Not everyone loves electronic diesel engines. Because of the “issues” with these new engines, there’s been a resurgence of older mechanical Caterpillar 3406Bs, as well as the Big Cam Cummins. It’s amazing how satisfied a trucker can be when he gets his mechanical engine dialed-in to where he likes it and knows that a sensor, ECM, wiring harness, DPF (diesel particulate filter), DEF (Urea) system, or a faulty throttle pedal won’t shut his engine down – because these beautiful older engines do not have any of those troublesome parts.
Last week I had an interesting phone call from Ron Johnson of Kouts, Indiana who owns a DDEC-4 in a Freightliner Classic. Ron came to our shop and had a new damper, balancer, manifold, turbo, and Pittsburgh Power computer installed in his truck. He also got a Kevin Rutherford (KR) “scan gauge” for his rig. Ron and I had a long conversation about driving and about the proper use of the turbo boost gauge and the KR scan gauge. We also talked a lot about not using the cruise control unless the terrain is dead level.
Well, last week Ron said to me, “I have been driving a truck for 18 years, but I was not driving it correctly. Now, I drive mostly with my right foot, always keeping an eye on the turbo boost gauge and the KR scan gauge, and I try to stay in direct gear and keep the boost low. The truck runs so freely now, that I can do 61 mph on just one pound of turbo boost and I average 8.5 to 8.8 mpg – sometimes I even hit 9.1 mpg. I never realized I was driving improperly until we talked in your office.” Think about what he just said – he’s been “driving improperly” for 18 long years! If your purpose is to make money and gain fuel mileage, then you must drive your truck right.
Think about this: 75% of the dirt above 10,000 feet elevation is in Colorado. So, picture North America in your mind as a large volcano, and the Continental divide in Colorado, near the Eisenhower Tunnel, is the very peak. If you’re traveling towards Colorado you are going uphill. If your route is from Montana to Texas, you’re traveling downhill. Where do most of the rivers in the USA end up? The Gulf of Mexico,
somewhere between Florida and Texas. Which way does water flow? Downhill. Look at the creeks and streams where you are driving. If you’re going against the current, you are going uphill.
Take a section of highway that runs along a stream and drive at a given speed, going with the flow of the water, and then turn around and go against the flow, and see how many more pounds of turbo boost it takes to go against the flow (uphill). Even the slightest of grades can really make a difference. Going with the flow will take about 4 to 6 psi of turbo boost, while going the same speed against the flow will take about 12 to 14 psi of boost. At low boost settings, an engine will develop about 30 horsepower per pound of boost. At high boost settings, a 12.7 Detroit will develop 16.6 hp per pound of boost and a Cat will develop 18 hp per pound of boost (the difference is in the cubic inches and in the stroke of the piston – the longer the stroke of the piston, the less turbo boost required to make power).
So, what I’m saying is, if you are always loaded going against the flow of the rivers, your engine is working harder and getting less fuel mileage than if your route is more “with the flow” (going downhill). The next time you look at a globe, look and see where the USA is located. When you are driving from south to north, you are always going generally uphill. Drive more with your right foot, use the turbo boost gauge and the KR scan gauge, and, whenever possible, choose “downhill” routes when loaded to help increase your fuel mileage and make you more money.
Switching gears, let’s talk a little bit about your “check engine” light. This light is illuminated by your engine control module (ECM) for various reasons. Unless you’re under warranty, all of them are going to cost you something to remedy. Depending on the condition, a problem detected by your ECM could be costing you horsepower, fuel mileage and money immediately. When you see a check engine light, your ECM is trying to tell you that it has detected a problem. It is in your best interests not to ignore this warning.
Most “check engine” faults are triggered by a signal that the ECM is set to interpret as an abnormal, inaccurate or unsafe reading. One example that comes to mind was an owner-operator with a 2000 FL with a Series 60 Detroit and a DDEC-4 ECM. The owner complained of poor fuel mileage, a “hard-start problem” in the winter, constant white smoke, and the engine fan would not disengage. We then looked into the diagnostic codes and found an “active” fault which indicated that the ECM had no connection to the oil temperature sensor. It turned out that the wiring to the oil temperature sensor had been butt-spliced twice and had corroded though until the ECM lost its connection to the sensor. A few feet of wire and a few properly-soldered connections was all he needed to fix all of his problems!
Never assume that because you do not see a “check engine” light, your engine sensors are accurate. It is often a worse situation when an ECM is using data that is inaccurate instead of detecting the problem and assuming a “middle-of-the-road” value for the sensor that it knows has bad data. Most shops will not check to see if a sensor is reading accurately unless that particular sensor has a fault code. At Pittsburgh Power, we look at the engine’s temperature and pressure sensors to verify accuracy. If we suspect a sensor calibration issue, then we use our TD-36 chassis dynamometer’s laboratory-grade pressure transducers and thermocouples to find how far off the sensor is and program sensor correction into the ECM. We can also verify your truck’s rated horsepower, your fuel consumption, and even your emissions (which we keep confidential, of course).
Drive right, pay attention to all of the small details, and don’t ignore “check engine” lights. Doing just these few things will help you to keep your truck longer, enjoy the ride more, and make more money! If you have any performance-related comments or questions, I can be reached at Pittsburgh Power in Saxonburg, PA at (724) 360-4080 or via e-mail at bruce1@pittsburghpower.com.
