[Turbodude]

Hey guys. Ive noticed that a lot of guys on here, especially those who are new to PSD's, are asking about wierd sounds and hesitations from their trucks when its cold out. Im going to answer those questions before they are asked. Now that it has gotten cold out there are a few things your truck will automatically do on its own to conpensate for this. The first and probably main thing the truck will do is activate the Exhaust Back Pressure Valve. I know that a lot of you guys on here have disengaged this valve due to many personal reasons so if you are one of these people then pay no mind. The EBPV is a butterfly valve that International has incorporated into your engines exhaust system. It is located directly after the Turbo Turbine outlet and before the downpipe connection. When Certain Criteria are met, the computer closes this valve which restricts exhaust flow. This in turn creates hefty back pressure and causes the truck to work harder to force the gases out of the pipe. Because of this the truck warms up faster and you will have heat in the cab sooner. When this valve is Engaged the truck will hesitate/bog down as the vavle is engaged, after all this valve works like an exhaust break and reduces your trucks ability to pass the exhaust gas. If you give the truck throttle or maintain constant throttle the truck will eventually come back to life. Also you will hear a significant change in your exhaust's sound...it will sound like loud hissing and you will not notice any turbo whine. If your truck has an aftermarket exhaust system on it this sound will be much more pronounced. This is all very normal and will not hurt your engine, after all International put it there for a reason.

The next thing your truck will most likely do is revert to a high idle setting...this is where your truck will actually rev itself to around 1000 RPMs. 94-97 guys this doesn't happen so often but it will do it...YOu 99+ guys it will do it in a heartbeat...don't be alarmed it is normal and will not hurt your engine.

Engines always get worse fuel mileage in the winter...its a fact that we all have to deal with. Some reasons for this decreased mileage include: extended warm up periods...if you let your truck idle for a long time to get it to warm up then you will get worse mileage...after all that is 0 miles to the gallon. 7.3's like a bit longer of a warm up time because they are old and stubborn. Thats not to say that you need to have them idling for an hour every morning but a good 10 or 15 minutes is plenty, remember there is that EBPV that helps warm the truck up to while you are driving it. 6.0 owners your trucks are designed for people who don't know how to drive a diesel...so International has built it so that you can drive on it with minimal warm up time. Thats not to say start it and go i would recommend 10 to 15 minutes as well. Another cause for poor fuel mileage is that EBPV. It restricts exhaust flow and therefore causes your engine to work harder. This equals more fuel dumped into the engine. Tire pressure is another big thing. People don't want to check their tire pressure when its cold out. Make sure you have proper tire pressure. Another big factor that people don't think about to often is that the various oils (Transmission, Differentials and powersteering and even engine oil) are cold and have a much lower viscosity. This means that because the oils are cold they have a much higher resistance to flow, and until they have warmed up they cause your engine to work harder to get them moving....This is especially noticeable in Powersteering (loud whining sound) and Automatic Transmissions in thier elevated shift points and hesitations to shift when placing the transmission into drive or reverse. Another real biggy is if you have 4 wheel drive and drive around in 4x4. Many people who have Manual locking hubs leave them in the locked position when they are driving in snowy areas so that all they have to do in a bind is shift the transfercase. This is fine and really doesn't hurt anything other than your fuel mileage. When you have your hubs locked or even drive around in 4x4 you have a whole set of new moving parts...YOur engine now has to work to spin a new set of gears in your transfercase as well as your front differential. It also is turning your front tires. This increased load on your engine equals more fuel consuption.

Some things you can do to aid your truck in this cold whether include several things one of which are block heaters. A block heater is a heating element that is installed into one of the engine block freeze plugs. When this device is plugged into an outlet it heats the engine coolant as well as the engine oil to a degree. These come in very handy as they ease the difficultly for your engine to start as well as the time it takes for you to have heat in the cab. Another big thing is don't jump in your truck start it and then crank the heat...You will only get cold air and are slowing the process of heating up the truck by helping the heat escape from the engine compartment. Start the truck and go back inside and have a cup of Joe...after that 10-15 minutes has passed go out side and then turn the heat on as you get ready to leave for work. Alot of Guys like to put a piece of cardboard infront of their radiator. This Helps heat the truck up but i must warn you it can lead to overheating.

Take care of your truck and it will take care of you. Im out of ideas so if anyone has anymore feel free to add. I just thought that i would help out anybody who has questions about why their truck is acting funny so that they didn't have to post a thread and then wait for answers.