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Detroit Diesel 60 Series Code 68. No cruise, no jakes

We do a lot of diagnosing at 441 Diesel but that’s not all we do. We do a lot of medium and heavy duty too. This particular truck is a 2005 Freightliner with a Detroit Diesel 60 series. The complaint was a consistent “check engine” light and no jake brake activation/no cruise. I checked it with the Detroit software and saw that the code was for an open circuit for the idle validation switch. The idle validation switch tells the ECM when the accelerator pedal is in the idle position. It is integrated into the accelerator pedal position switch which the previous shop had already replaced. The first thing I did was test the switch. The idle validation switch is just a 2 terminal switch that makes a circuit when the accelerator pedal is released and this completes the circuit sending a ground to the ECM indicating idle. After verifying the switch had 0 resistance when released and inf when pressed I knew the switch was good. The next step was testing the harness. I removed the connector at the ECM and checked continuity from ECM connector to IVS. The wire was definitely broken and showed infinite resistance. We removed the harness and took it apart.

After taking the harness apart we found this broken wire and 4 other wires that were eaten into. This part of the harness was at a sharp bend where a bracket held the harness. We decided to replace the entire vehicle harness because previous shops had done multiple repair to this harness and repinned the data link circuits. This repair shows where the disconnect is for many shops that do not understand wiring completely. If you have any electrical issues or have a truck that no one can fix leave it with 441 Diesel. Thanks guys


Duramax hole in transfer case

Hey guys this is AJ with 441 Diesel. I like to update this blog periodically to keep our customers and friends in the loop with common failures we see. We work on a lot of Duramaxs and a failure we run into a lot is a failure in the NP261XHD and NP263XHD transfer cases. The main issue we see in these cases is that a hole develops in the rear housing and leaks all the fluid out. Once all the fluid has ran out then we see a failure of the shift fork in most cases and this will cause it to drop out of gear going down the road or make a loud grinding noise. The cause of this failure is what we are gonna look at today.

The pump that supplies fluid to these transfer cases rides on the main shaft and the design flaw that causes the hole in the case is the clip pictured below. (courtesy of

This metal clip is designed the push against the pump to prevent the pump from contacting the housing. What happens in theory, as you can see below, is that the clip actually eats into the aluminum case and can wear a tiny hole in it.


The fix for this issue depends on the amount of damage done to the transfer case by the low fluid condition. In many cases the only damage will be to the shift fork. The fork in the picture here is the one that will be damaged in many cases. The plastic lining on the fork falls apart because of the heat and causes a lot of play in the fork area. This allows the collar to move and can cause the transfer case to drop into neutral.


The fix for the “pump rub” issue is a “pump rub repair kit”. These are available through Merchant Automotive online and provides a new design pump with long legs that sit against the housing and eliminate and rubbing issues. You MUST address any damaged components in the transfer case as well as replacing the rear half and installing this new pump. If you are having issues with your transfer case this may be your problem and 441 Diesel has your solution. Thank you for your time, AJ


6.0 Powerstroke Water-in-fuel light

If you own a 6.0 Powerstroke then you’ve probably had the water-in-fuel light come on and many people have learned to live with the light being on all the time. The problem with this is obviously you won’t know when you actually HAVE water in your fuel. Fuel injectors for the 6.0 are around $265 ea. so allowing water to damage them can cost you more than the fix we’re gonna go over today. The water-in-fuel (WIF) sensor on the 6.0 is located in the fuel pump on the driver’s side frame rail. The fuel filter separates the water and channels it down to the drain plug where it can be drained periodically. Unfortunately most people do not drain the water frequently enough so the water coagulates and creates a mucus-like substance that sticks to the sensor. The sensor can be seen in the pic in the lower left corner.

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Most of the time when customers bring this issue to us it is already beyond the point of just draining the housing. We repair this issue by removing the fuel pump from the vehicle. We then remove the filter and this cover that houses the sensor and fuel lines. The pan below is a good example of the amount of crud that normally comes out of a filter housing when the WIF light has been on for an extended amount of time.


