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The Fuel Shut-Off System was introduced in some 1980 B310 USA models. It leverages the anti-diesel valve to stop the fuel flow during periods of deceleration. This is similar to what EFI systems do. It is only active at higher speeds, namely above 40mph.
1980: All California models 1980: FED A15.MT 1981 CAL, FED, FED.MPG and CAN.MPG models. Canada models did not use fuel-shut off except for MPG (FU Engine) models.
For safety and good performance, the FSOS does not work unless the engine is decelerating.
- Only works when decelerating (vacuum is high AND speed above 40mph)
- Does not work in neutral, so engine will not stop due to lack of fuel
- Does not work when clutch is engaged (so you can blip the throttle)
Components are:
- Anti-diesel valve (solenoid)
- Vacuum valve
- Speedometer speed switch amplifier and relay
- Also used by CAL Mixture Ratio Rich-Lean Exchange System
- Automatic Transmission inhibitor switch
- Manual Transmission Neutral Switch
- Clutch pedal switch
This would be an interesting system to retrofit to older models for increased fuel economy.
Fuel Shut-Off System replaces Throttle Opener.
- Hitach DCH306-67
- Dual-mode spark advance (intake vacuum works at idle, improving fuel economy)
- Double-lead anti-diesel valve
- 16767-H7280 UNIT-ENGINE REVOLUTION A14 FED(KFU) B310 [Engine Rev Switch, 1000-1150 RPM)
- 16024-H7281 THROTTLE SWITCH ASSY A14 FED(KFU) B310 [Throttle Valve Switch]
- 32130-H9011/32130-H9010 EXTENSION ASSY-REAR [unique, but others may work]
- 32006-K2401 SWITCH COMP-NEUTRAL COUPE 5-SPEED(CAL),FED KFU [Neutral Detecting Switch] replaced 32130-H9705 32006-K2400
- 10mph switch in speedometer
Coasting Cut-off
Nissan intoduced a similar system for 1968 USA Datsun Pickup model 520-TU. Call "coasting cut-off", it's main purpose was to reduce unburned hydrocarbons on decelleration. It is described in Nissan "Service Bulletin Vol. 79"
COASTING CUT-OFF PARTS * Datsun 520-TU from 1967 October (1968 model years + 1968-1969 521 with J13) 16010-20610 Hitachi carburetor DCA306-4 * with magnetic valve and accelerator switch 16010-B0412 Hitachi DCA306-4A 16010-B0412 Hitachi DCA306-4BK (ISO) 16328-20600 Vacuum Switch (VS37-1)
"FUEL CUT OFF this vehicle is equipped with a fuel cut off to maintain emissions"
1969 Datsun 521 LTU J13-equipped pictured
Vacuum Switch is just below the gold sticker
The carburetor contains "Solenoid Valve (24D)" and a bolt-on micro-switch "Throttle Switch" and bracket. The solenoid looks like an Anti-diesel Valve, but will be on a non-BCDD, non-auto choke carburetor.
micro-switch
Fuel-cut Valve
[need photo] is in same location as later Anti-diesel Valve
Not to be confused with "Coasting Air Solenoid Valve" (triangle base on Hitachi DAF328)
Not to be confused with Anti-diesel (Fuel-Cut) Valve (Hitachi DCH340):
Not to be confused with a Boost Controlled Deceleration Device (BCDD) Valve:
BCDD starting June 1971 for Datsun 510 USA (same time as auto choke)
Or B.C.D.D. with vacuum control valve
