X: Injection Pressure Regulator (IPR)
Introduction
Introduction
1994 PCED OBDI-A | SECTION 18A: Diesel Diagnosis — 7.3L DI Engine |
X: Injection Pressure Regulator (IPR) Introduction | X: Pinpoint Tests |
Injection Pressure Regulator — A variable position valve that controls injection control pressure. The PCM uses many input variables to determine the desired injection control pressure.
Battery voltage is supplied to the IPR when the ignition key is in the ON position. Valve position is controlled by switching the output signal circuit to ground inside the PCM. ON/OFF time is modulated from 0 to 60% dependent upon the desired injection control pressure.
An open or shorted to ground control circuit can be detected by an on demand output circuit check performed during the KOEO test.
The PCM (powertrain control module) is capable of detecting, while the engine is running, if desired injection control pressure is equal to measured injection control pressure. If the measured injection control pressure does not reasonably compare to the desired injection control pressure the PCM ignores the measured ICP signal and attempts to control the engine with the desired value. (If the problem was in the sensor circuit this strategy causes little performance deterioration. If the problem is in the control circuit engine performance will probably still be unsatisfactory).
An injection control pressure step test, in which the PCM commands and then measures specific preprogrammed pressures is performed during the KOER test.
The engine will not operate with an IPR output circuit that is not functioning.
After removing connectors always check for damaged pins, corrosion, loose terminals, etc.
| Test Points | Spec. | Actual | Comments |
|---|---|---|---|
| A to Grd | >5 ohms | If 5 ohms or less, the harness is shorted to ground | |
| B to Grd | >5 ohms | A short to ground will command full IPR pressure |
| Test Points | Spec. | Actual | Comments |
|---|---|---|---|
| A to Grd | B+ | Battery voltage from PCM relay, check with key on | |
| B to Grd | 0-.5 v | If greater than .5 volts signal wire is shorted to VREF or battery |
| Test Points | Spec. | Actual | Comments |
|---|---|---|---|
| No. 83 to 71 or 97 | 2.5 to 15 ohms | Resistance through IPR circuit including regulator. Check with regulator connector connected | |
| No. 83 to B | <5 ohms | Resistance from regulator connector to 104 pin connector | |
| A to 71 or 97 | <5 ohms | Resistance from regulator connector to ignition power |
155 = ICP pressure was greater than 3675 psi for 1.5 seconds (possible grounded IPR control circuit). Refer to injection control pressure diagnostics if not electronic concern.
546 = Output circuit check detected during KOEO test; indicates high or low resistance in circuit.
841 = If set during normal engine operation indicates engine is operating in open loop control and ICP pressure is above or below desired pressure. Refer to ICP control system diagnostics. If set during KOER test, indicates ICP system failed step test and could not maintain commanded pressure.
| X: Pinpoint Tests |