My car used to have a Hypertech thermal chip in it for a long time. I replaced it after many tests to identify the surging and stalling problem I had. For me it was the chip so I won't go into all of the various reasons for the surging problem. My surging and stalling went away. So I installed the factory 16083268 calibrator. So what I'm now seeing is my temperature gauge going to 260 degrees before the ecm turns the primary fan on. After a minute or two the primary fan turns off. My secondary fan does not turn on at all. A little history about the temperature gauge sending unit between cylinders 1 and 3. It went bad on me a couple of years ago and I picked one up at Autozone. This unit didn't work well so I replaced it again with another identical part number that, in my opinion, read about 200 at normal operating temperature. I' found that the same identical part number affected my gauge differently. The Hypertech thermal chip, I believe, turned on the primary fan sooner and kept the temperature in the gauge range I visually liked. Now with the factory chip, the primary fan doesn't turn on til 260 and turns off at about 240 or so. I felt that if the car was indeed overheating I would see the secondary fan turn on. I checked the wiring for both the primary and secondary fans and when I ground out the green/white wires going to either fan, they turn on. Since the primary fan is controlled by the ecm via the coolant temperature switch at the front of the intake manifold I am assuming that the ecm temperature is in conflict with the dash gauge sending unit. So I removed the wire from the CTS and used a VOM to check the resistance while at the same time with a second VOM connected to the gauge sending unit. Well the results for both sensors were different ohms readings at the same engine temperature. I found a table for the CTS ohms to degrees but I'm curious if there is a table for the gauge sending unit. I have the factory secondary fan switch in the passenger side head between 6 and 8 and it has the same connector as the knock sensor...round. So what I'm really trying to figure out is if the gauge sending unit is bad or out of calibration, the gauge is bad (it pegs if I ground it), my new calibrator is bad, the ecm is bad, or what. It doesn't seem like the engine is overheating at all at 260 degress so I'm thinking the gauge sending unit is bad. I'm just trying to find a table for resistance. I've found some tables for other cars but I don't trust those since different cars probably have different calibrations between the sending unit and gauge. Sorry for the long post. I might just go back to Autozone and try swapping the sending units again, may two or three times til it comes back into a comfortable range. I also used by thermal gun on various parts of the engine and it is not showing the engine is overheating.

I've searched on the forum for threads but haven't found any that address the resistance values for the gauge temperature sending unit.

Art

 

At this point I'm just going to replace all three switches and sensors. I bought them from Napa. I've had some problems with switches from Autozone, not very consistent.

Art

 

it should be
the coolant temp switch between cylinder one and two only goes to only your gauge
the coolant temp between 6&8 is coolant switch to turn a fan on and I believe is also grounded into the a/c
the coolant temp switch is above the timing cover and goes back to the ecm

 

I forgot about this post. I bought a couple of temperature gauges from Pick N Pull. I replaced the temperature gauge sending unit, the coolant termperature switch for the ecm and the coolant fan termperature switch. Even after changing out the gauge with the two other gauges the temperature range is about 110 while cruising and goes up to 250 when idling. One thing about this engine is it's in my 80 El Camino but it's wired exactly as if it's in a Camaro. So the good thing is it's not running hot, the gauge is just off. The primary fan comes on after sitting and idling like it's supposed to, the secondary fan pops on a minute after the primary fan kicks in so it's coming on like it's supposed to. The secondary stays on even after I turn the key off since the relay is wired to constant 12 VDC. So I think the primary is coming on around 230 then the secondary kicks in around 238 which is what I expect while the car is idling. The engine temp is very cool when driving but I haven't confirmed what it actually is. I'm not worried about it. New switches and sensors and it still runs good even though the gauge is off. I might try splicing in a 20-30 ohm resistor to bring the gauge reading down a bit. Thanks for the reply.

Art

 

I was going to suggest adding a resister I want to say our sensor is on 16 ohms equals 260 but that may just be the holley custom setup I was playing with. Id say try lower ohms first. Also tieing resisters going into the ecu may help. Do you have a third gen radiator the factory setup does run fairly hot I almost turned my car off first trip into town scared it was going to over heat lol. Also have you tried swaping gauges?

 

Hi, yes I put in the 3rd gen radiator and both primary and secondary fans. It seems that it has always read hot. I installed the entire interior from the Camaro into my El Camino so it has the Camaro dash gauges and wiring in it. It just seems like it's running hotter and probably is since I replaced the ADS Super Chip that, I believe, was turning on the primary fan sooner. Now that I have a stock chip in it I think it's just operating like it's supposed to...hot. I know I can change the secondary fan switch to come on cooler. It would probably come on sooner than the primary if I did that. I looked at a temperature gauge ohms to temperature chart and it seems that the low temperature range of the gauge uses a lot higher resistance between temperature readings. When the engine is at the 230 to 260 range the resistance between those two numbers is much lower. Something like 1600 to 1000 which is 600 ohms to move the gauge from 75 to 150 degrees and 50-85 ohms for 230 to 260. I'm just guessing off the top of my head but I think you get what I'm saying. That's why I'm thinking of putting in a 30 ohm resistor. It won't affect the lower end at all, just the upper end of the scale. I just need to figure out what size. Maybe install a potentiometer and adjust it to fit. I'll try to post some pics of the car, engine and interior for giggles.


Art

 

Another option is to wire the ground for the relay together if ur happy when the 1st fan turns on and want the 2nd one to turn on at the same time

 

Before I re-painted it due to a front-end mishap that destroyed the Camaro nose. This was one of my first paint jobs back in 1991 or 1992. I got tired of the Camaro nose since it was getting dated. I got into a little nose tap and decided to just change the front nose back to the 87 front-end. It's actually a 1980 EC with Corvette mirrors that are electric heat/defrost and adjustable. They look just like the 87 mirrors but function better. Many hrs to get the car here. Drove it for many years until I repainted it in 2012 and re-colored the interior with SEM.

 

And after new paint I did in my garage

 

Engine view

 

I've got switches in the car to turn each one on manually. Basically I extended the ground trigger wire inside. I'm going to hook up some leds so I can see when the fans kick in whether automatically or manually. I have had it wired with both relay grounds just tapped into each other. I decided to move them inside the car and do it with switches. Thanks for your replay.

 

That el camino does look pretty sweet I like the integration is the iroc ss on the door a sticker or did u spray it?

 

The IROC SS was an additional part to the body kit, it was extra. Each piece is separate from each other. It was sandwiched in between two pieces of filaments like wax paper. I peeled the one piece off the adhesive side then laid the entire piece on the door then peeled the backing off. I think that how most stickers are applied these days. Each piece even the fade stripes that are wider to narrower were individual. They are gone now since the repaint because there was no way to re-use them when I painted the car. For many years, and still today, it got quite a few comments. I don't know where else to go for any TPI info except this forum. I've been a member a long time. I think this is the first time I've really shared that I don't have a Camaro. I'll probably be shunned now...it's Blasphemy!!!

 

Yech if you add to the forums I don't see the issue I think ur vehicle is pretty cool . Heck I have a couple Camaros but I could see a L98 s10 project in my not so distant future lol

 

auto zone electrical parts are Chinese junk.good call going to napa. as for the gauge, its common for them to fail. you can find NEW oem temp gauges. I got mine NOS from franzen chevy.solved the issue

 

Very cool.
What is the dash and interior out of?
Was that a all bolt in?