I suppose this could be a general diesel question, but since it pertains to the manipulation of sensor signals that are in third generations, I've posted this here.

I need some help understanding some things that a couple of low HP boxes are doing, like the XZT or EZ for example. Neither, as far as I can determine, have a digital link to the ECM. So, there only seems to be analog signal going back and forth between box and ECM, even if the boxes have processor capabilities. I understand, I think, why the MAP sensor signal is intercepted and reconfigured for the ECM. But, I don't know what the fuel pressure sensor plug does, or what exactly it goes to. Is there only a sensor, or is there a senser/control device all in that plug? If those two boxes are controlling extra fueling, by pressure, timing or pulse width, how is this being done? Does the MAP signal have anything to do with this, and therefore the ECM is reacting to the reconfigured MAP signal and adjusting fueling?

I like to know how things work, and my brain hasn't figured this all out yet.

 

Pressure boxes more or less fools the ECM. The box fools the ECM to the actually MAP and rail pressure sensors readings. The MAP is for for determining the boost and at what level, it fools the ECM into thinking the boost is lower than it actually is. Keeps from setting the overboost code. Same goes for the rail pressure, the box fools the ECM with a lower pressure reading so the ECM makes the CP3 injector pump output more fuel (higher pressure than normal because of the mapped algorithm and from the APPS) for more power.

MikeyB

 

The MAP is used for timing, pulse width, pressure and how much fuel the truck will deliver in all. There is a lot going on with that little sensor if you know what you are doing.

The fuel rail does control fuel rail pressure, but it also has an effect on the fuel duration as well. The ECM likes the duration and pressure to match up a certain way.


Oh and yes the MAP sensor is capped to prevent an overboost condition.

That is about all you are going to get out of me. How much, when, where, why and all those other questions you are asking yourself is proprietary and I will probably have a different answer than Edge.

Quad

 

On your adjustable module, what is the max rail pressure that it delivers? The reason I ask is because I have read alot of posts on adding fuel pressure and it causing problems. That is why I am looking into the edge juice it is a adjustable box just like your except is all timing and duration it doesn't add any pressure. Are you looking into a timing duration box only or with whatever box you put out are you gonna continue to raise rail pressure? Thanks for the info. Also do you have the adaptor ready for the juice to work with the commander? Thanks.......

 

Well, on the "race" module we will get into the 26.5K range and it might spike up and down a few hundred psi from there? The CP3 pulses really bad so a dead accurate reading is hard to come by. Also it seems like one truck will go to 26K and another might hit 26.6K. I guess it depends on how strong the pump is?

You see a lot of post hearing that pressure is bad, BUT how many posts do you read where people stack pressure without any issues? It is easy to say that pressure kills injectors, and in some rare cases that may be true. However I can tell you from experience that stretching the duration also puts some stress on the injector as well.

There are stock trucks with injector failures as well, I do not think that you could blame them on pressure can you?

We have a couple of things in the works. Very cool things. I will tell you that most of our products will have the ability to alter the rail pressure. Some of them may have the ability to turn this off if you wanted a timing/duration module only.

The Juice part is not 100% finished, but a bunch of the others are. The Juice and TST will take slightly longer because they are more complex and we are trying to keep several of the features available on them with our monitor. Like on the Juice we are working on being able to give you all 5 power levels plus the low boost fueling options.


Quad

 

At what pressure does a properly functioning relief valve bleed off the pressure?

 

Thanks for the quick reply Quad....

 

Thank you for that info. I just like figuring things out. And, if I go to light HP box, I want to have an idea of what it is doing and why. Nothing like jumping on the bandwagon not knowing where it's headed.

Someone posted a link to a good article about pressure. I don't remember the number, but somewhere not far above 26,000 I think was the setting of the relief valve. I may be way off. My concern is only this: running above stock is OK with me if the maximum performance-box pressure is designed not to operate above the relief valve. My understanding is the relief is a safety; however, as flukes can happen, and any mechanical or electronic device's production line is not 100 percent flawless, in the event the valve fails, I've got problems. In other words, I'd rather not hit the relief limit consistently, using it as a way to control the top of the performance pressure perhaps promoting premature cycle-failure.

I'll see if I can find it.

 

Above 185,000 kpa or 26,831 psi.


No more, No less.

 

Never mind. There's your answer.

Can I ask this without you devulging your secrets. Maybe the word "how" isn't what I'm looking for, but how does your XZT box, or any of them for that matter, know to keep the pressure within reason, under that limit? 26,500 for the race box seems close (then again, I have to assume you guys know your stuf)f. Or, maybe I should ask: Does your box "know" enough to keep the pressure under that number, or not over-modify a sensor signal so the ECM keeps the presure under that number- which ever the case may be?