Technical   

EFI Cold / Hot Idle Speed Adjustment

Magnetti-Marelli EFI Cold/Hot Idle Speed Adjustment 
Submitted by: Brian P.   2-11-2005

 

This is the procedure I recently followed to adjust the cold and hot idle speed on my Magnetti-Marelli (M-M) equipped '99 FLHTCUI. This fuel injection system was offered on 99-01 EFI equipped Touring motorcycles as well as Softail models thru 2000.

 

The procedure makes use of the H-D EFI Harness Breakout Box, which I bought off E-Bay.


1. Start engine, allow to warm fully (ET sensor voltage < 0.20vdc).
2. Unplug ISC connector, and record TPS voltage.
3. Shut off engine.
4. Turn on ignition, and turn warm idle screw counter-clockwise until throttle plates are completely closed. Record TPS voltage, and turn off ignition.
5. R&R TPS screws with 4mm X 12 screws with internal hex. Much easier to torque using a hex wrench rather than a vise grips :-)

Note: I had to go find the proper screws... so in the mean time the
engine had cooled.

6. Turn on ignition, rotate TPS to adjust TPS voltage to 0.250vdc. An internet H-D tech site had recommended the range of 0.225vdc(lean) - 0.275vdc(rich). So I chose the middle value.
7. Turn warm idle screw clockwise to set the TPS voltage to that from Step 2.
8. Turn ignition off, and plug in ISC connector.
9. Start engine and allow to warm fully.
10. Unplug ISC connector, record TPS voltage and shut off engine.
11. Turn on ignition, and turn warm idle screw counter-clockwise until the throttle plates were closed. Verify the TPS voltage was still 0.250vdc (it was!).
12. Turn warm idle screw clockwise to set the TPS voltage to that from Step 10.
13. Start engine and adjust the warm idle screw until the idle speed is 1100rpm. Shut off engine.
14. Plug in ISC connector, and turn ignition on, then back to off.
15. Unplug ISC connector, start engine and allow to warm fully.
16. Adjust cold idle screw until idle is at ~1600rpm. (I had to
turn off engine between adjustments, so I could rotate the throttle,
to expose the cold idle screw for adjustment).
17. Shut off engine, and plug in ISC connector.
18. Start engine and verify the engine was fully warm.
19. Check warm idle speed. ( I had to make a small adjustment).
20. Turn off engine and pull both the 5a and 15a fuses.

I then waited for about 2 hours and continued ...

21. Repeated Steps 18-20. (I had to make another small adjustment).

I then waited for about another 2 hours and continued ...

22. Repeated Steps 18-20. (This time no adjustment was necessary).
 

23. Done!!

 

 

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