JuggernautOfWar

Edit: I took some pictures of the setup my car has right now. It's very different from what I've been reading on here. Here is the album:
http://imgur.com/a/WFVWV

I'm thinking about just getting an oil and temperature gauge set online and going aftermarket. If done right they are more accurate and reliable anyway, though look more tacky. Should I get temp and oil gauges online with all the wiring and adapters in a pack? Do they even come in a pack?

My '82 350 Berlinetta temperature gauge does not work. When I bought the car the PO told me the temp gauge didn't work because the needle was stuck all the way "hot" and did not move at all. He installed a really crappy aftermarket temp gauge on the passenger side of the interior, under the dash where passengers feet belong.

Soon after purchasing the vehicle the factory temp gauge needle must have loosened up or something, because it fell down to a new "cold" (like the engine is off) position. As far as I've seen the stupid aftermarket gauge doesn't even work right anyway.

So I'm here because I don't know where the temp gauge wire is supposed to plug into the motor to get its measurements, and I need to diagnose the factory gauge to see if it in fact works. I do not know how to do this.

It's been getting over 90 F here lately so I'm not comfortable having a car that may or may not be running hot.

Any advice? Thanks!

Scorpner

iTrader: (4)

The temp sensor is located on the drivers side between the first and second spark plug (#76 in image below).


You will need the correct sending unit for the factory gauge to work. I would check the gauge before paying for a new sending unit. Unfortunately, I don't recall how to test the gauge off hand but it should be fairly straight forward and/or you can find it by searching here, Google or Youtube.

You can either get an infrared temp gun to check right away, or you can grab another after-market gauge for $10-$20 that will be more accurate than the factory one. The one I have was tested before installing so I know it's accurate.

JuggernautOfWar

Alright so I need to check the sensor, gauge, and sending unit. I figured the sending unit and sensor would be in the same component.

I'd prefer to maintain the stock gauges for the time being and take out the crappy aftermarket gauge the PO installed. It may not be accurate down to the degree, but it tells me if the engine is overheating which is what I need. Eventually long down the road I'd like to replace the whole gauge cluster with something higher quality, but for now factory stock is what I'm doing.

I've been doing some reading on here and one gentleman suggested "removing the wire from the temp sensor in the head and touch it to the block. Then watch what the gauge does. If nothing your temp gauge is faulty or the wire from the temp sender unit to the gauge is damaged." To me this doesn't make sense since the wire itself is not a sensor so it cannot not relay any information without the sensor.

Scorpner

iTrader: (4)

I actually picked up mechanical temp and oil gauges at Walmart. lol I'm not sure if they still carry them though. I had an engine built and didn't trust the factory ones (or the after-market one I got at first) so I tested it in boiling water to be sure. I installed it temporarily in the inside corner up by the center console (see below), but ended up leaving it there since I haven't had a reason to remove it. I used a single screw already there to mount the gauge so it doesn't affect anything if/when I ever remove it.

This looks similar, I can't tell you for sure if it's the same brand or not. I paid closer to $10, this one is probably closer to the cost of a sending unit so it's up to you.
http://www.walmart.com/ip/Equus-2-El...Gauge/17470860

If you haven't looked, here are a couple of videos that I found quick that should explain things. I didn't have time to watch them and it would be better with an '80's Thirdgen but it should give you an idea on the basics and what to search for on youtube.
Edit: I noticed he used 12v from the battery which is way to high from what I remember. I recall the gauges work on 5v so I would want to try 3-5 volts on the gauge instead.
http://www.youtube.com/watch?feature...MZSXoCXwDQ#t=0
http://www.youtube.com/watch?feature...xV6M7Ror5c#t=0

Scorpner

iTrader: (4)

In that case they are grounding out the wire which completes the circuit. GM often uses ground (Ie. engine block or frame) as part of the circuit. The sensor is a simple resistor that varies with temperature and grounding it represents zero resistance. The sensor does not send any kind of data signal if that was what you were thinking, it just fluctuates the voltage.
Edit: That's the part I would have to check into. I'm not sure how the gauge is grounded and whether to send voltage to the gauge or ground it. That's why I didn't describe that part. The video I posted said to do the opposite, but that's a'90's version GM cluster.

