Chevy Impala Tuned Port Injection - A Big Improvement

With the manifold in place, liquid Teflon was applied to all the intake manifold bolts and they were torqued to 18 ft-lb in the correct sequence.

With the plenum and throttle body in place, a Lokar aluminum throttle bracket was installed. The inlet fuel line connection was made at the rear of the fuel rail and the return line connects to the regulator. Also note that the MAP sensor is mounted in this area so that the distributor cap cover will cover it. The MAP sensor must be on a separate vacuum line.

After the manifold was tightened down we installed an electronic distributor and a set of Taylor Spiro Pro 8mm spark plug wires. At this point the intake runners were installed. The passenger-side tube has a taper on the top front and the driver side tube is level across the top. We also installed an S&P 360/10-degree O-ring swivel water neck with a 195-degree thermostat. This water neck will fit under the throttle body and allow you to position the upper radiator hose where needed.

Since this car will be driven in cold weather, we hooked the bypass hose from the intake to the idle speed motor housing located under the throttle body. Then the heater hose was attached to the outlet on the passenger side of the idle speed motor housing. This will help to prevent the throttle body from icing up in severe cold weather driving. With the coolant system completed, the Lokar throttle and detent cables were installed. It's important to make sure that you check for clearance of the throttle arm and binding of any cables. When all connections are made, you should check that the throttle arm will return freely to idle position. This practice should also be used when any interior work is performed.

A steel O2 bung from S&P is welded into the exhaust system. (Only one is needed with a TPI system). If you have full-length headers, you will need to use heated O2 sensors. With a short headers or if you weld the bung close to the stock manifold you can use a one-wire O2.

This car received an S&P PN 1227727 computer, which is heat and weather resistant. An updated version of this computer is the PN 16198260. If you would like to install the computer inside the vehicle you can use PN 1227730, 16196344, 16198262 or the updated 88899196. The, a custom programmed chip from S&P was installed to match the engine, cam and transmission setup which is under the computer's lid.

A Lokar throttle, emergency brake and dimmer switch pedal covers for a '69 Camaro were used in this Impala. Only one hole had to be drilled to mount the gas pedal and then the factory pedal ball studs were removed from the floorboard. The brake pedal used a Lokar '55 Chevy power brake cover with slight modification.

An S&P polished air foil was added to improve the airflow through the throttle body, which is proven to provide up to 15 more horsepower on a mild 350 engine.

After installing the S&P TPI design chrome valve covers on, the PCV valve stainless steel hardline from the S&P aluminum PCV valve to the vacuum port on the intake was routed between the driver side runners. If you have power brakes, the booster vacuum line should be connected to the vacuum port on the driver side rear of the plenum and any other vacuum can be connected to this line.

The throttle position sensor was adjusted from .54 VDC to .60VDC closed, and 4.5 to 5.0 VDC at wide open throttle. Higher horsepower engines can have the TPS set up to 8.4 VDC. S&P provides a harness that will allow you to use a digital voltmeter to do the job. (If you have a scanner, use VIN 1G2FS2389NL200001 (92 IROC/TA), and by turning the key to the on position you can set the TPS before starting.)

Installing an S&P liquid-filled fuel pressure gauge is the best way to monitor your fuel pressure at startup and throughout the life of the system. The liquid in the gauge absorbs the shock of the needle, which provides it a longer life. The gauge should read 38 to 40 pounds at idle and 45 to 48 pounds at open throttle. A liquid filled gauge will usually read about 2 pounds less.

A. S&P Liquid filled fuel pressure gauge (85 to 89 uses a long stem 90 to 92 uses a short stem) B. TPI O-ring to AN6 fuel line adaptors (85 to 88 Vette and 85 to 92 Camaro uses a 16mm and 14mm. 89 to 91 Vette uses two 16mm to AN6. The 16mm adaptors are also used for the GM/AC DELCO GF481 fuel filter. 16mm o-ring fittings will also fit the pressure side of the GM/Saginaw power steering pumps.) C. Adjustable fuel pressure regulator.

Another good tool to troubleshoot problems is a noid light, which is used to show that the injectors are pulsing. The Snap-On Blue Point (PN FID8339). A 12-volt test light can also be used by inserting a paper clip into one side of the injector plug and the test light into the other.

The EST bypass disconnect link on the brown wire located by the distributor must be disconnected while setting the timing. Start by setting the base timing at 6 to 8 degrees. Then turn the engine off and reconnect the ESP bypass. The timing should now be 16 to 22 degrees at idle with a slight variation.

Once all throttle connections are completed we checked to be sure that the throttle would work freely before driving the vehicle. At this time it is also good to turn the key on and let the fuel pump pressurize the system. A check of the entire fuel system for any leaks was done before anyone got in for a lap around the block. But once that was complete and A-okay, our big car cruiser was ready to go. And go she did! And a whole lot smoother and more powerful than that old carb-fed mini-Mouse. What a fun (and easily accomplished) reincarnation this big car turned out to be.

The vehicle speed sensor would not clear the cross member so an 8-inch cable was used to connect the vehicle speed sensor to the transmission.

A. 4000-plus manual vehicle speed sensor needed when using a manual speedometer. B. S&P jumper harness for setting throttle position sensor.

TPI Speed Density Computers 1. 1227730, 16198262, 88899196, or 16196344 2. 1227727, 16198260 Waterproof - Heat Resistant Computer 3. S&P Custom Chip On custom chips please specify cubic inches, cam specs, injector #'s, type of transmission, rear gears, tire diameter, and type of vehicle.