The Diesel Garage.Com Gauge Install Page

On this page we will highlight the installation of a set of gauges. The first will be on a 7.3L Powerstroke, with the second on the 6.0L Powerstroke. As with any project, be sure to sit down with the instructions supplied and make sure you have all the parts listed. It's far easier to deal with missing parts before the install begins, than to chase or order missing parts halfway through the project. 

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Tools Needed:

Drill and drill bits, including size "R" bit

Tap and Die set

Set of Metric wrenches

12v test light

Teflon tape

Wire cutters/strippers

Electrical Connectors

18 gauge wire

7.3L Powerstroke

Pyrometer:

-The Pyrometer is one of the more important gauges you can have in a diesel truck, especially if you have an aftermarket chip or tuner installed. The pyrometer measures the temperature of the exhaust. Typically, anything over 1350 degrees Fahrenheit for an extended time will cause damage to the pistons. You will achieve a more accurate reading by installing the pyrometer pre-turbo. To install the pyro, find a flat spot on the drivers side exhaust manifold. Begin by drilling the smallest possible hole, and slowly stepping up in sizes until you get to the size “R” drill bit. (See figure 1) Remember that while you drill, small metal shavings will be falling down on top of you, so some sort of eye protection gear recommended. Once you have the hole drilled, it’s suggested to use a shop vac to vacuum out any shavings. It may prove helpful to disconnect the front driveshaft from the axle for more room. Now you will use the 1/8” NPT Tap to thread the hole. Once you have that done, install the pyro probe, tighten as necessary, and run the wires to the top of the engine bay. (See figure 2) NOTE: most pyrometers are tuned to the length of wire supplied. Do NOT cut or splice the wire that hooks up to the sending unit. The pyrometer may not work correctly if you do.

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figure 1

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figure 2

Transmission Temperature:

-This is probably the next most important gauge to have installed. Today’s transmissions are built to exacting standards. When you tow heavy loads, or do a lot of racing or off-roading, the added stress to the transmission can cause it to overheat, leading to premature failure. By keeping an eye on the temperature of the transmission, you can determine if added cooling capability is required for your transmission. To install the temperature sending unit, locate the high pressure test port that is on the driver’s side of the transmission, just ahead of the wiring harness. (See figure 3) The side plug is 1/8” NPT, and most if not all gauge manufactures have a sending unit that screws directly in, or screws in with the help of an adapter. When you unscrew the factory bolt that is in the hole, there might be some weeping of transmission fluid. But, if you are quick, you can install the new temperature sending unit with little if any loss of transmission fluid. NOTE: if you use some Teflon tape around the threads of the sending unit, be sure that the sending unit does not ground to the pan. If it does, the tape may prevent adequate grounding which may result in inaccurate readings or gauge failure. Once you have the sending unit installed, then run the wiring harness up to the top of the engine bay. If a wiring harness was not supplied, use the suggested gauge of wire found in the instructions.

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figure 3

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figure 4

Boost:

-This gauge measures boost pressure being built by the turbo. It’s measured in  pounds per square inch (psi). Many aftermarket chips and tuners will create higher boost pressure than what is possible in stock form, and this gauge allows you to measure that. One could argue that this gauge is more of an ego gauge. But, the coolness factor can not be denied. There are mechanical and electrical boost gauges. The electrical gauge does not require the installation of a vacuum line to the back of the gauge. The mechanical gauge does. For the mechanical gauge, there are a couple of ways to install the fitting. One can either drill and tap the “Y” pipe in front of the turbo (See figure 4), or one can splice into the MAP line with a “T” fitting. This writing will cover the electrical gauge. The sending unit will be mounted in the “Y” pipe in front of the turbo. Remove the CAC tube from the “Y” pipe and stick a clean rag into it. Just be sure you are able to remove the rag. Mark where you want to mount the sending unit, and just like with the pyro, start with the smallest bit and work up to the size “R” bit. Then use the 1/8” NPT tap to thread the hole. Wrap the sending unit threads with a little Teflon tap and screw the sending unit in. (See figure 5) Snug it down but do not over tighten. Hook up the wiring harness and route the wires to the master cylinder. (See figure 6)

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figure 5

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figure 6

Engine or Coolant Temperature:

-This gauge measures the temperature of the coolant. You will be able to determine how your thermostat is behaving with an engine temperature gauge. Diesels are most efficient at approximately 200 degrees Fahrenheit. On Ford Powerstrokes, they come equipped with a 195 degree F thermostat from the factory. These thermostats will begin to open somewhere between 165 degrees F and 170 degrees F. If you notice that your engine temperature gauge never gets above 160 degrees...your thermostat may be stuck open and in need of replacement. If you consistently run warmer than 200 degrees F, your thermostat may be stuck partially closed. Again providing a clue that your thermostat may need to be replaced. For this install, the coolant temperature sending unit was mounted in an available port on a coolant filtration head. (See figure 7) The sending unit is 1/8" NPT but the port is 3/8" NPT. Autometer provides a 3/8" NPT adapter just for this situation. If you do not have a coolant filtration kit, another possible port to use is on top the water pump. On most 7.3L water pumps there is a secondary port that has a 1/2" plug. Unscrew that plug, use the provided 1/2" NPT adapter and install the temperature sending unit there. *NOTE...the cooling system is under pressure. Be sure to let the engine cool before working on the coolant. Open the degauss cap to relieve pressure. You may also have to lower the coolant level some so that coolant doesn't come gushing out of the water pump access port. 