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The pic below is the filter housing with the filter removed. After removing the fuel pump cover (manifold) you can flush these contaminants out with some cleaner and maintain a clean housing.

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After removing these components we flush the housing out with cleaner and install a new manifold gasket, fuel filter, and WIF sensor. This ensures a long-lasting repair that will allow you to keep an eye on your fuel quality and make sure to keep your injectors healthy. Thanks guys.


2006 6.0 P2614 P2617 No start

The 6.0 Powerstroke has a tendency to develop electrical issues as it gets more miles on it. The engine wiring harness on the 6.0 has many push-type retainers that keep the wiring harness routed in a specific fit unlike the Duramax which has bolt on clips on the harness. The problem with the 6.0 harness is that many technicians do not bother to connect the wiring harness retainers so the harness sits on top of the intake manifold and can potentially rub through on an intake manifold bolt or stud.

This particular 6.0 Powerstroke experienced just that. It was towed in as a no-start and the customer told me he had parked the truck and went back to crank it and it just turned over but would not start. The most cause of this issue in a 2005-2007 is a possible high pressure oil leak. After connecting the scanner we verified that the high pressure oil pump was putting out correct pressure (550 psi+) to crank but we noticed that there were 2 codes stored in memory. P2614 and P2617 are camshaft and crankshaft position sensor circuit codes. To an inexperienced technician, the repair would possibly involve replacing the cam or crank sensors but in my experiences I’ve only changed 1 cam sensor and 0 crank sensors. They just never go bad. I have however had several trucks with damaged wiring harnesses that would cause a loss of cam and crank signals. The easiest way to test for a wiring harness short is to take a piece of wood and push on the harness on top of the engine near the turbo and near the FICM (fuel injector control module). We wiggled the wires around near the FICM and the truck started right up. As I would massage the harness the truck would randomly stall and surge. I decided to get a better look at the harness and after unplugging it from the FICM we found this. You can see the red and yellow wires rubbed through to the metal wiring. This was intermittently shorting to the intake manifold bolt and causing a stall.


Got an intermittent no start hot or cold?? Check your injector and engine wiring harnesses. Thanks. AJ

7.3l Powerstroke no oil pressure

Powerstroke 7.3l and 6.0l engines use a high pressure oil system to fire the fuel injectors. This system uses engine oil under high pressure combined with voltage from the injector module in order to push the fuel (45-65 psi) out the tip of the injector. This system works great when it has no leaks and allowed for the earlier Powerstrokes to achieve higher injection pressures to atomize the fuel and burn cleaner. The problem with the high pressure oil system stems from it’s tendency to develop leaks and also the fact that the engine can not run without base oil pressure (which can be a benefit being you can never run the engine with no oil). The truck I’m gonna talk about today is a 1997 F-250 that was towed to our shop after a previous shop had built the engine but could not get it running.

When we first started looking at this truck we connected the scanner so we could verify how much injection pressure the ECM was seeing. One thing we noticed immediately was that we had 0 psi of injection control pressure. This is important to note because most systems even with a major leak or failed IPR valve with build SOME injection pressure. Normally if you don’t see any ICP (Injection control pressure) there is a low pressure oil problem. We verified this by checking for oil in the high pressure oil pump reservoir. In the picture before I got off a Ford forum you can see the allen-head plug that you remove and then stick a screwdriver in the hole and oil should be filling it up to around 1/2 inch from the top. On this truck it was completely empty.

HPOP R copy

After seeing the reservoir empty, we cranked on the engine for a few minutes and no oil ever came into the reservoir. This indicated that the low pressure oil pump was not functioning. We decided we needed to tear down the front of the engine to check out the pump.

The LPOP (low pressure oil pump) on a 7.3l Powerstroke sits on the crankshaft behind the harmonic balancer. As the crankshaft turns, the gears turn within themselves and this motion creates a film of oil that then picks up from the oil pump and is distributed throughout the engine. This film of oil that creates suction and pressure is very crucial to the operation of the oil pump.

