July
2011
"STORIES"

Last month I wrote about Carl Kellner from Buffalo N.Y. and his 379 Pete powered by a 6NZ Cat getting 7.5 mpg traveling at an average speed of 56 mph.  Since last month Carl has purchased our ported and coated exhaust manifold, our performance Cat turbo, a turbo blanket, header wrap for the exhaust pipe, and the Pittsburgh Powerbox.  By Memorial Day weekend Carl had everything installed except the Pittsburgh Powerbox. Shortly afterwards I got a phone call from Carl during his first test drive. While bobtailing he stood on the throttle and told me the drive tires were leaving marks in the asphalt and the response was unbelievable!  It's always a pleasure to hear excitement in the voice of a 53 year-old gear head.  Anytime you try to improve the fuel mileage on a truck that is already producing 7.5 mpg you have to realize that your fuel mileage gains get smaller and harder to get.  Despite Carl's already skillful driving and his truck's remarkable fuel efficiency, I'm happy to report that Carl gained an additional four to sixth tenths within the first week with his new upgrades.  Eight mpg out of a 379 pulling a company trailer and he hasn’t even installed the Pittsburgh Powerbox or the 2:64 rear gears yet.  Carl has a very consistent run with minimal variables. He runs the same route every week, fuels up at the same fuel pumps each week and parks at the same locations each week.  We expect Carl will produce some very accurate fuel mileage reports. 

Bruce and Carl Kellner

For years I have wanted to develop a good way to connect the back of the sleeper with the trailer to eliminate crosswinds from getting caught in front of the trailer and causing excessive drag.  Finding the time to develop things like this is difficult for me. Often I depend on the ingenuity of owner-operators as over the years they have taught me much.  Last month we had the privilege of meeting another creative thinking owner-operator by the name of Tim Kenevan.  Tim needed a truck in a hurry and let a truck salesmen sell him a new International with the new Max Force engine.  Tilting the hood you couldn't even see an engine because of all of the BS hanging on it.  This fifteen-month old truck had already spent three months in the shop.   That's one day in the shop for every five days on the road.  Don't laugh; there are many other newer engines ridden with EGR, DPF and SCR problems that are spending just as much time in the shop. I understand this thing makes so much heat from its aggressive EGR system that it has 4 coolers somewhere in the engine compartment.  Does it get the fuel mileage the salesman promised? Nope… sorry, there is none to be had here. However his invention does help this truck make fuel better fuel mileage.  Tim is a thinker. He used to be a nuclear power engineer in the Navy. His love of trucking proved too strong to resist and after his Naval career he purchased his first truck in 1977.  His invention "The Cross Wind Blocker" is the result of a joint effort from this retired nuclear engineer and a project engineer from John Deere.  Needless to say this product was very well engineered and is manufactured of rotational molded plastic.  The Cross Wind Blocker panels are mounted with stainless steel and aluminum mounting hardware.  It's a fully adjustable system and can be removed or repositioned on the trailer with the pull of one pin per panel.  These panels are hardly noticeable on Tim's truck. In fact it looks good and with gains of 1/2 mpg or more it looks even better.  Joe Lambright, who is leased to Long Hall Trucking, owns a W900-L Kenworth powered by a C-16 600 Cat and pulls a Benson flatbed with a roll tarp and has a 60" gap between the front of the trailer and the back of the bunk.  Once Joe installed the Cross Wind Blocker he has gained over 1 mpg.  Keep in mind that wind can only jump a 36" gap between the back of the bunk and the front of the trailer so with a 60" gap he was pulling a lot of wind.  The Cross Wind Blocker is adjustable and can be adjusted to fit any truck with the pull of just one pin per panel.  So even if you pull a company trailer that has a Cross Wind Blocker installed you will be able to adjust it to your truck in about 90 seconds.  Pittsburgh Power is the master distributor of the Cross Wind Blocker so you can call us with your questions or call Tim the inventor at 509-675-8244.  The Cross Wind Blocker starts at $4300.00 for small trailers and $4800.00 for the largest of trailers. Just think if we could get Carl Kellner to pull trailers with the Cross Wind Blocker installed. He would be getting 8.8 mpg from his 379 Pete.

Now onto to Fernando, "Mr. ECM," for what's new with ECM calibrations and truck wiring problems:      

Fernando "Mr. ECM" DeMoura.

Last month I wrote about a W900 with multiple wiring problems that even Detroit Diesel and Kenworth gave up on. You may recall I wrote about this truck having a throttle positioning circuit problem and how we cured that. Today I will talk about how we discovered and fixed the Jake and engine fan problems in the wiring harnesses. For those of you who didn't read last month's article, this 99' W900 would lose its Jakes when the engine fan would activate. Both of these events were intermittent.