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figure 7

Gauge Install:

-Now comes the fun part of powering and hooking up the gauges. There are several mounting options for the gauges, from dash mounted pods, to overhead mounted pods, to mounting them on the A-pillar. This write-up will cover the A-pillar mount. First…remove the weather door seal around the door frame. This just pulls down. Once you have this out of the way, gentle pry the plastic A-pillar cover off. This just pulls off. Next, inside the engine compartment under the master brake cylinder is a diamond shaped piece of plastic. This is only on automatic transmission equipped vehicles. Pry this plastic piece off. (See figure 8) Then, on the inside, near where the computer is mounted, is the foam piece that needs to be removed. (See figure 9)

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figure 8

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figure 9

 Drill a hole in the plastic piece big enough for a rubber grommet to be installed and for the wires to be fed through the firewall. Take your gauge wires, feed them through the drilled hole and into the cab of the truck. (See figure 10) NOTE: This is a good time to locate a good grounding location for the gauge set. I mounted my ground wire to a quarter panel nut in the engine compartment and ran that wire into the cab as well. 

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figure 10

For the gauges, you will need to supply 3 wires. The first will be the 12v keyed source. This will power the gauges whenever the truck is started. In this instance the thick black wire with the green striped was used. (See figure 11) Whatever wire you choose to use, double check it with your test light to be sure its hot with the key and not at all times. You will also need a wire to run the back lighting for the gauges. You can either pop out your headlight switch, or look under the dash for the light blue wire with the red tracer. (See figure 12) This powers the gauge lights whenever you turn on the trucks lights. This also allows you to dim the gauge lighting, but beware that you have to dim the dash lights as well. The last wire you need to supply will be the ground wire. 

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figure 11

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figure 12

Now you want to take your painted pod, and overlay it on the A-pillar cover you took off. Hold them snug together and mark with a pencil where the holes need to be drilled for the side plastic pins, as well as marking where you need to cut holes in the factory pillar cover for the wires to run through. Once that is done, hook up the power supply wire, the dash wire and the ground wire to the gauge wires. As for the order of the gauges, let the length of available wiring harness dictate that. On the example truck, there was little left of the transmission temperature wiring harness, so it went in the bottom hole. Next came the coolant temperature, boost and lastly the pyro. Feed the gauge wiring harness ends through the your drilled holes in the A-pillar cover and mount the gauge pod to the cover using the supplied plastic pins. Feed the wires through the gauge pod holes, then re-mount the cover-pod combo. (See figure 13) Be sure to tuck all wires behind the cover and that the clips that hold the cover to the body are snug and secure. 

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figure 13

Now its just a matter of attaching the gauges to their wiring harness, and gently pushing the gauge into the gauge hole. You do not need to attach the gauge in any way to the pod. The friction between the pod and the gauge will keep the gauge from falling out. Once you have the gauges mounted, put the door weather stripping back into place. Now its time to see your finished product. (See figure 14) Start your truck and let it idle for a few moments. You should begin to see the pyro slowly climb as exhaust gas temperatures begin to warm. In order to see if the transmission temperature and boost gauge are working correctly, you will need to drive the truck around. Don't forget to turn on your lights to make sure that the backlighting works as well. (See figure 15)

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figure 14

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Figure 15

 

6.0L Powerstroke

Pyrometer:

-The EGT probe is an easy install from under the truck.  You can tap the manifold on the drivers side by starting with a small bit and working up.  You will need protective glasses on since you will be drilling directly above you.  In this case we needed to tap for a 1/8" NPT so we worked up to the "R" bit with the motor idling.  With the motor running, and using dry bits, the metal flakes get shot back out and you have little chance of anything getting to the turbo.  There are very few flat spots that you can find on the manifold, so use your best judgment.  You can see in the pictures where we thought the best spot would be.,

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figure 16

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figure 17

Boost:

-For the most accurate boost reading, and also not to take chances messing with readings by your map sensor, you need to drill and tap the intake.  This is very simple.  Before you remove the intake elbow, mark with a felt tip pen the spot you want to tap the intake. I found it best to route the boost line prior to this to fit everything in as neatly as possible.  Once marked ,we removed the 4 bolts, then the CAC tube, then removed the elbow, making sure not to lose the rubber o-ring.  This is aluminum, so it is easy to drill and tap, but be carefull not to twist the tap since the metal is soft.  Once tapped, install the brass fitting, install the elbow, and connect the boost line.

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figure 18

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figure 19

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figure 20

Transmission Temp:

-The Torqshift already has a 1/8" NPT plug in the spot that you will use for the temp.  All you have to do is locate the plug on the drivers side of the transmission, remove it and install the new transmission temperature sender.  You will only lose a drop or two of fluid, so take your time and don't cross thread anything. In this case the instructions stated to run 18 gauge electrical wire from the sending unit to the gauge. If your gauges don't come with a pre-wired harness from the sending unit to the gauge, use the recommended gauge wire on the instruction sheet. 

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figure 21

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figure 22

Gauge Installation:

-Removing the grab bar is simple, but there is one small screw that holds the bar in place during assembly that could throw you.  You have to remove the pillar to get at it, so once you remove the bolts holding it in place, don't try to rip it off! Route your wires from the engine compartment into the cab, then route them up to where the A-pillar locates. Gauge location on the pod will be determined by what length of wire or tube you have remaining. Run the wires through the gauge pod, then attach the pod/pillar combo back to the truck. Attach the wires to their respective gauge, slide the gauge into the pod. 

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figure 23

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figure 24

 
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