Technical data

13773-001
73-00
Page 330 Nov 2000
Low Fuel Flow Indication Restricted flow to metering valve. Check mixture control for full
travel.
Inadequate flow from fuel pump. Verify pump pressure, adjust
engine-driven pump. (Refer to
TCM Service Bulletin SID97-3)
High Fuel Flow Indication Restricted flow beyond metering
valve.
Check for restricted nozzles or fuel
metering valve. Clean or replace
as required. (Refer to TCM Model
IO-550 Overhaul Manual)
Restricted recirculation passage in
fuel pump.
Replace engine-driven fuel pump.
(Refer to TCM Model IO-550 Over-
haul Manual)
Fluctuating Or Erroneous Fuel
Flow Indication
Vapor in system, excess fuel tem-
perature.
If not cleared with boost pump,
check for clogged ejector jet in
vapor separator cover.
Air in fuel flow gage line. Leak at
gage connection.
Repair leak and purge line.
Poor Idle Cut Off Fuel flow continues to engine. Check mixture control is in full idle
cut off. Check boost pump is OFF.
If neither, replace manifold valve.
Fluctuating Fuel Flow
Indications
Fuel vapor as a result of high
ambient temperatures
If not cleared with auxiliary
pump, check for clogged vent in
fuel pump vapor separator
cover.
Air in fuel flow gage line. Leak
at gage connection
Repair leak and purge line.
Unmetered Fuel Pressure too
High
Internal orifices plugged Clean internal orifices injector
pump. Refer to Fuel Injection
Service Manual, Form X30593A.
Unmetered Fuel Pressure Drop Relief valve stuck open Repair or replace fuel pump.
Very High Idle And Full Throttle Relief valve stuck closed Repair or replace fuel pump.
Fuel Pressure Present
No Fuel Pressure
Check valve stuck open Repair or replace fuel pump.
Trouble Probable Cause Remedy