Inlast month's issue, we outlined the installation of an electronic fuel injection (EFI) system onto the vintage Pontiac V-8 residing in Lou Rotella's 1967 Firebird. Its modified Quadrajet carburetor performed suitably at all speeds, but if the car sat for several days, the fuel in the Q-jet's float bowl usually evaporated, which required excessive cranking to get it started. And even with a fully functional electric choke, the 455 was very cold-blooded and required extended warm-up time before hitting the streets, especially in cooler weather.
While those characteristics may be considered the romance of driving a vintage vehicle with a carbureted engine, it certainly leaves much to be desired when compared to modern fuel-injection systems ... so much so in fact that we were asked to find a complete EFI system for the Firebird's 455 that would provide excellent drivability and performance at all speeds and conditions. That's where Fuel Air Spark Technology (FAST) and its EZ-EFI system come in.
Generally considered among the most user-friendly EFI systems available, EZ-EFI No. 30227-KIT retails for $2,200 and includes all of the required fuel system and electrical components for a proper install, as well as a self-contained throttle body fitted with four fuel injectors. Best of all, it requires only minimal operator input for initial startup and "learns" what the engine wants to perform optimally in all conditions and ranges as you drive it. So how does the EZ-EFI system compare to a modified Quadrajet? Follow along as we detail the initial startup process, fine tune the system programming, and hit the chassis dyno for a power measurement.
1. In last month’s issue of HPP we outlined the process of installing an EZ-EFI fuel injec
The Firebird's 455 is mildly modified and uses mostly stock components. Now displacing 462 ci, its 4X heads flow approximately 230 cfm and produce a compression ratio of 9.7:1, and a 232/243 hydraulic flat-tappet camshaft actuates the valves. It inhales through an Edelbrock Performer RPM intake manifold and exhales through a set of Dynomax tubular headers and a transverse-mounted Flowmaster muffler. Though a relatively simple combination, it's always performed respectably, generating plenty of torque for tire smoking fun—while the lack of traction prevents it from twisting the convertible body into a knot.
Because of time and space constraints, we enlisted T&M Automotive in Omaha, Nebraska, for the EZ-EFI install. Detailed in the previous issue, installation was straightforward without any unexpected problems. A feature FAST boasts about is its EZ-EFI systems Engine Control Unit (ECU) setup for initial engine startup and an adaptive learning mode where the ECU continually adjusts as you drive to achieve optimal performance in all conditions for the particular engine. In other words, once you set the basic parameters, you'll only need to adjust a couple of variables to get your Pontiac running its best. So let's get to it.
2a. FAST recommends setting the fuel pressure for its EZ-EFI system at 43 psi for normal o
2b. FAST recommends setting the fuel pressure for its EZ-EFI system at 43 psi for normal o
3. The fuel pressure regulator supplied by FAST uses engine vacuum to momentarily increase
4. The handheld unit that FAST supplies with its EZ-EFI kits serves several functions, and
5. FAST supplies a serial cable that quickly connects to the communication lead.
6. With the handheld unit connected to the ECU, it requires a 12V power source, so we inse
Initial Startup and Tuning
After performing the required steps outlined by the handheld unit's Setup Wizard, we started the 455 for the first time. As expected, it idled rough and stumbled regularly for the first few minutes. Once the coolant temperature reached 140 degrees F, the ECU switched to adaptive *learning mode. It began to improve our 455's idle quality, but we found unless it was completely up to normal operating temperature, it often died when the Turbo 400 was placed into gear. After experiencing the same symptoms a few more times, we began wondering just what we'd gotten ourselves into!
After mustering the courage to drive it on the street, we found the EZ-EFI system very smooth and responsive at constant speeds, but any abrupt movement of the accelerator caused the engine to stumble and/or die. Drivability and performance was clearly improving as miles accumulated. After about 30 miles of driving in all types of conditions, we parked it for the night and called FAST's technical department to explain our concerns and seek guidance on adjusting the Idle Air Control (IAC) valve to improve cold startup as outlined in the instructions.
FAST Technical Consultant Kevin Winstead took our call and assured us that everything we'd seen up to that point was normal and that we should expect to see further improvements the more we drove it. We explained the cold startup symptoms and he suggested that we first verify the IAC count at hot idle using the Live Data feature on the handheld.
With the throttle blades at a fixed angle, the IAC valve contains an internal solenoid that continually opens and closes to provide the engine with a precise amount of bypass air to produce a stable idle. By adjusting the throttle-blade set screw, we could change the closed angle to allow more or less airflow past, which alters how many times the IAC valve cycles. That cycle is referred to as an IAC count. Reducing the IAC count lessens the number of times is IAC opens, which makes it more effective overall, but particularly when the engine is cold.
After another cold-startup sequence the next day, we found the engine operated better on its own, but was far from our expectations of how a fuel-injected engine should idle. Per Winstead's recommendation, we allowed the engine to reach its normal operating temperature and found the IAC count at hot idle was more than 60, and the instructions recommended about 20. We called Winstead to discuss our finding and he instructed us to adjust the throttle blades until the IAC count drops between 10 and 20, and then recalibrate the Throttle Position Sensor (TPS).
7. The unit should come to life displaying the FAST welcome screen.
8. Navigating through the handheld screens is as easy as using the up/down arrows and Ente
9. We select Setup Wizard on the Main Menu screen (left) and Yes when asked to start a new
10. We cycle the key off, and then return to the Run position, listening for a series of a
11. Upon initial engine startup, we find the engine runs roughly, but continually improves
12. When monitoring live data, we pay particular attention to the circles labeled AL and S
Heeding his advice, we performed the appropriate steps. The next morning we twisted the key and were rewarded with immediate and consistent cold startup. The engine immediately went to high idle (1,000-plus rpm) for several seconds and settled into to our selected idle speed of 850 rpm. The idle was so stable that it was unaffected by gear selection and steering-wheel inputs.
