How To Add a Cylinder Head Temp Gauge
04-19-2005, 12:18 PM
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Three Wheelin'
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How To Add a Cylinder Head Temp Gauge
I finally was able to install my cylinder head temp gauge. I figured I would snap some pictures to share with all of you to show you how I did it. If anyone has a better way of doing it... I'd love to hear about it... Or if anyone sees anything that I have done incorrectly... Please speak up! I tried to submit this as one post... But it looks like I'll have to break it up into sections!
I have a 1990 C2 coupe... Obviously those of you with cabriolets will have to run your wires in a different manner. I did not have access to a lift or this job would have been much, much easier.
I am not a mechanic... Nor do I play one on TV but doing it this way did work for me. Total time from start to finish (Including runs to the store for parts and tracking down several ways to enter the cabin that ended up being a dead end) was about 4 hours. Doing it this way should be able to shave off A LOT of time... If you have eveything you need.
Parts and Tools Needed
Cylinder Head Temp Gauge package - Includes gauge, wiring, sensor and instructions.
4 Crimp-on female connectors (Some come with kit. I was shorted one in kit but wanted higher quality insulated type anyway.)
Drill
Coat hanger wire
2 feet of stiff wire
Electrical tape
screw drivers
10mm Socket or wrench to remove heat shield
Spark plug wrench
Dremel tool or a file and lots of time (Depending on your mounting method.)
Heat shrink tubing
Zip ties (Nylon tie straps)
2 wire taps to steal power for gauge light
Patience... Lots and lots of patience
I decided to mount my gauge where the spoiler up down switch is since I have a fixed spoiler. If this space doesn't work for you... They also make under dash mounts and even "pod" type mounts that blend into the top of your dash. I had toyed with the idea of making an A Pillar style mount but I didn't have the time to fabricate one.
First things first... I popped out the up/down switch and disconnected the backlight LED and pulled the switch out.
After disconnecting... The switch will get stuffed up in the hole behind the switches and gauge.
I removed the LED backlight and made sure I'd have the space to fit the gauge. There is a very narrow margin to mount the gauge in this location.
I have a 1990 C2 coupe... Obviously those of you with cabriolets will have to run your wires in a different manner. I did not have access to a lift or this job would have been much, much easier.
I am not a mechanic... Nor do I play one on TV but doing it this way did work for me. Total time from start to finish (Including runs to the store for parts and tracking down several ways to enter the cabin that ended up being a dead end) was about 4 hours. Doing it this way should be able to shave off A LOT of time... If you have eveything you need.
Parts and Tools Needed
Cylinder Head Temp Gauge package - Includes gauge, wiring, sensor and instructions.
4 Crimp-on female connectors (Some come with kit. I was shorted one in kit but wanted higher quality insulated type anyway.)
Drill
Coat hanger wire
2 feet of stiff wire
Electrical tape
screw drivers
10mm Socket or wrench to remove heat shield
Spark plug wrench
Dremel tool or a file and lots of time (Depending on your mounting method.)
Heat shrink tubing
Zip ties (Nylon tie straps)
2 wire taps to steal power for gauge light
Patience... Lots and lots of patience
I decided to mount my gauge where the spoiler up down switch is since I have a fixed spoiler. If this space doesn't work for you... They also make under dash mounts and even "pod" type mounts that blend into the top of your dash. I had toyed with the idea of making an A Pillar style mount but I didn't have the time to fabricate one.
First things first... I popped out the up/down switch and disconnected the backlight LED and pulled the switch out.
After disconnecting... The switch will get stuffed up in the hole behind the switches and gauge.
I removed the LED backlight and made sure I'd have the space to fit the gauge. There is a very narrow margin to mount the gauge in this location.
Last edited by Smokin; 04-21-2005 at 12:44 AM.
04-19-2005, 12:19 PM
#2
Three Wheelin'
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I masked off the front of the switch plate and traced an outline of the gauge... Knowing that I would need to cut to the INSIDE of this line.
After cutting out the bulk of this with a plastic cutting bit... I used a sanding drum to CAREFULLY finish it up. The sanding drum will remove a lot of plastic very quickly. I stopped 8 or 9 times to trial fit the gauge.
FINALLY.. It fits. I was going to paint the plastic but rationalized that the up down indicators and the "butt" end of the engine could also mean that the temps go up and down... and the "butt" end is where the cylinder heads are located.
Besides... I didn't want to risk the shades of black being different!
Clean up the back and install the gauge mounting strap... Neatness counts!
