I’m writing this simply because at the moment I have nothing better to do. Apparently, I have fixed every car in this county because none of them have come back for any repairs………..that or I scared them away.
I had an epiphany today at lunchtime that suggested to me that I write a little blurb about the differences between flash programmers, modules, and “chips” for our beloved 7.3L Powerstroke diesels. I see the questions that arise occasionally that ask “what is the difference?”, “what one should I use?”, “can I stack them?” etc. Occasionally, there will be confusion present and there may be misnomers, inappropriate usage of the terminology, or just an innocent typo that occurs.

A little background about what is going on in your truck’s computer before I dive into this stuff head-first. There is a component in your truck’s Powertrain Control Module (PCM) that controls every aspect of fuel delivery to make the engine run; when the fuel goes in, how much goes in, etc. In addition to this, it also controls automatic transmission functions like when to shift, how firm to shift, and when to lockup the torque converter. Obviously, there are hundreds more functions, data parameter monitoring, and instant decisions that have to be made during certain operating conditions that the PCM has to continuously perform to make your truck simply START in the morning! The PCM uses sensors to “look” at things like barometric pressure, ambient temperature, engine oil temperature, RPM, accelerator pedal position (APP), manifold absolute pressure (MAP), transmission fluid temperature (TFT), high pressure oil system (HPOP) commanded/desired pressure (IPR/ICP), and others in addition to these ensuring that these sensors give valid data; no open circuits, shorts, high or low resistance, skewed beyond reasonable values, etc.

When the time comes to give your 7.3L a little more (or a lot more) go, you may turn to an aftermarket source to give it that extra bit of zip. Where to go, how to do it, and the processes involved in getting there may present some hurdles. The research involved in getting to where you want to be may seem overwhelming to some. Then there are those folks who jump into something, love the outcome, and then find out that there is something out there that may suit their needs better……and have to spend more money to get what they needed in the first place.

So, what do YOU need? Let’s start with a flash programmer. Popular programmers include the likes of the Edge Evolution, Superchips line of handhelds, and the Diablosport Predator. What do these do? How do they work?

The flash programmer is shipped to you with pre-programmed goodness to replace the existing data in your PCM. The programmer will read your stock file, check for the template code, check to make sure it matches a program loaded in itself, and if so, proceeds to flash (erase) the existing 256K of data on your PCM’s memory and store it to reload later if you desire to return the truck to stock. Once it stores the truck’s original programming, it burns the pre-programmed file into the flash memory chip inside the PCM. These programs are made to please the general public….usually raising transmission line pressure during shifts, raising the fuel rate, and increasing the accelerator pedal position sensitivity. In layman’s terms, the tunes will cause the transmission to shift more firmly, causes the injectors to inject more fuel, and make the “go” pedal more responsive. They do exactly what they are designed to do, but at the expense of being considered “generic” tunes; they please the majority of the customers. On a side note, the handhelds will usually read and clear diagnostic trouble codes. It’s kind of a nice feature for most folks. A drawback to these types of units is the inability to switch power levels “on the fly”. To successfully reprogram your truck’s computer, the engine must be turned off…..since the programmer erases and reprograms the very data that the engine uses to run off of.

The second type of performance-enhancing device is a module (or fueling box). That is exactly what it is. On the 7.3L Powerstroke, there is a sensor called the Injection Control Pressure sensor. What it does is let the PCM know what amount of pressure is present in the high pressure oil system. Without getting technical, the HPOP system is what determines what the actual FUEL INJECTION PRESSURE will be. The ICP sensor is very important because the PCM bases its fueling rate largely on what this sensor is telling it. See where I’m going with this? The module intercepts this pressure sensor signal before it gets to the PCM and changes the value that the PCM “sees”. Fooling the PCM into thinking that the ICP is lower than it really is causes the PCM to make up for the discrepancy and add MORE PRESSURE. In the grand scheme of things, depending on fueling tables and desired ICP, the PCM adds more fuel. Common examples of this type of device are the “Workhorse”, Dr. Performance, and Edge Juice modules. These also work as they are designed….again, for some folks, they work really well. However, similar gains can be had by simply spending a few cents at Radio Shack and picking up a package of resistors and wiring them into the ICP circuit. A major drawback to these is that they add fuel…..they do nothing for the transmission operating parameters. Unfortunately, the stock automatic transmission that shifted lazily and mushy before the addition of the power will usually shift even more lazily because it’s programmed to shift that way. The PCM has no way to know that there is more power going through the transmission; it just thinks that there is a problem with the HPOP system.

