I posted this on an existing thread, but I'm thinking it should have its own thread.
***Tech Alert***
One of the biggest fears for the stock ECM is if you should get into the bypass (limp) mode using big injectors; you'd wash down the cylinder walls and hurt the engine in no time.
The Calpack chip is nothing more than a series of resistors in an unusual matrix. Each value gives the ECM a "starting point" for each closed loop sensor which should allow the engine to run without closed-loop sensor activity. There is a resistance value that's somewhat matched to your stock injectors (28lb). If you can change that resistor value to one that's more appropriate to your larger injectors, your bypass mode will be much safer for your engine should your PROM chip fail. It would be a much safer environment for your engine.
So.
Some years ago, I decoded the chip. Various resistance values input an equivalent value to the processor to "fake" the existence of sensors. One of these resistance values controls pulse width on your injectors - and your challenge is to find it and modify it. You'd have to access the pins of the chip and externally modify its value with resistors or trimpots. The ECM schematics are out there and a bit of research would get you to the correct resistor. A bit of experimentation will allow you to fine-tune the injector pulse and trim it to your setup. Richard C, if I'm not mistaken, you should have a benchtop rig to analyze ECM's, which would be a great starting point.
Take a look at the decoded chip layout here along with an explanation:
http://www.installationinstructions.com/FYI/16036503_calpak_tech.pdf
Techie geeks, have at it! If you decide to take on this project, all I ask is that you share your research, as I am doing, with the community.
***Tech Alert***
One of the biggest fears for the stock ECM is if you should get into the bypass (limp) mode using big injectors; you'd wash down the cylinder walls and hurt the engine in no time.
The Calpack chip is nothing more than a series of resistors in an unusual matrix. Each value gives the ECM a "starting point" for each closed loop sensor which should allow the engine to run without closed-loop sensor activity. There is a resistance value that's somewhat matched to your stock injectors (28lb). If you can change that resistor value to one that's more appropriate to your larger injectors, your bypass mode will be much safer for your engine should your PROM chip fail. It would be a much safer environment for your engine.
So.
Some years ago, I decoded the chip. Various resistance values input an equivalent value to the processor to "fake" the existence of sensors. One of these resistance values controls pulse width on your injectors - and your challenge is to find it and modify it. You'd have to access the pins of the chip and externally modify its value with resistors or trimpots. The ECM schematics are out there and a bit of research would get you to the correct resistor. A bit of experimentation will allow you to fine-tune the injector pulse and trim it to your setup. Richard C, if I'm not mistaken, you should have a benchtop rig to analyze ECM's, which would be a great starting point.
Take a look at the decoded chip layout here along with an explanation:
http://www.installationinstructions.com/FYI/16036503_calpak_tech.pdf
Techie geeks, have at it! If you decide to take on this project, all I ask is that you share your research, as I am doing, with the community.
