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1985-1991 Corvette Fuel Pressure Regulator Diaphragm

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Brand Logo ACDelco
Part #: 601-034
GM Part #: 19187371
Availability: Out of Stock
Fits Years:
  • 1985-1991
  • Description

1985-1991 Fuel Pressure Regulator Diaphragm

Correct Fuel Pressure = More Horsepower! Keep your 1985-1991 Corvette running at optimum performance!

This diaphragm is located under the dome of regulator, is spring loaded and controls fuel pressure to the injectors. We have compiled a group of the most needed emission parts, and now offer them to you at great prices. These controls, switches and sensors keep your car running smooth and clean for peak performance and low emissions.

How To Do a Minimum Air Set to Adjust the Idle on 1985-1991 L98 Corvettes:

1985-1989 Corvettes Normal idle voltage is: 0.54 to 0.56

1990-1991 Corvettes have a non-adjustable TPS. Voltage range is 0.36 - 0.96 0.72 is the normal idle voltage

1. Jumper across pins A and B in the ALDL connector under the dash, and then, turn on the ignition key. DO NOT START THE ENGINE! You will hear the coolant fan come on and the CHECK ENGINE indicator will start flashing. This is normal.

2. Wait at least 30 seconds with the ignition on, then open the hood and unplug the idle air control motor pindle move out of the shutoff bypass air position.  Remove the ALDL jumper wire.  

3. Unplug the single wire connector on the harness wire by the wiper motor.  It has a tan/black stripped wire.  This is the 5-volt distributor bypass wire that diverts the engine to base timing when it is open. 

4. Start the engine and set the base timing to 6 degree Before Top Dead Center.

5. Remove the idle screw plug on the left side of the throttle body assembly.  Using a 15 Torx tip adjust the idle 450 rpms.

6. Reconnect the IAC connector to the throttle body.

7. Check the TPS (throttle position sensor) voltage.  Loosen the 20 Torx screws and set it to .54 to .56 volts.  Using a digital volt ohmmeter across terminal A (black wire) to terminal B (dark blue wire) to set the switch, or use a scanner.  The engine does not have to be running; only have the ignition switch turned on.

8. Remove the battery cable and then reinstall after 10 seconds.  This erases the code 42 that was set due to the disconnect of the 5-volt bypass distributor wire.

9. Start the engine and vary RPMs.  After the engine is warm, hold the engine at 1500 RPMs for 2 minutes.  This cleans the O2 sensor.

10. Shut the engine off, then restart it.  It should now idle correctly.

Also known under these part numbers: (For reference only)

  • 19187371
  • 214-2156
  • 707773450239