Ford Festiva. Instruction — part 74

Fig. 16: Single Injector w/Excessive Current Flow - Current Pattern

EXAMPLE #8 - CURRENT CONTROLLED DRIVER

This known-good CPI system waveform from a GM 4.3L V6 CPI VIN [W] peaks at 4 amps and holds at 1-amp. See

Fig. 17

for waveform.

Fig. 17: Single Injector w/Normal Current Flow - Current Pattern

VOLTAGE WAVEFORM SAMPLES

EXAMPLE #1 - VOLTAGE CONTROLLED DRIVER

These two known-good waveform patterns are from a Ford 4.6L V8 VIN [W]. Fig.

Fig. 18

illustrates the 64 volt inductive kick on this engine,

indicating no clamping is occurring. The second pattern, Fig.

Fig. 19

, was taken during hot idle, closed loop, and no load.

NOTE:

This is GENERAL information. This article is not intended to be specific to any unique situation or
individual vehicle configuration. For model-specific information see appropriate articles where
available.

Fig. 18: Injector Bank - Known Good - Voltage Pattern

Fig. 19: Injector Bank - Known Good - Voltage Pattern

EXAMPLE #2 - VOLTAGE CONTROLLED DRIVER

The known-good waveform pattern in Fig.

Fig. 20

is from a GM 3.8L V6 PFI VIN [3]. It was taken during hot idle, closed loop and no load.

Fig. 20: Injector Bank - Known Good - Voltage Pattern

EXAMPLE #3 - VOLTAGE CONTROLLED DRIVER

This known-good waveform pattern, Fig.

Fig. 21

, is from a GM 5.0L V8 TPI VIN [F]. It was taken during hot idle, closed loop and no load.

Fig. 21: Injector Bank - Known Good - Voltage Pattern

EXAMPLE #4 - CURRENT CONTROLLED DRIVER

From 1984 to 1987, Chrysler used this type injector drive on their TBI-equipped engines. See

Fig. 22

for a known-good pattern. Instead of the

ground side controlling the injector, Chrysler permanently grounds out the injector and switches the power feed side. Most systems do not
work this way.

These injectors peak at 6 amps of current flow and hold at 1 amp.

Fig. 22: Single Injector - Known Good - Voltage Pattern

EXAMPLE #5 - CURRENT CONTROLLED DRIVER

These two known-good waveform patterns are from a Chrysler 3.0L V6 VIN [3]. The first waveform, Fig.

Fig. 23

, is a dual trace pattern that

illustrates how Chrysler uses the rising edge of the engine speed signal to trigger the injectors. The second waveform, Fig.

Fig. 24

, was taken

during hot idle, closed loop, and no load.

Fig. 23: Injector Bank - Known Good - Voltage Pattern