Problems are often blamed on electrical issues and bad ECMs, and many people want to fix them over the phone. Yes, bad programs will cause you a loss of power, a loss of fuel mileage, and a lot of aggravation, but wiring issues and sensors can’t be “fixed” (or even properly diagnosed) over the phone. We can often help you over the phone, but not every issue can be talked through and corrected. Sometimes, we just need to get your truck into our shop.
At least once a day, I get a phone call from someone asking, “What kind of truck should I buy?” Being I have never met most of the owner operators I speak to each day, I have to ask questions like: What do you haul? What type of trailer? Where do you live? What speed do you like to drive? What is your preference of trucks and engines? What is your height, weight and age? This is how I get a mental picture of you and your operation. This past winter, I received a phone call from DuWayne Ehrke of Wisconsin, a driver who wanted to get back into trucking. He was asking for help building a high fuel mileage truck. His trailer is a reefer and he runs between Wisconsin and Texas. With his size, I recommended a T600 Kenworth with a DD4 Detroit engine. This engine was produced between 1998 and 2002, so it’s hard to find a cherry one – and, you have to be mechanically-inclined to be able to rebuild a truck with well over a million miles on the odometer.
Taking my advice, DuWayne found a 1998 T600 with 1,300,000 miles on the odometer. Needless to say, the truck needed a lot of TLC and it quickly became a work-in-progress in motion. Before he took his first trip, we recommended him to install: a re-worked ECM, a new crankshaft damper and mercury-filled engine balancer, ported ceramic-coated exhaust manifold, a larger turbo, a FASS fuel system and new fuel lines, a Fleet-Air filter, an OPS By-Pass Oil Filtration System, Micro-Blue wheel bearings, and 2:64 rear gears. DuWayne’s KW is equipped with a 10-speed transmission which I don’t care for (I would prefer a 13- or 18-speed so he could split the gears if need be), but for now we are working with the 10-speed and he is driving it in 9th gear (which is a direct gear). 10th gear is used just for bobtailing or flat-out speeding, which we all need to do on occasion!
The last bit of advice I gave DuWayne was that he should drive between 58 and 64 mph on the level terrain to obtain the best fuel mileage. On his first load, hauling cheese to Texas, there were problems with the ECM, so a stock ECM had to be re-installed. The truck ran fine, obtaining 8.8 mpg going south, and then, coming back north with a load of eggs, he got 8.4 mpg. I think this is great fuel mileage for an old KW with 1.3 million miles on the clock – and its first trip. Once we finally got the Kenworth in our shop a few months later, the electrical engineers were able to diagnose and repair the problems (they found a bad turbo boost sensor and some other wiring issues) and then they re-installed the performance ECM. Now, the only “problem” DuWayne is having is that he is so busy running to Texas and back.
Like I said in the beginning, sometimes it is imperative that we get your truck in our shop to properly diagnose (and correct) wiring and ECM issues. Once Fernando was able to install the performance ECM and give it an additional power upgrade, this is what DuWayne had to say: “The trip to Pittsburgh Power was well worth the time and then some ten-fold. The trip should have been made four months ago before I put the truck on the road. The cost of lost fuel mileage and the aggravation of a poor-running truck made for long days and short nights. Every owner operator knows a good mechanic – they take care of most of the issues you have. Then, you come across a great mechanic, and they fix ALL of the issues. Wow – what a joy to drive again! Listen to the experts. You will not go wrong.”
Before we had computers in trucks, we had to diagnose engine misses with our fingers (see photo), and you can still do it, even with an electronic truck. When the engine is cold, tilt the hood and start it. With both of your hands, using your index fingers, touch the bottom of the exhaust manifold. Starting with cylinders #3 and #4, feel the heat. Then, check cylinders #2 and #5, and then #1 and #6. You must touch them in this order – always 3 and 4 together, then 2 and 5, then 1 and 6. The two center cylinders will get hotter first because they have the most exhaust coming past them, and then #2 and #5 are next. #1 and #6 will take the longest to heat up. The cylinder that stays the coldest the longest, compared to its partner, is the cylinder with the miss.
If you are coming off the highway, the engine will be too hot to touch. Get two rags and a bucket of water and touch the exhaust ports while the engine is running with the wet rags, then watch how the water evaporates. After you touch the exhaust ports several times, the manifold will cool down enough for the cold cylinder to stay wet longer. Then, if you want to see if it’s an injector, switch the injector with another cylinder and see if the miss follows the injector. If not, then there are other reasons why that particular cylinder is not firing. That is the old school way of finding a miss, but it still works today. If you have any performance or efficiency-related comments or questions, I can be reached at Pittsburgh Power in Saxonburg, PA at (724) 360-4080 or via e-mail at bruce@pittsburghpower.com.