After cutting out the bulk of this with a plastic cutting bit... I used a sanding drum to CAREFULLY finish it up. The sanding drum will remove a lot of plastic very quickly. I stopped 8 or 9 times to trial fit the gauge.
FINALLY.. It fits. I was going to paint the plastic but rationalized that the up down indicators and the "butt" end of the engine could also mean that the temps go up and down... and the "butt" end is where the cylinder heads are located.
Besides... I didn't want to risk the shades of black being different! Clean up the back and install the gauge mounting strap... Neatness counts!
04-19-2005, 12:20 PM
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Now... The hard part! On my car I removed the heat shield on the passenger side rear (Sorry... forgot to snap a picture of this step... I did that part the day before.) and pulled the bottom middle sparkplug. I then fit the sensor over the end and bent the ring per instructions. They stress exactly where to make your bend if needed to install. I did not take the compression washer off. I have heard of some people removing it and others that don't. It looked like a good fit to me and I don't see where less than a 1mm spacer is going to hurt the performance of the plug.
I started looking for a place to run my wire from there into the engine bay. I figured I would slip it through the rubber skirting below the oil filter.
I figured where the skirt might rub on the wiring and added two layers of heat shrink tubing for protection. (Shown before securing the second layer.)
I installed the spark plug making sure not to bind the sensor on anything. The sensor wire is covered with a fiberglass type insulation for protection. This is not a very good shot as my my flash couldn't make it down the hole... But you get the idea.
I started looking for a place to run my wire from there into the engine bay. I figured I would slip it through the rubber skirting below the oil filter.
I figured where the skirt might rub on the wiring and added two layers of heat shrink tubing for protection. (Shown before securing the second layer.)
I installed the spark plug making sure not to bind the sensor on anything. The sensor wire is covered with a fiberglass type insulation for protection. This is not a very good shot as my my flash couldn't make it down the hole... But you get the idea.
04-19-2005, 12:21 PM
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Another bad shot of the heat shield back in place. (Tough to get the camera to focus at this range!) You can see where the lead comes out of the heat shield near where the plug wires are. You can see the lead slipping up into the engine bay... With the heat shrink tubing for protection. By the way... The sensor wire doesn't interefere with putting the spark plug boot back on.
Okay... You've used up a lot of patience by this time... You'll need more now. I was wondering where to enter the cabin. (Thanks to Jack Olsen and Jason Andreas for their suggestions.) I decided the easiest way was to come up through the rear shelf. My rear shelf was only held in with two screws. I see where there might be four in some. (I think the PO of my car left out the top screws when he re-did the interior) At any rate, you'll need to pull the rear shelf. You will have to unhook your speaker wires and take it out of the car. After unscrewing the shelf, gently pull it backward and you should be able to access the speaker wires. I started looking for the perfect spot... Some place on the side where it would not (obviously) interfere with anything else. The shot below is where I decided to come through. It looks as if a bolt of some sort is supposed to go there but the threads were still painted indicating to me that it had never been used for anything. I'm not sure what it was for... And there are many ways to get into the cabin... But that is where I decided to come through... I drilled a small hole through the sheet metal that was below the bolt hole. Then I used a coat hanger to poke a hole through the engine bay insulation. I then used stiff wire to go through the hole into the engine bay and secured the wiring to the piece of stiff wire with some electrical tape. Then you can pull the wiring into the cabin. This shot is taken looking directly down onto the rear shelf from outside. You can see the weatherstripping (out of focus) at the bottom of the picture.
EDIT - While you have the rear shelf out... Take the time and thoroughly clean your rear window... And treat your rear shelf to a liberal coating of vinyl cleaner and preservative. While the rear shelf is in... It's hard to get to all the areas. When you reinstall it... It will look brand new!
This picture shows where the wires enter the cabin in the engine bay. I used nylon tie straps to neaten it up.
There are any number of ways to run your wire from here. I ran mine down the corner of the carpeting, tucking it in so it's out of sight. I carefully ran it through the bottom of the passenger side seat... making sure it would not interfere with anything should the seat be moved forward or backward. I continued to the front of the car. The picture below shows the route I chose with a yellow line. It is very easy to tuck the skinny wires out of sight. My carpeting was very firmly glued down so I couldn't just pull it up and put the wiring below. Your car may be different.