Once up to temperature and on the road, the throttle response was simply amazing. Stepping into the accelerator produced immediate response that propelled the Firebird forward forcefully. Now this is what EFI is all about!
The Power Numbers
We spent hours tinkering with a 800-cfm Quadrajet to get it performing flawlessly at every point under normal driving conditions, and that included several pulls on the chassis dyno to be sure it was dialed in for maximum full-throttle performance. Just before the EFI install, we recorded the 455's output so we might establish a baseline to compare the performance effects EFI might have. After strapping it to the roller drum on the Mustang dyno at H.S. Automotive in Omaha, Nebraska, the 455 recorded a best of 282 hp at 4,800 rpm and 336 lb-ft at 4,100 rpm at the rear tires.
We returned to H.S. Automotive a few weeks later for a follow up dyno session after the EZ-EFI install. We must first preface that a TBI system works much like a carburetor. It still uses traditional throttle blades for air entry, but uses fuel injectors instead of boosters to atomize fuel. Where carburetor jet changes take several minutes and tailoring the air/fuel ratio for a particular engine throughout the entire pull can be tedious, an electronic EFI system can generally be adjusted with a few keystrokes or button pushes, and it can immediately compensate for air temperature and conditions, as well as altitude for maximum possible performance in any condition or location.
The main benefit to an EFI system is its ability to atomize fuel in all conditions and improve driveability in all ranges. We were completely satisfied with what we'd seen from the EZ-EFI system so far and simply hoped to achieve similar peak power numbers from the EZ-EFI. We understood anything more might suggest an issue with the functionality of the Quadrajet we replaced, but anything less may be something we'd have to live with since our intent was improved drivability, and it delivered exactly that.
With the Firebird strapped down, the first pull sounded crisp and clean, but when it commenced, we found the 455 now producing 266 rwhp and 304 rwtq—a loss of about 20 hp and 30 lb-ft. A bit disappointed, dyno operator T.J. Mrsny assured us that the FAST system likely requires a few full throttle pulls for the ECU to adjust accordingly. He suggested a few subsequent pulls and just as he predicted, we saw the numbers climb each time. By the fourth pull we were at 284 rwhp and 337 rwtq—nearly identical to what we saw from the Quadrajet. A few more pulls were made adjusting fuel and timing, but nothing topped the numbers generated with FAST's programmed targets.
14. We had an issue at cold startup where the engine idled suitably, but died whenever a t
15. We were told to adjust the hot-idle IAC count until its between 10 and 20 by adjusting
16. A carburetor uses an accelerator pump to deliver an additional shot of fuel to prevent
17a. We used the Mustang brand chassis dyno at H.S. Automotive in Omaha, Nebraska, to dete
17b. During the baseline test the 455 peaked at 282 hp and 336 lb-ft at the rear tires. Th
18. FAST presets the target air/fuel ratio at full throttle to 12.8:1. It’s easily adjusta
19. The default settings were suitable, but we found our particular 455 idled better with
20. The EZ-EFI throttle body is designed to provide one ported vacuum source. We found on
21. With the Quadrajet in place, we had the distributor’s vacuum-advance unit connected to
The addition of an EZ-EFI fuel injection system has transformed the usability of this particular Firebird. Where it was once difficult to start and drive cold, it now starts immediately and can be driven away within seconds of startup (though we do recommend a minute or two of idle time to allow the fluids to circulate and warm up in cold temps). With as sensitive as the throttle response is, we're certain fuel economy will increase, but we simply couldn't resist stabbing the accelerator to feel the immediate responsiveness the EFI system offers. Best of all, we were able to achieve power numbers nearly identical to the carburetor with minimal tuning effort, and we greatly improved the street manners and overall driveability. That's exactly what the owner was after.
Year/Model: 1967 Firebird 400 convertible
Weight With Driver: Approx 3,750 lb
Engine: 1970 code-YH 455
Cubic Inches Before/After: 455/462
Engine Built By: Willard Auto Machine
Air Cleaner: Open element, 14x2-inch diameter
Fuel Injection: . FAST EZ-EFI throttle body, 1,000+ cfm
Intake Manifold: Performer RPM
Pump: FAST electric fuel pump, 240 lph
Casting: 1974 No. 4X-7H
Head Porting: Mild home porting
Peak Airflow Numbers at 28-inches: 230 cfm
Pistons: TRW forged-aluminum No. L2359F
Rings: Sealed Power replacement
Rods: Stock cast with ARP fasteners
Compression Ratio: Approximately 9.7:1
Crankshaft: Original nodular-iron, 4.21-inch stroke
Rotating Assembly Balanced: Yes
Brand: Nunzi's Automotive hydraulic flat tappet
Duration at 0.050: 232/243-deg
Duration Advertised: 301/313-deg
Lift with Specified Rocker Arms: 0.460/0.470-in
Lobe Separation Angle: 113-deg
Intake Centerline: 109-deg
Rocker Arms: Crower cast-alloy roller, 1.6:1 Ratio
Distributor: Pontiac HEI
Coil: Stock ACDelco
Wires: Taylor 8mm
Spark Plugs: ACDelco No. R45S
Total Timing: 36-deg
RPM Total Timing Is Reached: 3,200
Headers: Dynomax four-tube 1.75-inch primary tubes, 2.5-inch collectors
Exhaust Pipes: 2.25-inch
Muffler: Flowmaster crossflow, No. 42582
Converter: Continental, 2,600 stall
Rear Axle: Original 8.2-in GM 10-bolt
Rear Gear Ratio: 3.55:1