Fuel Injector - Rough Idle/Long Crank Time
91chrysler02
SUBJECT: Approved Diagnostic Procedure For Long Crank Times - 3.0L MMC Equipped
NO.: 18-01-91
GROUP: DRIVEABILITY
DATE: Feb. 11, 1991
MODELS:
1989-91 (AA) SPIRIT/ACCLAIM
1989-91 (C/AC) DYNASTY/NEW YORKER/LANDAU
1990-91 (AG) DAYTONA
1990-91 (AJ) LEBARON COUPE/LEBARON CONVERTIBLE
1990-91 (AQ) CHRYSLER'S TC (MASERATI COUPE)
1987-91 (S/AS) CARAVAN/GRAND CARAVAN/CARAVAN C/V
VOYAGER/GRAND VOYAGER/TOWN & COUNTRY
THIS BULLETIN SUPERSEDES TECHNICAL SERVICE BULLETINS 18-16-88, 18-11-89 (Revision A) AND 18-12-89, WHICH SHOULD BE REMOVED FROM YOUR FILES.
THIS IS THE ONLY APPROVED DIAGNOSTIC PROCEDURE TO VERIFY LEAKING FUEL INJECTORS ON 3.0L MMC ENGINES.
DISCUSSION:
If the customer complains of "Long crank time" or "Long crank time associated with an engine "miss" and/or rough or erratic idle", the following diagnostic procedure must be followed. Use the DRB II tester and the appropriate diagnostic procedure manual to verify that all vehicle engine systems are functioning as designed. If Fault Message "Injector Peak Current" (code 26) or Fault Message "Injector Control Circuit" (code 27) is present, repair the condition per instructions in the diagnostic manual. If all systems are functioning correctly (no fault codes are present), and leaking injectors are suspected, perform the following procedure.
PARTS REQUIRED:
2 Plenum Gaskets PN MD094128
1 EGR Gasket (for 87 & 88) PN MD103625
1 Vacuum Tee (1/4 x 1/4 x 1/4) PN 4306994*
1 Vacuum Connector (1/4 x 1/4) PN 4201275*
*NOTE: THESE COMPONENTS ARE REUSABLE AND CAN BE USED FOR TESTING OF SUBSEQUENT VEHICLES. THE EXACT VACUUM TEE AND VACUUM CONNECTOR MUST BE USED FOR THIS TEST. THE USE OF OTHER SIZE TEES OR CONNECTORS WILL RESULT IN INVALID TEST RESULTS. ALL OTHER EQUIPMENT MUST BE USED AS SPECIFIED.
DIAGNOSTIC PROCEDURE:
1. Start and run engine until it reaches operating temperature. Wait until radiator fan cycles twice, then turn off engine. This procedure must be performed while the engine is at normal operating temperature.
2. Remove shop exhaust hose from tailpipe, if it was connected during engine warmup.
3. Remove air inlet duct to the throttle body. Remove throttle linkage. On 1987 and 1988 vehicles, remove the EGR tube attached to the intake plenum. Remove top of intake plenum.
4. Using compressed air, blow out the intake manifold runners for EXACTLY FIVE (5) SECONDS EACH.
5. Remove coil ignition cable from distributor cap and attach to a good ground.
6. Use the DRB II to actuate fuel pump to pressurize the fuel system (for 1987 and 1988 vehicles use ATM mode 01 "coil spark", and for 1989 through 1991 vehicle use ATM "ignition coil"). Keep ATM activated for one minute (MUST BE EXACTLY ONE MINUTE) then exit ATM.
7. Obtain a 5 foot long section of 1/4" I.D. rubber hose (MUST BE EXACTLY 5 FEET OF 1/4" I.D. HOSE) to be used as an air sample line connected to a hydrocarbon exhaust gas analyzer. Make sure that the exhaust gas analyzer has a clean filter and is calibrated before performing this test.
Figure 1:
8. Install vacuum connector (PN 4201275) in the sample line at the end to be inserted into the intake manifold runner. Install vacuum tee (PN 4306994) at EXACTLY the middle of the sample line so that fresh air will be drawn in (see Figure 1).
9. Wait for EXACTLY FIVE (5) MINUTES after exiting ATM, and then, one by one, insert the sample line approximately 5-6" down into each intake manifold runner (MARK THE HOSE WITH A PIECE OF TAPE SO THAT THE HOSE IS INSERTED EXACTLY THE SAME DISTANCE INTO EACH RUNNER). Record the peak HC (hydrocarbon) reading for each intake runner, being sure to let the analyzer reset to zero (0) before taking the next reading.
Figure 2:
NOTE: THE INTAKE MANIFOLD IS A CROSSOVER DESIGN. THEREFORE, TO TAKE READINGS FOR CYLINDERS 2, 4, AND 6 (WHICH ARE NEAREST THE FRONT OF THE VEHICLE), THE REAR MANIFOLD RUNNERS MUST BE CHECKED (FIGURE 2).
10. After taking the readings from each intake runner, replace that cylinders injector only if HC readings are 100 ppm or greater.
NOTE: INJECTORS SHOULD NOT BE REPLACED BASED ON CAP COLOR. COLOR IS NOT AN INDICATION OF A FAULTY INJECTOR AND MIXED COLORS IS NOT DETRIMENTAL TO THE OPERATION OF THE ENGINE.
11. Reinstall intake manifold plenum and torque bolts to 13 N-m (115 in.lbs.). On 1987 and 1988 vehicles, reinstall EGR tube to intake plenum and torque to 22 N-m (200 in.lbs.).
12. Reinstall the throttle cables and air inlet duct.
13. Reinstall coil ignition cable to distributor cap.
POLICY: Reimbursable within the provisions of the warranty.
TIME ALLOWANCE:
Labor Operation No. 14-30-20-68 . . . . . . . . . . . . . . . . . . . . 0.3 Hrs.
(Injector Infra-Red Test)
14-30-20-23 . . . . . . . . . . . . . . . . . . . . 0.9 Hrs.
(Replace 1 to 3 Injectors)
14-30-20-24 . . . . . . . . . . . . . . . . . . . . 1.1 Hrs.
(Replace 4 to 6 Injectors)
FAILURE CODE: 43 - Fuel Leaks