The third kind of power-up device, commonly known as a “chip” is used to actually REPLACE the PCM’s existing flash memory with a different memory chip. By using the J3 connector on the back of the PCM, the existing memory chip is essentially bypassed and data from the “chip’s” ……um, chip is used. It is similar in operation to the flash programmer but it doesn’t erase the PCM’s memory. The premise of both flash programming and external “chips” is simple: Change the way the PCM reacts to incoming data from the sensors. Factory programming will react one way to incoming data while the “tuned” programming will react differently or more aggressively to the changes in data from the sensors. It’s that easy. For all intents and purposes, let’s insert some arbitrary numbers and assume that the PCM will add half a millisecond (.5mS) to the fuel injector desired pulsewidth when the accelerator pedal position is changed from ¼ to ½ throttle at 2500 RPM. With aftermarket programming, that number may change to .8mS under the same conditions. That’s part of where the extra fuel comes from.

There are standard “generic” chips out there that are a preset power level. Superchips and Banks are a couple examples of these. Usually, it will be a small box with a flat connector that attaches to the back of the PCM. On the other hand, there are multiple-position chips available out there as well that allow you to change programs on the fly for different situations without shutting off the engine. Simply rotate the **** or push the buttons to toggle between different power levels and features. Some companies make specialty tunes that are designed to work with other modifications you may have such as different injectors or HPOP systems. DP Tuner is a very popular source for these type of enhancements. Be forewarned though, there are a few different individual tuners out there. The best thing you can do is ask other people what they have and what they like vs. what they may have tried before.

A term you may have heard somewhere before is “stacking”. What this refers to is combining two or more power enhancement devices in an attempt to extract more power than either device can create individually. On the 7.3L, this usually results in excessive smoke, high exhaust gas temperatures, and check engine lights….or no gain at all. It is possible to make some components work together, but how well they work together depends on the particular truck. A module (or fueling box) will physically work with a flash programmer or chip. The corrupt signals from the module will cause the aftermarket programming to make more aggressive changes to the data it gets than the factory programming would. Usually, the programmer or chip is commanding increased ICP anyway and the fact that the corrupt data from the module causes the PCM to desire even more ICP causes driveability issues because the factory high pressure oil pump simply cannot keep up with the desired pressure. A flash programmer cannot be stacked with a chip. The chip will override the programmer’s tuning…just like it overrides the factory tuning since the flash programmer’s tuning has taken the place of the factory tuning inside the PCM.

Ok…..enough of this for now. My fingers hurt, your brain is fried, and staring at a computer screen that long isn’t good for your eyes. Get some rest!!

All criticism is greatly appreciated. I don't claim to know it all and any corrections to this would make it better, more informative reading.

 

A+ write up. reps to ya.

 

I'll bet I was the first to rep ya, but did not comment cuz I was still dizzy and blurry eyed. But thank you sir.

 

Very interesting and informative post. A++ I don't even think I could write like that.

 

Terrific write-up. Thanks for the education.

 

Great job.

 

See, that high priced edumacation did pay off. nice write up Cody.

 

Very thorough explanation! Question though- if the PCM uses APP to determine how much fuel to squirt, what is telling the PCM what it needs when the cruise is on?

 

GREAT write up Cody!! A++++ reps on the way!

 

Great write up. Very informative. Thanks

 

Great post! I needed that being fairly new to diesels and having an Edge Juice programmer. All of that stuff was very confusing to me and after reading your post it cleared things up for me.

I have learned a lot just lurking and reading on FTE. Thanks for taking the time to work that post up. You guys do good work !

Bob

 

It knows the speed you desire when you set it. Unlike mechanical pedals that move up and down in cruise control, ours does not. The PCM does not need an electrical signal from the pedal to signal more or less fuel. It does it via electronics based on the speed of the vehicle and load from sensors. It is old tech now but still good stuff. Fly by wire like an F-16.

Unfortunately, fly by wire can cause problems when the pedal assembly goes on the blink. This rascal can be hard to diagnose.

Good write-up Cody.

 

Excellent write up. Reps to ya! Maybe the mods need to add this to the sticky at the top?

 

Great write up Coty, Thanks

 

Brilliant write up Cody. This is one that will be posted many times when someone has a programmer question. Thanks for taking the time to do this.