88b16civic

I am starting to design a water injection system for a turboed b16.
I wanted to meter the water mix in relation to the charge temperature, relitive humidity and mass flowrate and then use a injector(s) to atomize the water mix.

I wanted to write a routine that will inject the appropriate water to air ratio based on the above conditions and this info http://not2fast.wryday.com/thermo/water_injection/

I am going to use water compatible injectors

I was thinking of using a PM6 chipped with turbo edit to drive the water injector(s). I wanted it to read RPMs and the input map voltage and only inject based on the tables (no O2 sensor, temp compensation, or TPS enrichment). My question is, is it possible to fool the rest of the inputs so that the ECU will not go into limp mode and only drive the injector(s) based on the table.

I will be incorporating a development board to input the charge temp, relative humidity, and MAP to decide how much water mix the charge can vaporize and then output it to the MAP input on the ECU. The injection duration will then be decided with he fuel tables. The dev board can also simulate voltage inputs if needed. Hope this makes sense.

What do I need to do so that it will not throw codes for the EACV, ignition, etc.

Thanks in advance.

Chris Harris

Me not being in on the ECU coding, here's my guess.

If you have a separate board, that could accept an external signal for when to activate, you could use the PS9 ECU and use the 1 wire vtec for 1 wire water injection.

However, you said you had a b16, but you also said you were using a PM6 so I figure you have another way to activate VTEC?

However...with my limited understanding of water injection, I would think you would want to inject based on the MAP sensor, and not so much RPMs. So if your board could recognize what voltage the MAP sensor was feeding back to the ECU, it could inject by tapping into that ECU input and using the MAP voltage reference to drive your water injector.

I dont believe any codes with throw for ignition or EACV based on water injection alone using the current development code.

88b16civic

Sorry I wasn't too clear, Im going to use a PS9 for engine management and a separate PM6 just to run the water injectors.

The development board will take inputs from RPM, Map, a thermocouple before the injection, and a relative humidity meter. From this data it will decide how much water per unit of air to inject. I will output this to the MAP input on the PM6. The PM6 will then do a lookup on this voltage and RPM and then inject the appropriate amount of water mix. Since the MAP voltage input is the dev board output I was going to make the far left column fully saturated cold air to the far right column of fully dry hot air.

Im just seeing if I can use an extra PM6 instead of going with mega-squirt or something to drive the water injectors.

Hope this helps

Chris Harris

Sounds ok to me...there are ways to disable the CEL codes in the NG48 code by turning on/off option bits.

Here is a thread and some comments in it by l3st4rd:

http://forum.pgmfi.org/viewtopic.php...=asc&start=105

88b16civic

From the post it sounds like it only tells the ECU to not flash a code but it knows about the sensors and still compensates accordingly

Is there a post that lists the ECU input conditions from the sensor so that it will not flip out. ie. XX resistance over wires X and X for the EACV.

Chris Harris

Try the WIKI.

But other than that I am probably no help.

try sending blundar an email...hopefully he wont be too busy to respond.

a post like this might get more positive attention on PGMFI as well

88b16civic

Thanks for everything, Ill try to keep everyone updated. Your right this is probably too nerdy for HMT, only you and a few others know the interworkings well enough to simulate the entire ECU besides the RPM and MAP.

When I get it running right, I might do a write up and post the dev board code

Chris Harris

That would be sweet...water injection is one of those things I think a lot more people would love to know about.