Volkswagen Corrado (1993 year). Manual - part 220

 

  Index      Volkswagen     Volkswagen Corrado - service repair manual 1993 year

 

Search            

 

 

 

 

 

 

 

 

 

Content   ..  218  219  220  221   ..

 

 

Volkswagen Corrado (1993 year). Manual - part 220

 

 

WAVEFORMS - INJECTOR PATTERN TUTORIAL 

         EXAMPLE #3 - VOLTAGE CONTROLLED DRIVER

         Example #3 is of a Ford 5.0L V8 SEFI. Fig. 10 shows a
waveform of an individual injector at idle with the Lab Scope set on
200 milliamps per division. Notice the dimple in the rising edge. This
dimple indicates the actual opening of the injector (set point)
occurred at 400 milliamps and current peaked at 750 milliamps. This is
a good specification for this engine.
         The next waveform pattern in Fig. 11 shows an abnormality
with another injector. With the Lab Scope set on 500 milliamps per
division, you can see that the current waveform indicates a 1200
milliamp draw. This is a faulty injector.
         Abnormally low resistance injectors create excessive current
draw, causing rough idle, and possible computer driver damage.

Fig. 10:  Single Injector w/Normal Current Flow - Current Pattern

WAVEFORMS - INJECTOR PATTERN TUTORIAL 

         EXAMPLE #4 - CURRENT CONTROLLED DRIVER

         Example #4 is of a Ford 4.6L SEFI VIN [W]. See Fig. 12 for
the known-good waveform pattern. This Ford system is different from
the one above in EXAMPLE #3 as it peaks at 900 milliamps and the
actual opening of the injector (set point) is just below 600
milliamps.
         This is offered as a comparison against the Ford pattern
listed above, as they are both Ford SEFI injectors but with different
operating ranges. The point is that you should not make any broad
assumptions for any manufacturer.

Fig. 12:  Single Injector w/Normal Current Flow - Current Pattern

         EXAMPLE #5 - CURRENT CONTROLLED DRIVER

WAVEFORMS - INJECTOR PATTERN TUTORIAL 

Fig. 13:  Injector Bank w/Normal Current Flow - Current Pattern

         EXAMPLE #6 - CURRENT CONTROLLED DRIVER

         This next known-good waveform is from a Ford 5.0L V8 CFI VIN
[F]. See Fig. 14. The pattern, which is set on a 250 milliamps scale,
indicates a 1.25 amp peak draw and a hold at 350 milliamps.

Fig. 14:  Single Injector w/Normal Current Flow - Current Pattern

         EXAMPLE #7 - CURRENT CONTROLLED DRIVER

         The known-good current controlled type waveform in Fig. 15 is
from a GM 2.0L TBI VIN [1]. With the lab scope set at 2 amps per
division, notice that this system peaks at 4 amps and holds at 1 amp.

WAVEFORMS - INJECTOR PATTERN TUTORIAL 

Fig. 15:  Single Injector w/Normal Current Flow - Current Pattern

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.

 

 

 

 

 

 

 

Content   ..  218  219  220  221   ..