Bolt-on options for FAST-ly improving fuel control
Story Mark Ehlen Images Mark Ehlen, MCR staff and Comp Performance Group - December 26, 2013 10:00 AM
A typical street driver, John’s Barracuda is powered by a stock 340 four-barrel AFB with an automatic.
There are a number of EZ-EFI kits available. Some have various options for your fuel system upgrade. In this case, MCR will be installing the base kit and handling the fuel needs separately.
MCR elected to replace the fuel tank with one modified for an in-tank pump.
Rock Valley Auto Parts sells classic replacement fuel tanks already set up with a properly baffled internal pump and the necessary pick-up and return line fittings.
A 1/2-inch line is used for the pick up while a 3/8-inch is sufficient for the return. The connector supplies power to the pump and the sending unit is included and can be wired directly to your original gauge.
Your factory diaphragm pump will no longer be needed so you’ll need to remove it and install a block off plate.
Don’t be tempted to use your original fuel line and just add new one for the return. Steel lines can rust out and, at 43 psi, a leak won’t be just a drip but rather a potentially very dangerous high-pressure spray.
The FAST 4150 throttle body will work with any 4150-type intake and also works with the original carb-style throttle linkage. Just bolt it in place.
The FAST ECU is weatherproof, so it can be mounted under the hood, but the ECU does need to be mounted at least two feet away from any noisy electrical components such as coils, ignition boxes, etc.
The ECU location takes advantage of an existing hole in the firewall. It’s recommended that you pre-route all the wiring to the throttle body and all the sensors to check for proper length.
Just plug in the labeled connectors to the four injectors, the throttle position and air temp sensors on the right side, the idle control motor in the back and the MAP sensor on the right side above the throttle linkage.
FAST supplies a bung that you’ll need to weld into your exhaust just after the collector to mount the wide band oxygen sensor. Be sure that there are no exhaust leaks as any outside air will mislead the system.
The FAST ECU will control the fuel pump and an electric fan but of course you’ll need to route those signals through a relay. The system will also sense when the A/C has been turned on and bump the idle speed and turn on the fan (if used).
The throttle body works with the original throttle cable and kick down, there is a fuel pressure regulator to maintain 43 psi, and the factory dual-point has been swapped for an MSD Pro-Billet Ready-to-Run distributor.
To the sharp eye, the extra wiring and the fuel pressure regulator are a quick giveaway but otherwise, at first glance with the air cleaner on, one wouldn’t know this was an EFI engine.
The FAST hand-held display can be used to monitor air/fuel ratios as well as the other sensor inputs and even customize your idle speed and air/fuel ratios.
Even though MCR used its chassis dyno to “drive” John’s Barracuda to give the ECU some miles to learn this 340, all that’s necessary is to simply drive the car.
Electronic fuel injection has been on all of our daily drivers for decades now.
Even the most diehard old school traditional hot rodder out there has to admit that nothing beats EFI for maintenance-free, casual, get around town driving. Of course, there’s always some out there that enjoy tuning and tweaking a carb and some of you take pride in knowing how to deal with a flooded engine, vapor lock, or a stuck choke. The rest of us just want to be able to simply turn the key and go.
Safe to say that most, if not all of our readers, have heard about the various stand-alone EFI systems that are now available for pretty much any application. The level of sophistication in these systems is really quite remarkable. They allow you to very precisely control the fuel and spark at any rpm and under any load condition and power level. They actually make it possible to put many of the exotic engines we’re seeing now days in a street ride.
But what if you don’t want to learn how to set up VE tables, or understand how to program a temp versus fuel enrichment table (choke), or set up a percent of fuel enrichment versus throttle position opening rate (accelerator pump). What if you are a complete computer illiterate but you’d still like to have the benefits and fuel efficiency of EFI?
Fuel Air Spark Technology (FAST) has an answer. Their EZ-EFI system is a complete bolt-on package that can be installed and set up without any programming or computer experience whatsoever. But even though it truly is a bolt-on system, it does give you a lot of customizable options. Through its hand-held device, you can set your idle speed, adjust your air/fuel ratios at idle, cruise and wide-open throttle, adjust the amount of fuel added with its accelerator pump function, and even set a rev limiter rpm.
More than that, it has a "pre-squirt" feature that injects a little fuel when the key is turned on and you can add more if you like by pumping the pedal. If you go too far and flood it, wide-open throttle activates the "flood clear" mode shutting off all fuel. You can even monitor your air/fuel ratios during real-time driving. This system really behaves like a regular carburetor but with all the precision of real time closed-loop EFI. In short, you’ll have the ability to tune this set up to your specific engine pretty much just like you would your carb.
An important factor for the proper operation of the FAST ECU is that it receives a clean rpm signal from the coil. The negative side of the coil is electrically one of the noisiest points on an engine so FAST supplies an rpm module that, in most cases, will clean up the rpm signal to the ECU. A better solution is the use of a capacitive discharge ignition that supplies a clean processed tach signal. MSD’s Pro-Billet Ready-to-Run distributor is not only much more stable than the stock dual point, it is also a self-contained ignition system so an external ignition box is not necessary.
The EZ-EFI employs an active learning feature, which allows the system to effectively "learn" your engine and tune itself. It does this by monitoring engine speed, load and air/fuel ratios and then comparing these against pre-programmed base fuel tables that are stored in its ECU. These tables are adjusted for your engine based on your answers to various set up questions such as engine size, number of cylinders, and fuel pressure, etc.
The FAST engineers have used their vast experience with EFI to provide "safe" fuel tables for your initial start up. As you begin driving, the system monitors the real-time air/fuel ratios and makes instantaneous adjustments to the amount of fuel the tables dictate so as to maintain proper air/fuel ratios. Over time, the programming uses the oxygen sensor feedback to adjust the underlying base fuel tables so the closed-loop feedback part of the system needs to make fewer and less intense adjustments. All this happens behind the scenes without any input from you at all. You can speed up the process by purposely taking your engine through a variety of different conditions. It should be noted that you shouldn’t expect big power gains switching to EFI but nevertheless this one picked up an additional 20hp at the rear wheels. That, along with improved drivability will make for a better driving experience.
FAST’s EZ-EFI will support 550hp with a single throttle body and over 1,000hp with a dual-quad set-up. For the most part, the system really is plug-and-play but chances are you will need to upgrade your entire fuel system with any classic muscle car, since EFI requires a high-pressure system with a second return line. An ignition system upgrade may also be necessary. To see how EZ this EFI system from FAST really is, we’re going to show you how it went with a ’68 Barracuda with a 340 four-barrel that belongs to John Balow, owner of Muscle Car Restorations in Chippewa Falls, Wisconsin.