Whether you race, tow or simply drive to and from work, keeping a close eye on the various engine operations is vitally important to the health and well-being of your truck and the only way to do that is with gauges. Gauges allow the operator to know, at all times, exactly what the engine is doing, or in the case of oil pressure, not doing, so that said operator can take the appropriate measures to save himself and his ride from potential disaster.
The OEM's have done a good job of covering the basics in that they have added gauges that cover water temp, oil pressure, voltage, fuel level and the like. These are fine for gas engines, but diesel drivers have additional needs that go beyond these basics. Gauge readings can help with troubleshooting and diagnostics and knowing things like exhaust gas temperatures are critical when towing. Fluctuations in boost pressure and fuel rail pressure can signal oncoming issues long before they can become a problem. That's why in the long run, adding these gauges can save your engine and your money from going south.
PPE knows how to get a diesel engine to produce big horsepower, but they also offer a line of gauges that allows you to be sure that your engine is performing to its optimum level and doing it safely as well. The big three of diesel gauges are Boost Pressure, EGT and Fuel Rail Pressure, and PPE offers them all. Equipped with Optix stepper motors, these gauges offer superior response, action and reliability. All PPE gauges feature an easy-to-read OEM style red pointer over black face with white numbers, all of which is housed under a stylish black bezel. Bright LED backlighting provides plenty of light, but is dimmable when wired into the factory dash lights harness.
PPE also offers multiple ways to mount the gauges. One of the most efficient ways to mount gauges is to use an A-pillar mount. PPE offers two versions: one that holds three gauges and one that holds two. They also offer a nice billet overhead mount for Chevy owners.
For this install, we'll be using their Triple Gauge A-Pillar Mount and into it will go PPE's Boost Pressure, EGR and Fuel Rail Pressure gauges. The pillar comes in basic black, and can be painted to match the rest of your vehicle's interior. Getting the data to the gauges requires some disassembly of the truck, drilling of holes, cutting some hoses, breaking and then making electrical connections and running these leads to the cab area, but overall it's not that difficult an install, especially for this LB7. The LLY and LBZ engines require removing the air intake manifold, but even that isn't so bad. For those at home, figure a solid 6-8 hours of work and you'll be done.
Let's follow along as the crew at PPE gives an LB7's owner the ability to keep his eyes on his engine while he's also keeping them on the road. A full "how-to" video on this install is available on PPE's website (www.ppediesel.com), which shows exactly how easy it is to add these gauges to your truck.
The Big three of diesel-specific gauges: fuel rail pressure, EGR and boost pressure. These PPE gauges will provide an inside view into the engine and will provide the driver with the info that he needs to drive safely, even under heavy towing or race conditions.
The pyrometer and lead wires for the ETG gauge (L) and the plastic tubing for the Boost Pressure gauge (R) come with the gauges.
These two leads, one for the Fuel Rail pressure gauge (L) and a T-fitting equipped rubber hose are optional. It's possible to splice into the FRP harness (though we really don't recommend it) and to make your own fitting and hose assembly, but PPE has done the work for you. Simply purchase these pieces from PPE and it will make the installation process much easier.
PPE offers this three-gauge, A-pillar mount. It comes in basic black, but can be painted easily to match OEM interiors. It can also be had in a dual gauge setup.
SEM makes Classic Coat flexible paint that comes in OEM colors, and was used to match the "Very Dark Pewter" interior color of this Chevy.
For those who want to place a pair of the gauges into their Chevy/GMC overhead console, PPE offers this billet unit. It is available with or without switches and can be had in a polished, brushed or black finish.
The gauges will be going into a 2001 LB7. This makes things easier when dealing with the Boost gauge aspect.
You have to start somewhere, so we started with the EGT sender. To gain access to the exhaust manifold, the inner fender well is removed.
Rather than pulling and drilling the manifold off the truck, here's a little trick to make this part of the install easier: start with a cold engine, then start the engine and drill the 21/64-inch hole. Since the engine is running, the exhaust itself will blow the shavings out of the hole. Do NOT simply drill and tap the hole without removing the shavings in some way, as they may damage the turbo when they pass through.
A lubricated NPT 1/8-inch tap is used to cut the threads. Again, the engine is running during this process to force the shavings out.
After giving the threads a few shots of lube, the fitting is inserted into the manifold.
The electrical leads from the pyrometer probe are connected to the main wire. Note that they are color-coded and have alternating length to make the job easier.
A heat gun shrinks the heat wrap over the connections, making the connections water-resistant.
The pyro probe is inserted into the fitting and tightened up. The lead wire is fed up and will be grouped with the other wires and tubing and zip tied to the firewall.
