VOLKSWAGEN CORRADO 1993 Repair Manual

WAVEFORMS - INJECTOR PATTERN TUTORIAL
Article Text (p. 22)
1993 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Wednesday, March 22, 2000 09:26PM
The known-good waveform in Fig. 13 is from a Chrysler 3.0L V6
PFI VIN [3]. It is a perfect example of the peak and hold theory. The
waveform shows a 1-amp per division current flow, ramping to 4 amps
and then decreasing to 1-amp to hold the injector open.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
Article Text (p. 23)
1993 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Wednesday, March 22, 2000 09:26PM
The next waveform is from the same type of engine, except
that it shows a faulty injector. See Fig. 16. Notice that the current
went to almost 5 amps and stayed at 1 amp during the hold pattern.
Excessive amounts of current flow from bad injectors are a common
source of intermittent computer shutdown. Using a current waveform
pattern is the most accurate method of pinpointing this problem.Fig. 15: Single Injector w/Normal Current Flow - Current PatternFig. 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.

WAVEFORMS - INJECTOR PATTERN TUTORIAL
Article Text (p. 24)
1993 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Wednesday, March 22, 2000 09:26PMFig. 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. 18 illustrates the 64 volt inductive kick on this
engine, indicating no clamping is occurring. The second pattern,
Fig. 19, was taken during hot idle, closed loop, and no load.

WAVEFORMS - INJECTOR PATTERN TUTORIAL
Article Text (p. 25)
1993 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Wednesday, March 22, 2000 09:26PMFig. 18: Injector Bank - Known Good - Voltage Pattern

WAVEFORMS - INJECTOR PATTERN TUTORIAL
Article Text (p. 26)
1993 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Wednesday, March 22, 2000 09:26PMFig. 19: Injector Bank - Known Good - Voltage Pattern
EXAMPLE #2 - VOLTAGE CONTROLLED DRIVER
The known-good waveform pattern in Fig. 20 is from a GM 3.8L
V6 PFI VIN [3]. It was taken during hot idle, closed loop and no load.

WAVEFORMS - INJECTOR PATTERN TUTORIAL
Article Text (p. 27)
1993 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Wednesday, March 22, 2000 09:26PMFig. 20: Injector Bank - Known Good - Voltage Pattern
EXAMPLE #3 - VOLTAGE CONTROLLED DRIVER
This known-good waveform pattern, Fig. 21, is from a GM 5.0L
V8 TPI VIN [F]. It was taken during hot idle, closed loop and no load.

WAVEFORMS - INJECTOR PATTERN TUTORIAL
Article Text (p. 28)
1993 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Wednesday, March 22, 2000 09:26PMFig. 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.

WAVEFORMS - INJECTOR PATTERN TUTORIAL
Article Text (p. 29)
1993 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Wednesday, March 22, 2000 09:26PMFig. 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. 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. 24, was
taken during hot idle, closed loop, and no load.

WAVEFORMS - INJECTOR PATTERN TUTORIAL
Article Text (p. 30)
1993 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Wednesday, March 22, 2000 09:26PMFig. 23: Injector Bank - Known Good - Voltage Pattern

WAVEFORMS - INJECTOR PATTERN TUTORIAL
Article Text (p. 31)
1993 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Wednesday, March 22, 2000 09:26PMFig. 24: Injector Bank - Known Good - Voltage Pattern
EXAMPLE #6 - CURRENT CONTROLLED DRIVER
This known-good pattern from a Ford 3.0L V6 PFI VIN [U]
illustrates that a zener diode inside the computer is used to clamp
the injector's inductive kick to 35-volts on this system. See Fig. 25.