OilSystemFlowDiagram 7.3

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On the 7.3 Powerstroke this oil pump CAN be installed incorrectly which is what I was thinking when they had just rebuilt the engine and installed a new pump. After removing the oil pump we did in fact verify that it was installed backwards. In the picture above you will note the word damper. This word should face toward the damper or the harmonic balancer and they had installed it facing toward the engine.

When the pump is installed backwards on this engine it “eats” a groove in the timing cover that makes it impossible to build up oil pressure again. In the below picture you will see a sizeable groove worn in the front cover. This kind of damage is irreparable.

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To fix this costly mistake we had to replace the front timing cover and oil pump.

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If you have a Powerstroke that is having trouble building oil pressure the LPOP is a good place to start and if you have any questions call me at 706-677-0060. Thanks, AJ

Isuzu Truck service Athens, Ga

Isuzu trucks are some of the most versatile diesels on the road. They are used commonly in landscaping companies, tow companies, and aftermarket parts suppliers. When running correctly, the Isuzu truck can carry a large load and gets much better fuel economy than the bigger diesels out there. 441 Diesel has recently invested in the IDSS diagnostic software from Isuzu. This allows us to have the capability to program ECMs, perform diagnostics tests, and adjust vehicle top speed without having to send trucks out to Isuzu dealers. If you have any questions for us about our Isuzu capabilities call us at 706-677-0060.


6.0 Powerstroke head gasket repair – What you need to know.

The 6.0 Powerstroke engine that we work on a lot at 441 Diesel. It is probably one of the most notorious diesel engines ever built due to it’s high number of parts failures and the high cost of engine repairs. What we have found from working on them for 10 years is that the 6.0 base engine (block and pistons) is actually a very strong foundation and can last 500k+ miles like its predecessor the 7.3l. The initial problems the 6.0 had were a combination of injector failures, EGR cooler failures, and head gasket failures. The lack of knowledge on the engine and diagnostic methods caused these issues to take excessive amounts of time to repair and also caused repeat failures shortly after. The fuel injectors in the 6.0 have a tendency to heat up at the nozzle and this can cause the nozzle to stick and allow combustion into the fuel system causing the fuel to be pushed out of the cylinder head. Many times the engine would act as if it was running out of fuel and the most common diagnosis would be a bad fuel pump. After checking fuel pressure techs would find excessive pressure and bubbles in the fuel system. After removing glow plugs one at a time the problem cylinder would be isolated and the injector replaced. This was a sizeable learning curve since this issue did not exist with the 7.3l. Below is a pic of bubbles in the fuel system from a bad injector.


Next we will look at EGR cooler failures. To start we should cover exactly what an EGR cooler is. To make the federal mandated emissions for 2003 International added an EGR cooler to the 6.0 Powerstroke. This EGR cooler uses engine coolant to cool a stream of exhaust gas from the engine in order to make the exhaust cool enough to recirculate through the engine when the EGR valve opens. This allows the engine to essentially recycle some of it’s exhaust and cut down on emissions.


When this system is operating correctly it does just as advertised and allows for a cleaner burning engine. When it fails however it can cause much destruction. When the EGR cooler fails it will push coolant out of the exhaust through the turbo and out the tailpipe. In extreme cases, it will pump coolant into the intake locking the engine down and blowing the head gaskets. In the 6.4l Powerstroke this will may times caused a bent connecting rod.

These pictures are off a 2005 6.0 Powerstroke. The pic on the left is the turbo followed by the exhaust manifold and then a view with the cylinder head off. This engine had blown head gaskets from the extreme pressure caused by coolant seeping in on top of the piston while the engine was running.

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There are several options to remedy a bad EGR cooler.

  1. Aftermarket EGR cooler (Bulletproof) This will maintain your emissions and also provide you with a lifetime warranty against further failures.
  2. Factory EGR cooler replacement. This is simply replacing the cooler and since Ford has never overhauled their design will cause further failures down the road unless the oil cooler temperatures are monitored closely and a partially clogged oil cooler replaced immediately. Even then a repeat failure can still occur. ]
  3. EGR delete. EGR delete kits remove the EGR cooler and valve and reroute coolant back in to the engine. This is the only way to ensure no further failures but this method is for off-road use only and is ILLEGAL for on-highway use.

