TM-9-2815-220-34 Direct Support Manual for AVDS-1790-2C and AVDS-1790-2D Engines Download

Manifold Heater Tts -Continued l. Remove high tension wire from igniler (spark plug). Position lead wire end t ground for spark gap (1/4") and press healer swilch "on". OT 14.4 Spark Plug Operation: WARNING lligh Voltage I. Remove spark plug, reconnect wire to spark plug, ground plug y lo engine and press healer switch "on". DT M.5 lenoid Valve (s) Operation: 1. Press healer switch intermit- tently "ON" and "OFF" OT 14.6 l. I 2. 3. 4 5. Fuel System Checks: Purge Pump: Disconnect purge pump fuel hose quil.:k discon- nect coupling at enne main fuel backnow valve. llold coupling valve open and op- erate purge pump. Fuel Filler: Disconnect fuel tu between fuel chk \'ah·e e and manifold heater fuel filler and operate purge pump. lenoid Valve and Fuel Filter: Dionnect one fuel tu om engine front solenoid valve out· leL tee, operate purge pump and press heater switch ''ON" and "OFF". Fuel Nozzle Assembly: Disconnect lines and remove nole aem- bly. Reconneel lines to nozzle, (pilion nozzle beside housing) and operate heater system. Return Fuel lenoid Valve and Check Valve: Remove fuel return solenoid outleL tube after the check valve at rear of engine, operate purge pump and pre healer switch "ON" and "OFF". Tobie 2-3. Dtic Tests - Conti nued ation a. Note high tension spark (hol bluish· white) acro gap (lead-to-ground). a. Note high lcnsion spark across spark plug electrodes. a. Note audible "click" or opening and clos- ing valve action (by touch) of both solenoid \"alves (fuel supply and fuel return). a. Note fuel with each firm stroke of purge pump. a. Note fuel flow with each stroke of purge pump. a. With switch in "ON" pition, note fuel flow from tee opening with each purge pump stroke. b. With switch in "OFF" pition nole thal fuel flow slops. a. With switch in "ON" pition, nozzle should have fine conical fuel spray pattern. a. With switch in "ON" posit. ion, note fuel flow om check valve opening. b. With switch in "OFF" pition note that fuel flow slops. TM 9-281 5-220-34 al. High tension spark indicates ignition unit operalion normal. a2. lmproer spark or no spark indicates ignition unit or ignition unil lead is defective. al. High tension spnrk indicates spark plug firing, operation Mrmal. a2. No spark, the s 1 rk plug is defccLive. al. Evidence of action indicates normal solenoid vah•e operation. a2. No audible "click" or action indicates solenoid valve(s) is defective. al. Moderate flow with each stroke indi· cates normal purge pump operation. a2. If flow is not evident, purge pump is defeeth·e, or purge lines are blked or leaking. al. Moderate flow with each stroke indi- cates no in-line filter restriction. Filter satisfactory. a2. No now, or restricted now, indicates in-line filter is plued. al. Fuel flow indicates solenoid valve is operating property and fuel fillers arc satisfaclory. a2. No fuel or restricted now indicates manifold healer filter or fell filte in solenoid valve are restricted or cloed. bl. U fuel now slops, solenoid valve is cl· ing properly. b2. IC fuel now conLinu, solenoid valve is defective (stuck open). al. Fine fuel spray pattern indicates proper nle operation. a2. No spray pattern, stream of fuel, drih· ble or no fuel indicates defective n!2le or plued felt port filters in nzle aembly. al. Merate now indicates solenoid \'alve is operating properly and check valve is opening properly. ✂. No fuel or rtricted now indicates check valve stuck  or felt fil lers in solen oid val ve are restricted o r cloed. bl. H fuel flow stops, lenoid val\'e is cl- ing properly. b2. Jf fuel now continues, solenoid valve is defecth•e (stuck in open position). Change 3 2-31