Monday, October 05, 2015
Electronic Fuel Injection

June 26, 2007

All of the following is now obsolete as I have switched from the stock EFI system to a Real World Solutions EC2 system.

July 5, 2004

I've removed the IAC valve body and disconnected it from the intake manifold. The top electronics portion of the IAC is retained to keep the EFI computer happy. A bracket was made to allow this peice to be solidly mounted to the engine.


December 7, 2003

During flight testing I had a number of occasions where Bypass-Air Valve would set error codes and the check engine light would come on during descent to land. Jeff Liot reported this same problem and discovered that it was the Bypass-Air Valve. For some reason, it doesn't care for descent conditions. I have elected to remove my air-bypass valve due to this problem. Two other factors that contributed to the decision was the plumbing required for this valve and the fact that there is really no need for it. It is pretty cool for the engine to control it's own idle but it isn't a necessity. Additionally, I was never very confident in the air line between the MAF sensor and the valve. My setup was pretty bogus and I felt the odds of it failing were high.

October 10, 2003

Still trying to find the source of engine roughness after 15-20 minutes of hard running (flight or ground). I have noticed that the EFI ignitor gets quite hot. Also found that I had forgotten to remove the protective coating from the aluminum plate that I mounted the ignitor on. This probably wasn't helping heat transfer! I have added a home-made heat-sink and cooling fan.


September 18, 2003

I've had to make some modifications to the fuel system due to a vapor lock type problem experienced only in-flight. My theory is that, due to the proximaty of the exhaust system to the EFI pump fuel rail, the fuel was getting too hot and vapor locking. I have added fire sleeve to all exposed fuel line and created a box around the pumps, fuel rail, filter, and coil. Cool air is ducted into this box.

I have also added a fuel pressure sendor and gauge. I purchased a Cyberdyne unit from Jeg's Performance (part # 280-A011E061Y). The ideal gauge would have been the Nordskog B2534 unit that includes a low pressure output (to hit a relay to turn on the aux pump) and light. However; it was back-ordered and I was not willing to wait. You can see the sendor in the photo below. It is mounted in the line between the EFI pumps and the first fuel rail. When mounted in-line like this, you must supply ground to the sensor case (as it is not screwed directly into the block which is how it normally get's grounded).


I have also wrapped the exhaust in an attempt to reduce the heat in the cowling. I am aware that this is VERY hard on the exhaust but vapor-locking in the air is very hard on my seat cushion!.


February 2, 2003

The following is fuel system configuration. The only item that I do not like is that the two transfer pumps are run in series. I would much prefer a parrallel arrangement. However; due to having a single pickup in the main tank and space restrictions, I have decided to go with this arrangement for now.


August 1, 2002

I believe the wiring harness is finished (barring some unforseen problem like the engine won't run!!!). My harness is quite small as the ECU is mounted close to the firewall (inside the cabin). The photo below really doesn't give an accurate idea of how much wire is really removed. That ball of wire is all of the wire removed from the automotive harness (and it is a compact ball of wire!!). Many folks ask about the size of this project - it is a BIG project. I'm certainly not an electronics expert so I spent LOTS of time analyzing wiring diagrams and tracing wires. I did this over and over and over again until I was positive that I had the correct wire and only then would I mark it, cut it, or remove it.


The fuel injection system will be the stock system with the exception of the fuel pumps.

November 15, 2000

The fuel rail has been cleaned up and painted.


June 1, 2002

Fuel injection system is in and working. I have some shortening to do to the wiring harness and lots of cleanup. Also, the clear tubing hoses you see are for testing purposes only, I won't be flying with them.


NOTE: After some flight testing the air-bypass valve was removed. The top portion (the relay the plugs into the ECU) was retained to keep the electrical system happy.
Due to space constraints, I had to come up with an inventive way of mounting the air-bypass valve. I ended up using a 3/4" plate of aluminum mounted to the case. I internally machined this plate and incorporated a 3/4" hose output. This output is connected to the intake manifold.



The dual EFI fuel pumps have been mounted (although they don't look very straight in this photo - will have to work on that). The fuel rail (large aluminum tube at bottom) is fed by 3/8" hose (gravity feed) from header tank (input not yet installed). The pumps are from 1992 Subaru Loyales and include internal check valves.


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