This brings us to the head gasket failures that plague the 6.0 Powerstroke. This issue is the most widely known failure and is the single issue that gives the 6.0 Powerstroke a bad name. We keep records of all repairs at 441 Diesel and after going through our records I can confidently say that we have found that most (75%) of the head gasket repairs we have done on this engine are related to 2 issues.

1. Programming – If you think that Ford left any room for more hp in their engine with the hard parts installed you are mistaken. The big 3 auto manufacturers are in a constant battle to have the most horsepower. What that means is that if they could’ve put 450 hp in the 6.0 they would have. Most programmers have the capability to add upwards of 120 hp to the 6.0. This means that the 230 hp that International built the engine to withstand is essentially expected to withstand double the power. If you want to add power to your 6.0 plan on installing ARP studs and o-ringed heads. It’s the only way to make it last.

2. Bad EGR cooler – In the pictures above you can see the amount of coolant an EGR cooler can pump into the intake. The piston of the engine is already pushing a lot of pressure through the exhaust valve ports so if you add a liquid to the mix you can expect a gasket failure.

I will say that the Ford head bolt design is inferior to every other engine out there and I’m not giving them a pass I’m just making the point that only 1/4 of our head gasket repairs are on stock engines with good EGR coolers. The 6.0 only has 10 big head bolts and they are torque-to-yield so they are known to stretch under extreme load. With that being said we have 10+ International trucks that we service and we have had 0 head gasket failures on these engines because they are 215-230 hp and they are maintained meticulously.

¬†I’ve got blown head gaskets! What next?

441 Diesel has the fix that lasts. We use ARP studs, Ford head gaskets, and o-ringed cylinder heads to ensure that you never have to worry about your head gaskets again. ARP studs are made for racing and are much stronger than the factory bolts preventing stretching. Ford head gaskets are the best out there right now and if you get a quote from anyone using black onyx gaskets please RUN. Our machine shop will rebuild your heads to factory specs and then install o-rings that will bite into the head gasket ensuring a permanent seal that gives you further protection at extreme boost levels. We also replace your oil cooler, clean your turbo vanes, and reseal your high pressure oil pump (upgrade STC fitting if applicable).

This is a shot of a set of rebuilt heads before installation. You can see the steel O-rings cut into the head.


If you have a 6.0 and want a quote on our head gasket repair or want to ask any questions don’t hesitate to call. Thanks for taking the time to read. AJ



Fast Diagnostics

Our goal is to get you the information about your possible repairs quickly. We understand¬†our customers don’t like to be left waiting on the details of their repair. Many of our happy clients brought their vehicles to us after waiting a week or more just for a diagnosis at the last shop. That’s why we offer same-day diagnostic guarantee when the vehicle is at our shop no later than 8:30am Monday-Friday. 441 Diesel offers dealer-level diagnostics at a fraction of the price. To schedule an appointment call us at 706-677-0060


441 Diesel is one of the select few shops in Northeast Ga. that has access to the IDSS Isuzu diagnostic software. This allows us the capability to correctly diagnose any heavy-duty Isuzu truck the first time. Isuzu makes great quality trucks but many shops around have not invested in dealer-level diagnostic software to be able to fix these truck quickly and correctly. We have ECM programming capability as well as access to the entire Isuzu parts catalog for OEM replacement parts (Genuine Izuzu) at wholesale pricing. Many fleets take their trucks to Atlanta just to be able to have their engine codes read. Now, they don’t have to!

441 Diesel offers 30-35% cheaper labor rates than shops in the Greater Atlanta area and we provide very quick turnaround time.

If you have an Isuzu truck and need any repairs call AJ at 706-677-0060.

Fleet Services

441 Diesel offers a variety of fleet services such as: DOT inspections, preventative maintenance, light system repair, and electrical repair. We service several fleets of emergency vehicles and we offer access to many aftermarket parts suppliers that other shops just don’t have access to. We also service propane trucks and we have access to specific lighting systems and safety equipment that is required for these vehicles. If you have a fleet and have any questions please do not hesitate to call us and ask about our fleet service contracts.