The manual fan switch of this W900 was functional but the DDEC III ECM couldn't detect the fan override on its digital programmed input. To further complicate this problem every once in a while when the engine fan clutch was engaged, the Jake brakes would no longer activate. Somehow these two circuits were interacting with one another and the engine computer wasn't showing any clues as to why. This interaction between the two circuits could only happen in three different places in the truck's electrical system. The most probable location was the primary OEM harness that linked the DDEC III controller to the firewall connectors. This harness supplies the input and output signals for both the Jake and the engine fan. This is the first harness we needed to remove from the truck and inspect. The second possibility was the Jake and fan override input signals could have been interfering with one another in the dashboard harnesses. Dashboard harnesses are not subjected to as much heat, corrosive substances, and vibration as the harnesses on the other side of the fire wall so odds are better that the problem is in the OEM harness. As it turned out both harnesses were responsible but I will get into that later. Thirdly the DDEC III ECM itself could have had an internal electrical problem. Many people like to blame programming for this sort of thing. What these people need to realize is how easy it is for an electrical problem to give the programming bad information.  ECM electrical and programming faults are not nearly as common as people tend to believe. To date I have only seen a handful of engine controllers cause problems like this. Eliminating this as a possibility is relatively easy if you have test ECMs sitting around so even though it's the least likely cause, this is the first thing we eliminated as a possibility. With a test ECM installed we verified that the problem still persisted. If the problem was only an intermittent Jake issue we would be taking a hard look at the sensor and injector harnesses but because it is directly related to the engine fan we can eliminate those as potential problem areas at this point. Before removing the OEM harness from the truck there was one other problem I wanted to investigate.

The laptop was telling me another circuit related to the engine fan known as the auxiliary fan input control (connected to the air conditioning pressure switch) was receiving a constant ground regardless of the condition of the air conditioning. In order to test this circuit I needed to have the OEM harness on the truck. With everything still plugged in I was getting a ground signal on the auxiliary fan control input. After I unplugged the auxiliary fan control input I was still getting a ground on the laptop. I then removed all the OEM harness ground cables and unplugged all connections except the ECM connector and ECM power. I also ran jumper wires for the firewall ignition and communication connectors. I checked the laptop and still had a ground. I checked resistance between the auxiliary fan control input and the frame and got a resistance of infinity. This wasn’t possible. I thought for a moment that my meter was faulty but after testing it I found out that it wasn't. When things like this happen it's easy to get frustrated and give up. Getting frustrated can kill a technician's productivity and sprit. A tech has to take a step back and look at the facts and keep asking questions.

I then switched my meter to measure voltage and got 12 volts in a circuit that should only have given me 5.  I've never seen an ECM supply 12 volts for a sensor application. That’s when I knew the 12 volts I was measuring from the ECM auxiliary fan control wasn’t coming from the ECM. To verify this I disconnected the OEM connector of the ECMAND still got 12 volts.

There had to be some other 12-volt circuit shorting to the auxiliary fan control. At this point there was nothing left to do but remove the OEM harness from the truck and gut it like a fish.

Once the OEM harness was off the truck I traced out the damaged circuits and found out what was causing some of these problems.

As you can see in this photo the auxiliary fan control wire had rubbed though and welded itself to the 12-volt ignition wire. The DDEC III ECM was interpreting this voltage difference between its own 5-volt supply and the 12-volt ignition wire voltage as a ground. I had been chasing a ghost. I was looking for a ground that wasn’t there. The auxiliary fan control didn't have a ground, it had a short but the ECM couldn't tell the difference. Since the owner bought this truck the ECM had to be replaced twice. 12 volts being crammed down the 5-volt throat of this DDEC III probably had something to do with that. After the OEM harness was repaired and reinstalled on the truck I moved on to the dash.

To make a long story short I discovered a bad ground that had about a volt and a half relative to the frame and battery ground. Grounding the dash ground to the frame wasn't working because something was wired in series into the ground. Whatever this device was would energize the dash grounds drop the electro potential difference by 1.5 volts. The ECM had a separate ground so it only saw a 3.5-volt difference instead of a 5-volt difference through its digital input circuits. The ECM then assumed the circuit has been opened even though the operator had attempted to ground the circuit to the faulty ground through the dash switch.  This ended up being another case where the engine computer was being fooled by bad information that it was receiving though the wiring harness. Once I realized what was going on found myself at a crossroads. The first thing I could do is try to figure out what circuit was energizing the dash ground and isolate it. In order to find this faulty circuit I might have had to completely disconnect every switch and gauge in the dashboard and pull every fuse and relay in the power distribution box. Or… I could just wire in my own grounds that I knew were good and that is just what I did. I could tell as soon as I hooked up the laptop that I had fixed the problem. After repairing the OEM harness and running new grounds for the dash the Jake and manual fan switch were working flawlessly.

Next month I will conclude the story on this truck and talk about how we made a new engine fan solenoid circuit.

Written by; Bruce Mallinson, Fernando DeMoura & Eric Moser; Pittsburgh Power Inc.; 3600 S. Noah Dr.; Saxonburg, Pa. 16056. Phone 724-360-4080.