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Old 12-14-2011, 09:10 AM
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I am not sure what you are looking for, but I'll answer some....maybe not how you want

To run with a larger cam is pretty simple, but can not be properly done with out "chip" or eprom tuning. The ECM looks at several variables to decide fuel delivery and timing control. However, the most important things it uses are the fuel and timing tables which reside in the software. These tables, fixed numbers such as injector flow rate, along with external input from various sensors, feed into an algorithm to control injector dwell time(how long they are open). So, forget throwing in fat injectors with a cam without retuning. Engine temperature, intake air temperature, manifold pressure, and/or manifold flow sensors, and Oxygen sensors are all used in conjuction with these tables to calculate needed fuel. The fuel pulses are timed and adjusted in microseconds through complex algorithms that you can not change in most cases. Some factors can be scaled, but the main tuning is done in the tables.

Timing is very similar to fuel....

So, it is just about impossible to do anything other than minor changes and have favorable results.

With a turbo setup, it changes ALOT. Most factory ECU's are not really even capable unless you want to learn how to program at the machine level. There are some exceptions, but as a rule it will not work right if it was not turbocharged to begin with unless you are an expert programmer or want to pay one. When I did my turbo setup it took close to a year to build, program and tune the EFI. I was a controls engineer at the time so I thought I was well equiped...I was wrong and the learning curve was painful.

If you try to halfway tune it with some kind of "tricking" of the ECM you will end up with a pig that runs right about half of the time and you completely loose the benifits of having EFI. At that point you might as well carb it and be done. It will run better.

Sorry, but EFI is not a little puddle you stick a toe in. If you are gonna dabble, you are gonna get wet. So, either deal with it in factory trim, learn to tune it, or pay someone else to.

Last edited by TurboS10; 12-14-2011 at 09:28 AM.
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