|View single post by rossjfox|
|Posted: 06-16-2012 04:54 pm||
At the Jensen East 2012 Steve Duchene gave a well received presentation on crank fired ignition and fuel injection of the Jensen Healey. This prompted much conversation and exploration of the possibilities. And for me personally, many questions as to the car I am building, and prompts for information about it…
I too have been building a fuel injected Jensen Healey. My car is not different from Steve’s in theory, and in fact there are many steps I took to achieve a running car which I could not have done without Steve’s help and guidance. However, my car is a bit different in execution, using all new components which can be purchased and replaced easily.
First a word of background. The project I am working on was started about 15yrs ago by the car’s owner (I’m simply acting as the mechanic trying to finish the project). At that time, the engine lost compression and a decision was made to rebuild the engine to 2.2 liter specification and hot 104/107 cams. In an effort to improve drivability given the aggressive set up, it was decided to pursue fuel injection, and by default, crank fired ignition. (You can have crank fired ignition without injection, but not the other way around.) All the components were purchased, the engine rebuild completed, and then the car sat in the garage until this past winter when I took possession of the car and began rebuilding.
Here’s what we’re using and what’s been done. This is not a plug and play project. While the components are available off the shelf, the putting of those components together requires a bit of re-engineering of the car. Nothing outlandish, but at least work and time.
1. Electromotive CFI and fuel injection. (http://www.electromotive-inc.com/) This is a TEC2 unit, which was state of the art when purchased in 1998, but for which electromotive now sells far more advanced units. Nonetheless, it includes the coils and allows for laptop control of the fuel injection maps. It interprets inputs from the following sensors: crank position sensor, throttle position sensor, coolant temp sensor, air intake temperature sensor, manifold air pressure sensor, and O2 sensor. Outputs include: tachometer, high pressure fuel pump control, check engine light, and of course the fuel injectors. Electromotive is the source of all the sensors, injectors, etc.
2. Throttle bodies and fuel rail from TWM Induction (now a subsidiary of Borla Induction, http://www.borla.com/products/induction/). These are Weber DCOE style throttle bodies and are engineered to accept a variety of fuel injectors and allows easy mounting of the critical throttle position sensor. The entire setup bolts to the standard Dellorto intake manifold and will accept the standard air-box and filter arrangement.
3. Vacuum regulated fuel pressure regulator.
4. Rebuilt tachometer from West Valley Auto Electronics to work with the output from the TEC2.
5. Swirl pot / surge fuel tank mounted in the trunk, fed by the standard low pressure fuel pump to allow a source of fuel for the high pressure pump without accidentally sucking air due to slosh as is apt to happen in the main tank.
6. New 5/16 steel fuel lines, both delivery and return. These follow the path of the original line and the vacuum return line, but for convenience, the direction of flow is reversed.
7. Wiring harness. This was an undertaking as the harness was built from scratch, although I’m told with newer Electromotive systems, readymade wiring harnesses are available.
8. Mounting of the toothed wheel and crank position sensor. This required a bit of engineering. The toothed wheel was installed by the engine builder. The sensor mount I made myself using sheet steel. It’s rigid enough, but not nearly as nice as Steve’s, whose is a work of art.
A word about the manifold air pressure sensor vs. a mass airflow sensor. The electromotive unit will accept input from either. All modern vehicles use mass air flow. It’s probably better and more accurate, but requires tight control of air flow. In other words, absolutely no leaks. Manifold air pressure sensing requires the same, but by design is a more forgiving and thus we chose it for our application. In a word, it’s much easier to install.
As of about 4 or 5 weeks ago, we have a running car. By entering basic parameters into the Electromotive computer, injection and timing maps are created which will allow the engine to start. Very rough tuning can then be done using the rich / lean meter seen on a connected laptop computer. But to tune it properly beyond that, requires a dyno and experience. The plan is to bring the car to a tuning shop and tune it on the dyno. My understanding is that this is the only way to do it.
The attached pictures I think tell the story well.
Hope this helps anyone thinking of taking on such a project.
Video of engine running:
Crank position sensor and toothed wheel:
Slosh tank and fuel lines: