I've only been on this site for a few days, and I'm surprised to see other's thinking about stuff that I think about. I see some people beginning to experiment with DIY fuel injection. Does anyone have any stories to share? Hints? Tips? How do you tune the injection? I know there are some good DIY kits. Anyone use them?

Thanks

Do you want to know about theory, or about the actual hardware? Are you talking fuel, spark, or both?

I'm not certain about a specific place to learn about theory. I get it mostly from working with aftermarket and modified OEM ECU's and a load of technical magazines and some books.

Hardware is generally not all that complex unless you want to do fancy stuff like ion sensing.

You can also check out the other ECU projects, like Megasquirt and all it's variants.

It was at least 15 yrs ago that I looked at converting a GM V-6 to throttle body injection (from carburetor). Holley made a kit. I'd like to think that considerable advances have been made since.

I've found you can do multipoint injection with a basic 8bit uC, but doing full sequential injection with ignition is really pushing an 8bit. You can do it if you use one of those crazy hi tooth count trigger wheels, like a motronic wheel.

Closed loop control with an O2 sensor is not that difficult. Seriously you need the theory, because there's a lot of little stuff that's implemented to take care of how fast or slow the sensors are, environmental correction, and loads of details. You can make a really basic multipoint injection controller without too much difficulty, even with steady throttle closed loop, but you start to get fancy and there's a bunch of things you need to know about.

Originally Posted by BrownOut

DirtyLube: I've been all over the Mega-Squirt site. In fact, that would be the product I would choose for any project I do. I actually have the theroy, at lest the 20,000 foot view. I've never looked at and code... not ever sure I want to. Basically I would like a conversion that is as painless as possible. My hope was that someone has already been throught the process and can give me an idea of how big of a pain in the ASP it is

I think megasquirt has a yahoo groups mailing list. I would join that and look through the archives. There's thousands of MS installs. I know you'll get whatever answers you need there. Personally I've never used MS. The later versions look pretty advanced, though.

I've done a few systems, but I've never updated a previously carbed engine to EFI.

I've done a few systems, but I've never updated a previously carbed engine to EFI

Sorry if I gave you that impression. The Jeep isn't that old. I only wanted a system that is 'tunable.' I know there are lots of 'add-ons' to tune factory systems, but I thought it would be better to have one that is tunable right out of the box.

I think you'll find what you are looking for on the mailing list then. There are a lot of vehicles represented there. I've done basic testing on a car, just by unplugging the ECU and plugging individual wires into the wiring harness for testing. It's simple and means you aren't committed to anything if it doesn't work.

I'm also not very knowledgeable with domestics in general, but I know there are some of the OEM ECU's that are reprogrammable. I'm not certain if you've looked into that option. It most likely wont support going forced induction, though.

From what I have read ans understand of EFI is there has to be some reasonable fuel mapping capacity in order to get the best overall response and efficiency out of a system.
I would go with the Mega Squirt or something similar. Its proven technology and likely far more user friendly Than home made!
After market is a great way to go for any updates and being fully custom you can get away from the emissions garbage programming and actually set your self up to get power and fuel mileage at the same time!