| TPS Adjustment for the 5.0 |
 |
 |
This also works well on DOHC 4.6s, and 3.8s. As much as a tenth and a half have been recorded with this adjustment in the ? mile. I can not explain why this seems to have almost no effect on the SOHC 4.6s.
The second and one of the most important sensors on your EFI engine is the Throttle Position Sensor (TPS). The TPS, which is mounted on top or the side of the throttle body, converts the mechanical motion of the throttle butterfly into an electrical signal, which is relayed to the EEC-IV/V computer. This determines how the computer richens the fuel mixture at low to mid speeds, adjusts spark advance, idle speed and lock-up torque converters.
Proper adjustment of the TPS is vital, particularly on modified engines. If you?ve changed or removed the throttle body, the TPS adjustment definitely needs to be checked. If the TPS is even slightly out of adjustment, it?ll give a false reading which can result in an off idle lag or hesitation when the throttle is opened, and wide open throttle performance will also be limited. Not the best thing for us wanting maximum performance.
There?s two ways to set the TPS, one is to go out and spend $150 on Interactive Systems & Techologies? new digital TPS monitor that plugs directly into the stock harness and has an LED display. Or the old way that I will cover here.
You will need the following tools:
- Digital voltmeter (capable of reading less than 1 volt DC.
- (2) Electrical probe alligator clips
- Electrical probe or paper clip
- Screw driver (Philips head) 94-95 Mustangs and Tbirds need an off set type
- Electric drill ??
- Drill bits
Attach the alligator clips to the ends of both voltmeter leads.
Attach the negative lead to a good ground on the vehicle. Insert the electrical probe or paper clip into the sensor where the center wire penetrates the sensor body insulation, this is the output signal. Set the voltmeter to read DC voltage.
With the engine off but the ignition key in the ?on? position ?key-on engine-off? read the TPS voltage. Ideally, it should read at or just under 1.0 volt. You don?t want over 1.0 volt because the computer will go into an off-idle management mode, which will really screw up drivability. The factory setting can be anywhere from .75 - .85. The idea here is to make the computer think the throttle is farther opened than it really is, so the computer advances the timing and richens the fuel mixture quicker. If the voltage reads over 1.0, or below .98, loosen the two hold-down screws and rotate the sensor body in either direction until the optimum (.98 to 1.0) reading is obtained. The sensor mounting holes are not slotted but there?s usually enough play in the holes to allow you to make the needed adjustments. If you can?t get the correct reading, you may need to enlarge the holes very slightly with the drill. After you complete the adjustment, tighten the two screws securely.
Next, while still in the ?key-on engine-off? mode, slowly open the throttle from the idle stop position to full open and watch the reading. It should advance evenly as you open the throttle, updating every .4 seconds. If the voltage appears unstable at any point, or drops, you may have a defective TPS. The wide-open throttle reading should be between 4.3 to 4.8 volts.
Lonnie
| Sponsor Links |
|
|
|
|
|
|
|
