Fuel Injector Solenoid Coil Test. Cadillac Concours 1997

For 1990-2009 cars

Refer to

#### Fuel Injectors

Engine Controls Components
IAT/ ECT/ TP/ MAP and BBV Sensors
Fuel Pump and Relay
OBD II Symbol Description Notice
ESD Notice
for an electrical diagram of this circuit.

The Injector Flow/Voltage Drop Check compares the fuel pressure drop when each injector is pulsed for a set amount of time. Since each injector is pulsed the same, the fuel pressure drop for each injector should be approximately the same. Suspect fuel injectors can be identified by either too high or too low fuel pressure drop. This check also determines if the voltage drop of the injector is within specification. Injector voltage drop out of specification can cause driveability conditions that are intermittent or that do not show up during an injector flow check.

#### Tools Required

J 34730-1A Fuel Pressure Gauge, J 39200 Voltmeter, J 39021 Fuel Injector Tester.

### Test Description

Number(s) below refer to the step number(s) on the Diagnostic Table.

1. Commanding the fuel pump on for 5 seconds will energize the fuel pump to build fuel pressure. Then selecting individual injectors will allow you to see the fuel pressure drop associated with each injector. If all eight injectors drop some pressure then the circuit is not open. Any injector that drops no pressure has an open in the circuit or a faulty injector.

2. Checking if a fuse was open causing either injectors 2, 3, 5, 8, or 1, 4, 6 and 7 not to operate.

3. Checking if ignition positive voltage feed is open from the fuse to the connector.

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | Go to Step 2 | Go to A Powertrain On Board Diagnostic (OBD) System Check
2 | Has the Fuel System Check been performed? | -- | Go to Step 3 | Go to Fuel System Diagnosis (Fuel System Check)

3

1. Place key in lock position.
2. Install fuel pressure gage, J 34730-1A, fuel injector tester, J 39021 and the Scan Tool.
3. Select Special Functions on the scan tool.
4. Select Fuel Systems on the scan tool.
5. Then select Injector Flow
6. Monitor the fuel pressure, select Fuel Injector Flow Test on the fuel injector tester and test fuel injector #1.
7. Monitor the fuel pressure after injector test and subtract from the fuel pressure noted prior to the injector test.
8. Repeat steps 2 through 4 for injectors 2 through 8.

Does fuel pressure drop when each injector is tested?

--

Go to Step 7

Go to Step 4

4 | Do two or more fuel injectors have no pressure drop? | -- | Go to Step 5 | Go to Step 11

5

1. Place key in lock position.
2. Remove and inspect I/P fuse block injector 1 and injector 2 fuse.

Are both fuses OK?

--

Go to Step 6

Go to Step 14

6

1. Disconnect the fuel rail connector and key On.
2. Set the DVM to the tenths scale (0.0).
3. Measure voltage to ground at the two ignition positive feed pins circuits (engine harness side).

Do both pins measure greater than the specified value?

10V

Go to Step 15

Go to Step 17

7

1. Select Coil Test on fuel injector tester and test all injectors.
2. Set the amperage supply selector switch on the fuel injector tester to the 0.5 position.

Did voltage reading for any injector exceed the specified value?

9.5V

Go to Step 18

Go to Step 8

8 | Inspect the highest reading and subtract the specified value. Was the voltage for any injector less than this value (more than .55 volts less than the highest)? | 0.55V | Go to Step 19 | Go to Step 9
9 | Have any injectors been replaced up to this point? | -- | Go to Step 20 | Go to Step 10
10 | Were the fuel pressure drops recorded in Step 3 for all injectors within the specified value? | 2 PSI | Go to Fuel Injector Balance Test | Go to Step 21

11

1. Select Coil Test on the fuel injector tester and test injector which had no fuel pressure drop.
2. Set the amperage supply selector switch on the fuel injector tester to the 0.5 position.

Does coil test voltage measure between the specified value?

5.74-7.0 V

Go to Step 12

Go to Step 13

12

1. Reconnect the fuel rail connector, disconnect PCM connector C2, and Key On.
2. Measure voltage to ground on PCM pin for suspect injector.

Does voltage measure the same or greater than the specified value?

10V

Go to Step 22

Go to Step 23

13 | Check fuel rail harness for opens or shorts in suspect injector circuits. Open or short found? | -- | Go to Step 24 | Go to Step 25
14 | Check CKT(s) ignition positive feed circuits for shorts to ground. Was a short found? | -- | Go to Step 26 | Go to Step 27
15 | Measure resistance at the fuel rail connector (fuel rail side) across suspect injector circuits. Do any measure less than the first specified value or greater than the second specified value? | 8 to 25 ohms | Go to Step 16 | Go to Step 12
16 | Connect fuel injector tester to suspect injector(s) and select Coil Test. Does voltage reading from coil test measure between the specified values? | 5.74-7V | Go to Step 28 | Go to Step 29
17 | Repair open ignition positive feed circuits between the fuse and the fuel rail connector. Was a repair made? | -- | Go to A Powertrain On Board Diagnostic (OBD) System Check | --
18 | Replace injector(s) whose voltage reading exceeded the specified valve. Was a repair made? | -- | Go to A Powertrain On Board Diagnostic (OBD) System Check | --
19 | Replace injector(s) whose voltage reading was more than 0.55 volts less than the highest voltage reading Was a repair made? | 0.55V | Go to A Powertrain On Board Diagnostic (OBD) System Check | --
20 | Duplicate conditions under which customer complaint occurred and verify proper operation. Is the system operating OK? | -- | System OK | --
21 | Replace injector(s) whose pressure drop was not within the specified value of the others. Was a repair made? | -- | Go to A Powertrain On Board Diagnostic (OBD) System Check | --
22 | Check PCM terminal contact and if OK, replace the PCM. Refer to PCM Replacement/Programming . Was a repair made? | -- | Go to A Powertrain On Board Diagnostic (OBD) System Check | --
23 | Repair open between the fuel rail connector and the PCM in suspect circuit. Was a repair made? | -- | Go to A Powertrain On Board Diagnostic (OBD) System Check | --
24 | Repair circuit. Was a repair made? | -- | Go to A Powertrain On Board Diagnostic (OBD) System Check | --
25 | Replace injector. Refer to Fuel Injector Replacement . Was a repair made? | -- | Go to A Powertrain On Board Diagnostic (OBD) System Check | --
26 | Repair short and replace blown fuse. Was a repair made? | -- | Go to A Powertrain On Board Diagnostic (OBD) System Check | --
27 | Replace blown fuse. Was a repair made? | -- | Go to A Powertrain On Board Diagnostic (OBD) System Check | --
28 | Repair fuel rail harness for suspect injector. Was a repair made? | -- | Go to A Powertrain On Board Diagnostic (OBD) System Check | --
29 | Replace suspect injector. Refer to Fuel Injector Replacement . Was a repair made? | -- | Go to A Powertrain On Board Diagnostic (OBD) System Check | --