Honda CB900F Service Manual page 90

FUEL SYSTEM (Programmed Fuel Injection)
Do not apply commercially available carburetor cleaners to the inside of the throttle bore, which is coated with
molybdenum.
Do not snap the throttle val ve from full open to full close after the throttle cable has been removed . It may cause incorrect
idle operation.
Seal the cylinder head intake ports with tape or a clean cloth to keep dirt and debris from entering th e intake ports after the
throttle body has be en removed .
Do not apply excessive force to the fuel pipe on the throttle body while removing or installing the throttle body.
Do not damage the throttle body. It may cause incorrect throttle and idle valve synchronization.
Prevent dirt and debris from entering the throttle bore, fue l tube and return tube, clean them using compressed air.
The throttle body is factory pre-set. Do not disassemble in a way other than shown in this manual.
Do not loosen or tighten the white painted bolts and screws of the throttle body. Loosening or tightening them can cause
throttle and idle valve synchronization failure.
Do not push the fuel pump base under the fuel tank when the fuel tank is sto red.
Always replace the packing when the fuel pump is removed .
The programmed fuel injection system is equipped with the Self-Diagnostic System described on page 5-6. If the malfunc-
tion indicator lamp (MIl) blinks, follow the Self-Diagnostic Procedures to remedy the problem .
When checking the PGM-FI, always follow the steps in the troubleshooting flow chart (page 5-10).
The PGM-FI system is provided with fail-safe function to secure a minimum running capability even when there is any trou-
ble in the system . When any abnormality is detected by the self-diagnosis function, running capability is secu red by mak-
ing use of the numerical values of a situation preset in advance in the simulated program map. It must be remembered,
however, that when any abnormality is detected in four injectors and/or the ignition and cam pulse generator, the fail safe
function stops the engine from the standpoint of protecting it.
For PGM-FI system location, see page 5-4.
A faulty PGM-FI system is often related to poorly connected or corroded connecto rs. Check those connections before
proceed ing .
For fuel reserve sensor inspection, see section 19.
The vehicle speed sensor sends digital pulse signals to the ECM (PGM-FI unit) for computation. For vehicle speed sensor
inspection, see section 19.
When disassembling the programmed fuel injection parts, note the location of the O-rings. Replace them with new ones
upo n reassembly.
Before disconnecting the f uel tube, release the fuel pressure by loosening the fuel tube banjo bolt at the fuel tank.
Always replace the sealing washers when the fuel tube banjo bolt is removed or loosened.
Use a digital tester for PGM-FI system inspection.
SPECIFICATIONS
ITEM
SPECIFICATIONS
Th rottle body identification
Except California type
GQ34C
number
California type GQ34B
Starter valve vacuum difference 2664 Pa (20 mm Hg)
Base throttle valve for synchronization
No .2
Idle speed
1,200
±
100 min" (rpm)
Throttle grip free play 2 - 4 mm 11/16 - 3/16 in)
Intake air temperature sensor resistance (at 20·C/68"F) 1 - 4 kQ
Engine coolant tem perature sensor resistance (at 20°C/68 "F) 2.3 - 2.6 kQ
Fuel injector resistance (at 20T/6WF)
11.1-12.3Q
PAIR solenoid valve res istance (at 20'C/68'F) 20 - 24 Q
Cam pulse generator peak voltage (at 20'C/68 'F) 0.7 V minimum
Ignition pulse generator peak voltage (at 20'C/68'F) 0.7 V minimum
Manifold absolute pressure at idle 200 - 250 mm Hg
Fuel pressure at idle 343 kPa 13.5 kgf/cm' , 50 psi)
Fuel pump flow (at 12 V) 256 em " (8.7 US
OZ ,
9.0 Imp oz ) minimum/10 seconds
5-2