperature there is like 15 degrees higher than in the head as measured by the gauge.  Of course who knows how accurate these switches are, or the gauge for that matter.
1979 TATA Extreme TKO .64
Hedman elite; Pypes 2.5; Borla XS; MSD 6A; Edelbrock intake; open scoop; modified Q-jet; Powermaster 150; 4 core radiator/Mark VIII fan; RobbMc mini starter; subframe connectors; solid body mounts; fiberglass rear springs; poly sway bar and link bushings; 81 master; D52’s; Blazer disks; 225/60 & 235/60 17's TrueContact's; relays for PW, PDL, lights; keyless entry

P-Js_BLKBRRD

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Re: Temperature Gauge Sensor Location(s)
« Reply #11 on: April 17, 2019, 05:13:33 PM »
Thanks MNBob,

Looking through manuals I have it seems that a majority of the vacuum lines are related to the EFE and EGR systems.  Thermal vacuum switches for those two systems occupy two water ports - one in the intake manifold next to the thermostat housing and one in the passenger side head.  If those two systems aren't needed that solves my problem as I could then use either of those two ports for the new temperature sending unit (as cyber104 noted).  The FI-Tech tech rep said their sending unit had to be separate from the temperature gauge sending unit - no splicing of wires allowed!.

The FI-Tech tech rep also said that the charcoal canister can be pulled.  Since I'm using their Fuel Command Center to feed the throttle body of the four lines attached to the charcoal canister the only line needed is the fuel tank vent which connects to the FCC.  The other three lines go directly to the Q-Jet so with it out of the loop those lines go away.

I have noticed that the temperature gauge seems to run high (the sending unit is in the drivers side head).  Using an infra-red scanner the temp readings on the thermostat housing, the radiator hose and the top of the radiator are usually within a couple of degrees of each other and are consistently lower than what the gauge reads - which is just the opposite of what you have noted.  Ah, the mysteries...!!!   :lol:


*** UPDATE ***
Was finally able to talk with a mechanic friend from California who has been wrenching for 50 years.  He told me that with the EFI system on this engine I do not need the EFE and EGR stuff so its coming off.  That will free up the port on the intake manifold next to the thermostat housing for the new temperature sending unit.

THANKS for the assistance everyone...!!! 
« Last Edit: April 18, 2019, 10:51:11 AM by P-Js_BLKBRRD »
"BLKBRRD" & "Friends"


'78 Trans Am w/Pontiac 400, 4 spd, Hurst T-tops

MNBob

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Re: Temperature Gauge Sensor Location(s)
« Reply #12 on: April 19, 2019, 07:47:50 AM »
Thanks for the comments.  I got rid of the EGR and EFE systems along time ago.  EFE went with the headers and EGR was a factory bad idea IMO.  I have never wanted to tackle taking the TVS out of the head though; as it is hard to get at and I could see that going really bad.

Anyway, I have two temperature switches in the crossover now for the two speed fan.  I'll just use one of those for a new sensor when I get the Sniper QJ.  The Sniper has fan control built in so I will no longer need the switches.

I am surprised at your temp readings but I do not doubt them.  The crossover is the last place the hot coolant goes before returning to the radiator.  I will get get another look at this when when I have the two temperature sensors. 

Using the FCC makes the install easier.  I am going with a new tank and fuel pump in it.  This requires a new fuel line from back to front to the EFI.
1979 TATA Extreme TKO .64
Hedman elite; Pypes 2.5; Borla XS; MSD 6A; Edelbrock intake; open scoop; modified Q-jet; Powermaster 150; 4 core radiator/Mark VIII fan; RobbMc mini starter; subframe connectors; solid body mounts; fiberglass rear springs; poly sway bar and link bushings; 81 master; D52’s; Blazer disks; 225/60 & 235/60 17's TrueContact's; relays for PW, PDL, lights; keyless entry

P-Js_BLKBRRD

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Re: Temperature Gauge Sensor Location(s)
« Reply #13 on: April 26, 2019, 02:52:18 PM »
The FI-Tech setup also has fan control built-in, which I won't be using until the budget allows me to get an electric fan setup.

The FCC sold itself to me.  Not having to do any other plumbing of return or vent lines was a plus.  A new fuel tank was part of the restoration 10 years ago so didn't want to revisit that.

Haven't been able to find an EGR block-off plate yet (Ames Engineering didn't even know of one!) so will just leave all that junk hanging on the engine for the time-being until I can either find one or end up fabricating something.
"BLKBRRD" & "Friends"


'78 Trans Am w/Pontiac 400, 4 spd, Hurst T-tops

MNBob

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Re: Temperature Gauge Sensor Location(s)
« Reply #14 on: April 27, 2019, 08:19:25 AM »
I just made one from 1/4” aluminum plate.  You can make a pattern from the old EGR.
« Last Edit: April 27, 2019, 08:27:47 AM by MNBob »
1979 TATA Extreme TKO .64
Hedman elite; Pypes 2.5; Borla XS; MSD 6A; Edelbrock intake; open scoop; modified Q-jet; Powermaster 150; 4 core radiator/Mark VIII fan; RobbMc mini starter; subframe connectors; solid body mounts; fiberglass rear springs; poly sway bar and link bushings; 81 master; D52’s; Blazer disks; 225/60 & 235/60 17's TrueContact's; relays for PW, PDL, lights; keyless entry

Re: Temperature Gauge Sensor Location(s)
« Reply #14 on: April 27, 2019, 08:19:25 AM »