DT MaxxForce Diesel Engine Will Not Run


There are 2 valuable tools that come to mind when working on your typical diesel engine … engine diagnostic software and your brain. There are so many areas that need to be checked when the engine will not start. Checking the source is the number one step to carry out. This means checking the fuel tank for diesel. Is there any in there? OK a no brainer but let me tell you this has baffled many mechanics myself included. If the operator tells me he just filled up with diesel I will believe him and carry out the diagnostics without thinking about the fuel tank.

Then after a couple of hours you start thinking backwards. My question would be why is there no fuel flowing through the lines. Once I realized the fuel tank was empty in this instance the lesson learned was ingrained in my mind. From that day I have never skipped the fuel level check regardless of what anyone says. The time wasted on this job was frustrating so experience has proven to be helpful over the years. So you might have heard all it takes for a diesel to run is air and fuel. That is very true and in this case the exhaust was restricted causing engine shutdown.

I’ve seen this happen before because of the constant operation of the exhaust brake air cylinder it eventually breaks down from excessive heat and fatigue. The way I went about finding an engine issue with no codes and good pressures is basic. Check the fuel then open the hood. Use your eyeballs and start scoping anything that looks unusual. Luckily the seized exhaust brake cylinder was in the open and easy to spot.

Finding an external problem is a huge bonus. This is going to be a quick fix compared to digging in to the top end and spending hours on a repair. Today was my lucky day and I would like to have more of them ha ha. It’s interesting and rewarding to troubleshoot and repair a problem. The challenge is constant with any diesel engine but the diagnostic software is extremely valuable with ways to view all the necessary pressure readings like turbo boost, ICP (injector control pressure) and fuel pressure.

I was using NED (Navistar Diagnostic Software) and I recommend this to anybody serious about saving time and money. The yearly subscription is well worth it since we have 18 MaxxForce diesel engines in our fleet. We can scan our diesel engines with confidence.