Engine - Hesitation or Flare
83renault110E030
APRIL 1983
L42-M42
ENGINE - THROTTLE BODY Attention: Workshop, Parts Department
FUEL INJECTION SYSTEM
INFORMATION
On some A/C equipped L42-M42 models built prior to VIN 1AMXXXXXXXX139766, the engine may hesitate when the A/C compressor engages at idle speeds, or flare when the compressor disengages at idle.
The problem can be corrected by installing an engine idle speed modulating circuit in the throttle body fuel injection system. The circuit regulates engine speed during closed throttle operation and is included on A/C equipped L42-M42 models built after the above VIN. The circuit components are available in a parts kit for use on prior models and vehicles with dealer installed A/C.
FIGURE 1 - ENGINE SPEED MODULATING CIRCUIT COMPONENTS:
Circuit components consist of an idle air bypass solenoid, time delay relay, solenoid air filter, and the necessary vacuum/electrical harnesses (Fig. 1). In operation, when the A/C compressor is about to engage, current flow to the compressor clutch is interrupted for 0.3 to 0.8 seconds by the time delay relay. At the same time, the idle air bypass solenoid opens allowing additional airflow into the intake manifold through the vapor canister purge line.
The additional airflow creates a lean condition causing the oxygen sensor to signal the ECU that mixture enrichment is needed. The ECU responds by having the idle speed control motor open the throttle an additional amount increasing idle speed. Once idle speed is increased, the delay relay resumes current flow to the compressor clutch allowing compressor engagement.
When the compressor is about to disengage, the circuit works in reverse allowing a return to normal idle speed just prior to compressor shut-off.
NOTE: The new circuit applies only to models with A/C and throttle body fuel injection.
Filing Instructions
File this I.S. Note at the back of the plastic binder supplied with your M.R. 240 manual.
FIGURE 2 - CIRCUIT HARNESS ROUTING SOLENOID AND FILTER INSTALLATION, AND VACUUM LINE CONNECTION:
PROCEDURE
1. Disconnect the battery negative cable.
2. Remove the black plastic shield that covers the starter relay, diagnostic connector and other vacuum/electrical components on the passenger side inner fender panel.
3. Remove the air cleaner.
4. Mount the idle air bypass solenoid on the engine compartment dash panel as follows: Remove the bolt that attaches the engine wire harness retaining clip to the dash panel. Insert this bolt through the solenoid mounting bracket and retaining clip and attach the solenoid and clip to the dash panel (Fig. 2).
NOTE: The engine wire harness retaining clip is located next to the coil module on the dash panel.
5. Disconnect the evaporative canister purge line from the T-fitting in the PCV outlet hose and insert the Y-fitting into the disconnected end of the purge line (Fig. 2).
6. Disconnect the orange feed wire from the A/C compressor black lead wire.
7. Position the modulating circuit wire harness in the engine compartment. Position the time delay relay near the starter solenoid and route the circuit harness along the engine compartment harness. Be sure to keep the harness clear of the exhaust manifold and EGR valve.
FIGURE 1 - ENGINE SPEED MODULATING CIRCUIT COMPONENTS:
8. Connect the orange wires of the modulating circuit harness to the A/C compressor black lead wire and orange feed wire and connect the air bypass solenoid wires to the harness connector (Fig. 1).
FIGURE 3 - TIME DELAY RELAY INSTALLATION:
9. Connect the circuit wire harness connector to the time delay relay (Fig. 3).
10. Remove the starter relay from the inner fender panel but do not disconnect any of the relay wires.
11. Position the time delay relay mounting tab against the bottom edge of the diagnostic connector mounting bracket (Fig. 3). Mark the center of the delay relay mounting tab hole on the inner fender panel and punch a hole at this point large enough to accept a #8 sheet metal screw.
12. Attach the time delay relay to the inner fender panel using the #8 sheet metal screw supplied with the kit and reattach the starter relay to the inner fender panel.
13. Attach the modulating harness ground wire to the same screw that attaches the engine harness ground wire to the passenger side spring tower.
14. Install the plastic shield over the delay relay, starter relay, and other vacuum/electrical components on the passenger side inner fender panel.
FIGURE 2 - CIRCUIT HARNESS ROUTING SOLENOID AND FILTER INSTALLATION, AND VACUUM LINE CONNECTION:
15. Connect the air filter to the bypass solenoid and secure the filter to the power steering hose with tie straps (Fig. 2).
FIGURE 4 - VACUUM LINE SCHEMATIC:
16. Check modulating circuit vacuum connections (Fig. 4).
17. Secure the modulating circuit wire harness with as many plastic tie straps as necessary.
18. Connect the battery negative cable and reinstall the air cleaner.
19. Start the engine and operate the A/C system. Allow the compressor to cycle on and off several times before proceeding to Step 20.
20. Connect a tachometer to the engine and check modulating circuit operation. Engine idle speed should decrease by no more than 100 to 150 rpm when the A/C clutch engages, and momentarily increase by no more than 300 to 350 rpm when the A/C clutch disengages.
NOTE: Do not attempt to use the tachometer in the vehicle to check circuit operation. Use an external unit with expanded rpm scale for accuracy.
PARTS
Description Quantity Part Number
KIT, Engine Idle Speed 1 89 33 001 439
Modulating Circuit (With Throttle Body Fuel Injection And A/C Only)
S.R.T. INFORMATION
Operation
Operation Description T.I.C. Number S.R.T.
CO. ENGINE IDLE SPEED MODULATING 8-864 8999 0.6
CIRCUIT KIT - INSTALL