Okay... You've used up a lot of patience by this time... You'll need more now. I was wondering where to enter the cabin. (Thanks to Jack Olsen and Jason Andreas for their suggestions.) I decided the easiest way was to come up through the rear shelf. My rear shelf was only held in with two screws. I see where there might be four in some. (I think the PO of my car left out the top screws when he re-did the interior) At any rate, you'll need to pull the rear shelf. You will have to unhook your speaker wires and take it out of the car. After unscrewing the shelf, gently pull it backward and you should be able to access the speaker wires. I started looking for the perfect spot... Some place on the side where it would not (obviously) interfere with anything else. The shot below is where I decided to come through. It looks as if a bolt of some sort is supposed to go there but the threads were still painted indicating to me that it had never been used for anything. I'm not sure what it was for... And there are many ways to get into the cabin... But that is where I decided to come through... I drilled a small hole through the sheet metal that was below the bolt hole. Then I used a coat hanger to poke a hole through the engine bay insulation. I then used stiff wire to go through the hole into the engine bay and secured the wiring to the piece of stiff wire with some electrical tape. Then you can pull the wiring into the cabin. This shot is taken looking directly down onto the rear shelf from outside. You can see the weatherstripping (out of focus) at the bottom of the picture.
EDIT - While you have the rear shelf out... Take the time and thoroughly clean your rear window... And treat your rear shelf to a liberal coating of vinyl cleaner and preservative. While the rear shelf is in... It's hard to get to all the areas. When you reinstall it... It will look brand new!
This picture shows where the wires enter the cabin in the engine bay. I used nylon tie straps to neaten it up.
There are any number of ways to run your wire from here. I ran mine down the corner of the carpeting, tucking it in so it's out of sight. I carefully ran it through the bottom of the passenger side seat... making sure it would not interfere with anything should the seat be moved forward or backward. I continued to the front of the car. The picture below shows the route I chose with a yellow line. It is very easy to tuck the skinny wires out of sight. My carpeting was very firmly glued down so I couldn't just pull it up and put the wiring below. Your car may be different.
Last edited by Smokin; 04-24-2005 at 12:05 PM.
04-19-2005, 12:22 PM
#5
Three Wheelin'
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Time to hook up the gauge! I originally cut the female connectors off the wiring so I could pass them through the hole I drilled in the shelf. I DID NOT CUT OFF ANY LENGTH OF WIRING. I ended up only removing about 3/16 of an inch of wire. It is important that you do not try to shorten the wiring as it may change the resistance... and the resulting gauge readings. You can hide any excess wire you may end up with... There are lots of places! I didn't figure that 3/16 of an inch would matter... Plus I wanted higher quality connectors! I also tapped into the power for the LED that lights the up/down switch using wire taps. The blue/white wire is positive (+) and the brown wire is negative (-).
The gauge barely fit... But it did fit where is was supposed to. I think it looks like it came stock in the car.
As Jack Olsen pointed out in his earlier post... This is an "always on" gauge meaning that it will always show the temperature regardless whether your car is turned on or not. The gauge light obviously only lights up when you have your lights on.
The gauge works beautifully! I have not taken the car out and run it yet. I did take the car out of the garage and let it idle for about 10-15 minutes. I saw temps between 200 - 225. Jack says his shows between 200 - 250 in normal driving. I'll post back and let you know what temps I see. I just got my front spoiler back from the body shop so I'll probably install that before I take it out! (I'm taking pictures to post that too!)
Hope this is helpful to someone.
Rick
The gauge barely fit... But it did fit where is was supposed to. I think it looks like it came stock in the car.
As Jack Olsen pointed out in his earlier post... This is an "always on" gauge meaning that it will always show the temperature regardless whether your car is turned on or not. The gauge light obviously only lights up when you have your lights on.
The gauge works beautifully! I have not taken the car out and run it yet. I did take the car out of the garage and let it idle for about 10-15 minutes. I saw temps between 200 - 225. Jack says his shows between 200 - 250 in normal driving. I'll post back and let you know what temps I see. I just got my front spoiler back from the body shop so I'll probably install that before I take it out! (I'm taking pictures to post that too!)
Hope this is helpful to someone.
Rick
04-19-2005, 05:28 PM
#6
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Excellent writeup, I would add two minor things that you probably already did but weren't obvious in the post... Prime and paint the hole that you drilled through the sheetmetal and find a way to seal the hole with a grommet, water is going to find its way into the cabin. The other thing I would check is if the insulation on the wire is gasoline and oil resistant, most isn't and it looks like you ran the wires near the fuel filter? At the very least I would paint the hole you drilled otherwise I guarantee it will rust out.
Last edited by bhensarl; 04-20-2005 at 11:09 PM.
