BJ40 help (3b high idle ) - Pirate4x4.Com : 4x4 and Off-Road Forum

Klasick68 · 08-13-2007, 07:07 AM

Does anyone know what might cause a 3b to idle verry high? (throttle cable is not sticking, idle screw hasnt been touched, throttle plate is damn near closed) I checked the two ported vac lines from above the throttle plate to the pump, and when I block off the port on the outboard side (larger of the two) the idle drops to normal. Blocking off the inboard side port will increase engine speed. Since it seems that the balance between these two ports controls the pump that it should die completely when the outboard port is blocked. Does anyone have an exploded view of the pump for a 3B ?(looking to confirm that the pump is controled in the manner that I suspect it is) Thanks for any help, srry for the newb question.

Stupid frnch jackasS · 08-13-2007, 10:18 AM

the pressure difference controls the injection volume indeed. The high idle, and slow return to idle symptoms usually indicate a porous/ cracked governor diaphragm.

Klasick68 · 08-13-2007, 07:06 PM

Thanks for the help, that fits with the random high idle / slow return to idle after sitting for 6 months.
Thanks again
Dan Hinckley

08-13-2007, 07:07 AM	#1 (permalink)
Klasick68 Registered User Join Date: Feb 2002 Member # 9763 Location: Wentworth NH Posts: 234	BJ40 help (3b high idle ) Does anyone know what might cause a 3b to idle verry high? (throttle cable is not sticking, idle screw hasnt been touched, throttle plate is damn near closed) I checked the two ported vac lines from above the throttle plate to the pump, and when I block off the port on the outboard side (larger of the two) the idle drops to normal. Blocking off the inboard side port will increase engine speed. Since it seems that the balance between these two ports controls the pump that it should die completely when the outboard port is blocked. Does anyone have an exploded view of the pump for a 3B ?(looking to confirm that the pump is controled in the manner that I suspect it is) Thanks for any help, srry for the newb question. __________________ 68 1200, 440/727/205, 60F 14B

08-13-2007, 07:06 PM	#3 (permalink)
Klasick68 Registered User Join Date: Feb 2002 Member # 9763 Location: Wentworth NH Posts: 234	Thanks for the help, that fits with the random high idle / slow return to idle after sitting for 6 months. Thanks again Dan Hinckley __________________ 68 1200, 440/727/205, 60F 14B

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08-13-2007, 10:18 AM	#2 (permalink)
Stupid frnch jackasS Registered User Join Date: Feb 2002 Member # 10010 Location: in your sisters ass Posts: 1,891	the pressure difference controls the injection volume indeed. The high idle, and slow return to idle symptoms usually indicate a porous/ cracked governor diaphragm.