Scorpner

iTrader: (4)

Here is a diag for an '86 Firebird. That's as close as I can get. The problem is they just describe a "Jxxxx" tester which you don't have, but it's the same principle of sending 0-5 volts (iirc) to the gauge. BTW, I agree with keeping it stock, it depends on what your goals are.

I had to reduce the image size to upload it. I hope you can see it.

JuggernautOfWar

Thanks for all the awesome advice guys! I just let my car warm up quite a bit and checked the installed aftermarket gauge. It never moved at all. Additionally, the mount is bent and the bulb for the gauge is missing. So basically my passenger side installed temp gauge needs to go.

I took some pictures of the setup my car has right now. It's very different from what I've been reading on here. Here is the album:
http://imgur.com/a/WFVWV

I'm thinking about just getting an oil and temperature gauge set online and going aftermarket. If done right they are more accurate and reliable anyway, though look more tacky. Should I get temp and oil gauges online with all the wiring and adapters in a pack? Do they even come in a pack?

fteufert

Where can "good" replacement temp senders be purchased (for a 82 Trans AM)? Are Autozone, Pepboys, and advanced auto parts any good?

JuggernautOfWar

Went to Napa and they had a gauge kit with all the wiring, adapters, and stuff I'd need. It was plastic and I'm not sure of the quality though for $52.

Can you guys recommend a kit that has everything I'd need or should I go with the Napa kit?

Scorpner

iTrader: (4)

Yeah, I'd say that the wire on that gauge could even have been pinched in the hood area. I used a grommet through the firewall for the temp gauge on mine. That's the way GM ran wires through to the dash so I like to try to do the same.
A lot of people run the triple gauge kit under the middle air vents. I didn't want to start putting screws into my dash if I didn't have to. If you search on here you should be able to find a lot of ideas of what other people have done. They make pillar pods to if you want but that's usually for other types of gauges. Like I was saying mine were around $10 and pretty much temporary. I like the temp where it is though, out of the way and I don't think the passenger even sees it.
Remember when you're looking that there are mechanical and electronic gauges, so decide first which you want. An oil gauge will have oil coming into through a tube so you want to make sure it doesn't leak, otherwise you'll want electronic. Jegs or Summit have a huge selection of styles and quality so that's up to you.

fteufert, yep that's about all you can do is have them look up the replacement part. I don't know if GM still carries something like that or not.

rusty vango

you can apply 3v dc to the green wire that is supposed to attach to the temp sending unit in the head. if you do this ,you should see the gauge go to the half way mark. if it does. it is working

mmadden55

http://www.summitracing.com/search/d...er-temperature

sofakingdom

iTrader: (1)

That is correct.

The sending unit is a variable resistance; it's very high resistance when cold, very low when hot. In fact that EXACTLY mimics an idiot light sender, except that instead of being just on/off for the light, it's gradual. And also in fact, if you hook an idiot light sender to a gauge, that's EXACTLY what happens: it reads zero at any normal operating temp, and pegs when the switch says "hot" (lights the light). Which is what disconnecting and grounding the wire does; simulates the same electrical conditions as zero temp and max temp. If the gauge goes to zero when you disconnect it, and full-scale when you ground it, then the gauge and wiring are working, and the sending unit is all you need to replace. If that doesn't happen, then you have to dig a bit deeper.

Start simple, proceed to the more complex only if necessary. See my signature for a helpful mental discipline.

naf

iTrader: (7)

In my experience, if the guage has been pegged 'hot' before it will eventually do it again. If you need one, replacement temp guages for our cars are available as a GM reproduction piece.

JuggernautOfWar

Yeah I've decided to not even use the factory gauge and just get aftermarket temperature and oil gauges. Do you guys have any gauge packs you recommend that come with adapters and everything I'll need?

http://imgur.com/a/WFVWV
As you can see the current temperature gauge is not at all like in the diagram in this thread.

rusty vango

hahaha that's hilarious!! just replace the gauge in the cluster with a new one and replace the sending unit in the left head and all will be good. PLUS it will look and act as original