Care needs to be taken when cutting the plastic boost tubing, especially if using side cutters and not a razor blade. To ensure a good seal, the cuts need to have a very square finish and the end needs to be rounded back out before installing it into the compression fitting.
On the LB7, there's a handy boost tube that runs from the air intake manifold to the wastegate. The rubber tubing is cut, and then a small section (1/4-inch) is removed. The T-fitting and hose are installed and hose clamps are used to secure them into place. Getting a boost reading on the LLY and LBZ is another matter. Check out the sidebar for more information on these engines.
The electrical connection for the Fuel Rail Pressure sensor is unclipped and the PPE wiring harness is installed. The PPE harness simply snaps into the two ends and then leads off to the gauge. Believe us when we say that using the optional PPE harness is much easier than trying to splice into the existing one.
The leads from the Pyrometer, FRP and Boost tube are ganged-up and zip tied and run along the upper edge of the firewall. Note that the boost tube has been encased with a piece of high-temp plastic split loom for protection against heat and scuffing.
To gain access to the interior, a cut was made into this rubber seal using a utility knife and the assembled wires/hoses fed through.
With a good (careful) tug the dash and side panels will come away, providing access to the wiring inside.
The lower panel has screws running along its lower edge and clips along its upper edge. The screws are removed and then tugging will be all it takes to remove the lower panel.
The A-pillar is also held in place with clips, so it's removed the same way.
The headlight switch assembly is pulled out and the lead wire for the dimmer switch is located using a test light.
A T-Tap slide connector is used to make the connection for the gauge lights. By connecting to the dimmer, the gauge lights will dim with the rest of the dash lights. The wire is run through the back with the rest of the wires and the switch is reinstalled.
A good ground is everything when it comes to sound electrical function. It so happens that there are mounting posts for the dash right beside the side panel that are perfect for our needs.
The test light finds a key-on hot wire for the EGT and FRP gauges.
PPE recommends that the hot lead-to have an inline fuse to make sure the system is as safe as possible.
With the wire's connections made, they are run up and out of the top of the dash. The various panels are also reinstalled.
Time to prep the pillars. The three-gauge pillar pod doesn't so much replace the stock unit as much as it sandwiches to it. As stated, the new unit has been painted with the SEM Classic Coat "Very Dark Pewter" flexible paint.
With the two pillars mated to one another, 3/16-inch holes (three per side) are to be drilled next.
Plastic push fasteners are used to affix the two pillars together.
Three, one-inch holes are drilled into the back of the stock unit. These will allow the wire looms and tubing to be fed to the gauges.
Back in the cab, the connectors are removed from the gauges and the wires that will be running to the lights, power and ground are ganged-up together. The lead from the Fuel Rail Pressure sensor is attached to the leads from its connector plug.
The rest of the wires, such as the Fuel Rail Pressure, are connected to the gauge pigtails.
Getting the pillars back into position while pulling the wires and Boost tubing through their respective holes sort of requires three hands, but it's soon in place and securely affixed.
We know that most people will use side cutters or some other one-handed tool to cut the plastic Boost tube, but know that this will slightly deform (squash) the end of the tube. However you do it (pliers are best), make sure that the tube is round again before it's inserted into the fitting.
With the gauge pigtail wired up, they are then inserted into their slots behind the gauges. With their removable harnesses, wiring these new gauges is much easier than wiring the fixed post gauges of the past.
Fitting the gauges into the pillar requires a little effort. They're not supposed to be loose (and they aren't!) so make sure that you have them positioned perfectly (north, south, east and west) before you push them all the way in.
With that, the gauges and pillar are in and looking good. Now this vehicle's owner will be able to keep an eye on his ride and benefit from additional information that a set of PPE gauges will bring to his driving experience.
An Added Tip
Thanks to the rubber tube running to the wastegate, getting the boost pressure readings from the LB7 is pretty easy; just cut that tube and insert the T-fitting. The LLY, LBZ, LMM and LML however, are not quite so easy. Getting a Boost reading from these engines requires that the air intake manifold be removed from the vehicle and the hole for the Boost fitting be drilled and tapped. It's not possible to do so without removing the piece so that no shavings from the drilling process are allowed to enter the engine or bad, very bad things will happen. The PPE technicians prefer to drill the holes in the rear of the intake, as this is the cleanest when it comes to routing the tubing.
There's plenty of room on the LLY, but the LBZ, LMM and LML are a little tighter. It's also the easiest of the bunch when it comes to accessing and removing the air intake manifold, but for all of them, the results will be well worth it.