Filter
Top Products
69
1. Fuel Injection Type - In the engine parameters screen, Throttle Body Inj. must be selected for the fuel injection type.
2. TBI Switch – If a TBI system with progressive throttle linkage is used, the following two parameters must be set correctly
or significant problems will occur. They also need to be adjusted with a non-progressive TBI system.
With a progressive linkage, the rear throttle plates do not open until the throttle is approximately 1/3 open. If the rear
injectors are turned on before the rear plates start to open, the fuel would puddle on the throttle plates. The rear injectors
need to be shut off until the rear throttle plates are open. The “TBI Switch 2-4” setting is the TPS position that the rear
injectors turn on. To obtain the proper setting for this, turn the key on and with the engine not running open the throttle
until the rear throttle plates just start to open. Note the TPS position. Add 10 to this number and enter it for the “TBI
Switch 2-4” setting.
The “TBI Switch 4-2” is the TPS position that the rear injectors will turn back off when the throttle is closed. This value
should be about 5 less than the “TBI Switch 2-4” setting.
Figure 54
3. Under “Fuel” and “Startup Enrichment”, you will find what is called “Auto Prime 7 Msec Pulse Count”. This feature allows
you to add some fuel to wet the intake manifold before the engine is started. Most engines, when tuned properly, do not
need to add this extra fuel. The key should just need to be turned and the engine should start. If this is not the case, the
accelerator pedal can be pressed down with the key on and the engine not running, and the amount of fuel programmed
into the area will be added. The value entered is the number of 7 millisecond pulses of fuel that will be added.
5.0L Ford Specific Tuning Information
5.0L Ford engines are typically more sensitive to idle tuning than most other engines. The following are some tips on tuning
these engines.
1. When the engine is up to operating temperature and in neutral, make sure that the idle air control motor (IAC) is fully
closed (signified by a position of 10). If the IAC is contributing to the air needed to idle when the engine is warm, it
sometimes causes instability. To adjust this, very slowly open the throttle plates until the IAC is closed and you are at the
desired idle speed. You may have to have the engine idle slightly higher than the desired idle speed to ensure the IAC
does not open when the engine is in neutral.
2. Make sure you use the idle spark control feature.
3. Make sure the fuel map is smooth in the idle area.
4. Make sure the timing map is “flat” in the idle area.
5. These engines typically like to idle at a leaner air/fuel mixture in order to idle smooth. Richer mixtures at idle sometimes
make the engine surge. Try leaning the idle out if the engine surges.
6. The “P” term can be lowered in the Idle Air Control settings. This will slow the movement of the idle air control motor.
Values as low as 3 to 5 are not uncommon. See what works best for your application.