In the midst of installing the new Holley Hyperspark distributor, ignition box and coil, detailed here, I decided to make a few other upgrades to the 1972 Pontiac LeMans. My vision for this car is to make it a great grand touring car. I want it to be reliable and comfortable for road trips. With its enormous trunk, it is capable of hauling enough luggage for a week-long vacation for my wife and I, even considering the amount of clothes she packs for such a trip (she is reading this thinking “Says the guy who once packed an entire suitcase of shoes”. What can I say? I like shoe options). The EFI has done much to make the Pontiac reliable for such road trips. No longer do I have to wonder “Is it warm enough that I don’t have to pump the throttle to start it and if I do, will it flood?” or feather the throttle when it’s cold until it warms up because the carburetor has no choke. Starting the car is simply a matter of turning the key to let the fuel pump pressurize the system and then firing it up. “Start anxiety” when leaving the gas station or winery, as a dozen people admire the lines of the LeMans, is gone.
To further this endeavor, I decided to install a new fuel gauge. The factory fuel gauge that Pontiac installed in 1972 worked. It was accurate. It knew approximately how much fuel was in the gas tank, even with the new tank and fuel sender. Its downfall was its readability. The needle in the gauge is dim and the Pontiac engineer who designed the gauge decided it should appear as though it were mounted in a cave. I resorted to carrying a mini flashlight in the car to shine on the gauge, lest I run out of gas. Turning the lights on helped the matter a bit, but the dash lights aren’t the brightest, and the flashlight ended up being the best solution. The LeMans’ fuel mileage of seven miles per gallon necessitates constant monitoring of the gauge, so this situation was less than ideal.
My ultimate solution was to install an auxiliary gas gauge, mounted under the dash. I kept the factory gauge in the dash, but it had to be rendered inoperable for the aftermarket gauge to work. Should I ever decide that I prefer to not know how soon it is until I run out of gas, it will be a simple matter to wire it back up. The single criteria that I chose for the new gauge was legibility. I didn’t care if it looked period correct. I didn’t care that the popular new YouTuber thought it was the next big thing in coolness. I wanted to know, at a glance, how much gas was in the car. I chose the AutoMeter digital fuel level sender, #4910. This gauge is 2-1/16″ in diameter, and has a blue digital readout, showing how much fuel, as a percentage, is in the tank. The ohm range matches that of the sender, so no programming is necessary, though the unit can be programmed if one is dealing with a different sender.
Installation involved mounting the gauge in a gauge pod and running wires to the appropriate location. I had a two-gauge mounting pod from the 24 Hours of LeMons NachoFriend Racing Celica that we no longer used, AutoMeter # 2237, and since I was installing another gauge, this would work perfectly. I mounted the pod under the ash tray. To wire the gauge, one wire was sent to a 12 volt ignition source with a 1 amp, 3 AG fast-acting cartridge fuse (Littelfuse #312001). The purple wire was run the length of the car, under the carpet, to the original fuel gauge sender wire. The black wire went to an engine ground.
The oil pressure gauge that was to share the pod with the new fuel gauge was AutoMeter #6927, also a Cobalt digital gauge. My LeMans came from the factory with an idiot light in place of an oil pressure gauge. I assume the idiot light worked, but an actual gauge provides much better information. One can see what normal oil pressure is when cold, when warm and identify a trend if the pressure starts to read lower than normal. I believe a gauge is a much better solution. What if our kids came with idiot lights instead of report cards? If their grade starts to slip, a parent can have a talk with them, tell them to step it up or they are getting a Prius when they turn sixteen. The student can rally, work harder and earn a real car. If they had an idiot light that goes off when all their grades fall below a D, it’s too late to do anything. A parent would just have to shrug their shoulders and remodel the basement for its permanent inhabitant.
Installation of the oil pressure gauge requires that AutoMeter’s sender (included with the gauge) be installed in place of the factory oil pressure sender. I applied some sealant to the threads of the new sender, removed the old one, and screwed in the new one.
AutoMeter’s sender is larger in diameter than the factory piece. The oil pressure sender for Pontiacs is located right above the oil filter. I discovered that the new sender was too girthy and interfered with the oil filter. There were two solutions to this problem. I could buy a narrower oil filter that fit my Pontiac 400, or I could get an adapter that moved the oil pressure sender further away from the oil filter. I chose the latter because I like my Wix oil filters and don’t want to change. I purchased a brass pipe fitting adapter, 1/8″ NPT male to 1/8″ NPT female, and it worked to help the sender clear the oil filter. One should be able to find this item at any of your better hardware stores. Maybe even at some of the shady ones. Other than running a wire to the sender, the wiring for the oil pressure gauge was identical to that of the fuel gauge.
The last “gauge” to mount was the handheld display for the Holley EFI. This display provides information such as RPM, water temperature, battery volts, ignition timing, air/fuel ratio and many other pieces of information. The LeMans came from the previous owner with a water temperature gauge mounted under the dash. Apparently he didn’t trust idiot lights either. With the Holley EFI handheld monitor providing me with the water temperature, I could eliminate this gauge from under the dash. I kept the steering column-mounted tachometer, since it is easier to read at a glance while keeping my eyes on the road. I drilled a new hole in the firewall, installed a grommet, ran the wires from the handheld to the ECU and snapped the wires in place. To mount the display, I purchased a magnetic phone mount made by TORRAS. These things are ubiquitous. The base is held to the dash with adhesive. A metal disc is attached to the handheld display mounting case. Insert the handheld display into the mounting case, and the magnet on the mount will hold it in place. The mount rotates so as to provide the best angle for the driver.
On the test drive, the gauges proved easily readable. I was happy to see that the values on the oil pressure gauge were what one would expect. The fuel gauge would only read intermittently. While driving, a value would flash on the screen and then it would read 0E (an error message). I suspect an inadequate ground for the gauge or the fuel sending unit and will diagnose this at a later date.
The last part of this project was cosmetic. The 18-inch US Mags Bandit wheels have the chrome center caps provided with the wheels. For years, I had wanted to install a factory-looking center wheel cap. I saw vendors that offered centers, but was unsure if I could make them work with these aftermarket wheels. Some internet searches revealed a company called 3D Car Stickers that makes 3D center cap emblems in whatever diameter you designate. They are two to three millimeters thick, with a durable adhesive, and are domed so as to not appear to be cheap. Four emblems cost only $8.99. The emblems I chose were red letters on a black background, reading “PMD” (Pontiac Motor Division). The emblems are made in the Ukraine. Delivery time, especially during COVID, is long. It took eight weeks to receive mine each time I ordered (I also got a set for the BMW 2002). I also ordered a set of four extra US Mags center caps to which to attach the new emblems, so I could go back and forth between looks.
To further improve the “grand touring” aspect of the LeMans, I’d like to better insulate the car from sound. It’s a loud car on the freeway, particularly with the 3.50 rear end and the 4-speed transmission with no overdrive. The sound system warrants an upgrade. It currently consists of a receiver in the dash and two speakers in the rear deck. The car would benefit from some sort of insulation as a barrier to road noise. I might soften the ride a bit, which is just a matter of adjusting a knob on each shock. The LeMans has evolved quite a bit from when I obtained it and its road manners are much improved. Be on the lookout for more projects in the future.