FOREWORDT h is su p p le m e n ta l m a n u a l is d e sig n ed to p ro v id e dealer service p e rso n n e l w ithin fo rm a tio n o n d ia g n o s in g , m a in ta in in g a n d servicing th e diesel fuel in je c tio nsystem s u sed in C h e v ro le t p assen g er cars a n d lig h t-d u ty tru c k s e q u ip p e d w ithdiesel engin es.W h e n re fe re n ce is m a d e to a sp ecific to o l, n u m b e r o r b r a n d n a m e , a n e q u iv a le n tp ro d u c t m a y be u se d in p lace o f th e re c o m m e n d e d item .A ll in f o r m a tio n , s p e c ific a tio n s a n d illu stra tio n s c o n ta in e d in th is m a n u a l areb a se d o n th e latest p r o d u c t in fo r m a tio n a t th e tim e o f p u b lic a tio n . T h e right isreserv ed to m a k e p ro d u c t o r p u b lic a tio n ch a n g es, a t a n y tim e , w ith o u t n o tic e.P o rtio n s o f th is m a n u a l w ere p ro d u c e d w ith th e aid o f S ta n a d y n e In c ., D ieselS ystem s G ro u p ; L u c a s CAV, a div isio n o f L u c as In d u strie s, In c .; a n d D iesel K ikiU .S .A . C o ., L td .

CONTENTSS E C T IO N 1 Diesel Fuel Familiarization. . 1-1SEC T IO N 2 Stanadyne Injection Pumps. . 2-1SE C T IO N 3 Lucas CAV Injection P u m p . 3-1SE C T IO N 4 Diesel Kiki Injection Pumps . . 4-1SEC T IO N 5 Fuel Lines and Nozzles. 5-1SEC T IO N 6 Glow Plug Systems. 6-1SECTIO N 7 Injection Pump Diagnosis. 7-1A-l

SECTION 1DIESEL FUEL FAMILIARIZATIONVISCOSITYDiesel fuel covers a broad group of petroleum-basedfuels ranging from crude oil to kerosene. Depending on theengine and its operation, these fuels will burn in a dieselengine. The m ajor difference in gas engines and dieselengines is in fuel source, compression ratio and fuel-air mix.(Fig. 1-1)Viscosity is an im portant physical property o f a dieselfuel affecting injection pum p internal leakage and lubrica tion and injector lubrication and atom ization.CompressionRatioFuelSourceFuel-Air Mix(intake)GasolineEngines8:1Carburetedair-luel mistDieselEngines20:1Injectedair onlyFig. 1-1Because o f their design and use, Chevrolet dieselengines use a narrow range o f diesel fuels. These fuels arerated at N o. 1-D, N o. 2-D and W interized o r BlendedNo. 2-D.A characteristic o f diesel fuel rating is Pour Point andC loud Point. P araffin or wax is a com ponent o f diesel fuel.T he Cloud Point represents the tem perature when the wax indiesel fuel begins to crystalize and separate from the fuel.T he P o u r Point represents the tem perature when the waxcrystals interlock and fuel cannot be pum ped. The fuel isheld in suspension like a sponge holds water.No. 1-D fuel has the lowest cloud point and pour point( - 2 0 F / - 4 0 F ) . N o. 2-D has a higher cloud point andpour point (20 P /0 F ). Blended or winterized No. 2-Dvaries between the two based on the blend.Chevrolet recom m ends N o. 2-D whenever ambient(outside) tem peratures are above 20 F. During cold weatherm onths, N o. 1-D should be used. If blended or winterizedNo. 2-D is available, it can be used instead o f No. 1-D.(Fig. 1-2)Rated FuelAmbient TemperatureAbove 20 FNo. 1-DNo. 2-DBelow 20 FApproximatelyCloud Point (-20 )Pour Point (-40 )ApproximatelyCloud Point (20')Pour Point (0 )Blended No. 2-DCloud Point (Varies)Pour Point (Varies)Fig. 1-2DIESEL FUEL CO NDITIONERSA num ber o f diesel fuel conditioners o r m odifiers arecommercially available. Chevrolet does not recommendtheir use in cars and light duty trucks. A lso, the practice o fmixing unleaded gasoline with diesel fuel to reduce cloudp o in t/p o u r point is not recom m ended, regardless o f pre vious inform ation that suggested it.The minimum viscosity is limited by the need foradequate injector and injection pum p lubrication. Lowerviscosity fuels are thinner and therefore will cause a higherrate o f internal pum p and injector leakage and injectordribblings which can lead to loss o f power o r smokeproblem s.Since viscosity influences the size o f the fuel droplets, itgoverns the degree o f atom ization and penetration o f thefuel spray. These are m ajor factors in obtaining sufficientmixing o f fuel and air essential for proper com bustion. If theviscosity is too high, the fuel droplets will be to o large forproper mixing and poor com bustion will result. A lso, thedroplets may strike the relatively cold cylinder wall and failto burn. If the viscosity is to o low, the fuel spray will nottravel across the com bustion cham ber and the poor mixingwill result in im proper com bustion. P oor com bustion resultsin loss o f power and excessive exhaust smoke.CETANETechnicians should be aware o f cetane ratings for dieselfuel. Cetane ratings should not be confused with octaneratings for gasoline. Cetane can be thought o f as the ignitionquality o f diesel fuel. Generally speaking, the higher thecetane rating, the better the ignition quality. A high cetanerated fuel ignites quickly with short delay o r lagging.Conversely, a low cetane rated fuel will take m uch longer toignite, and may cause excessive knock and roughness.T he diesel engines currently used by Chevrolet are forthe most part insensitive to cetane ratings, due to the use o fglow plugs for a starting aid. However, the consistent use o fa high cetane rate diesel fuel will aid in the prevention o fengine knock.FUEL T R A N SF E R ANDFILTERING SYSTEMT here is little difference in the fuel tank and fueltransfer system between diesel and gasoline cars and lightduty trucks. Tank location and filler neck construction isessentially the same. O ne difference is in fuel tank caps. Thediesel fuel cap has a two-way valve which allows built up hotair to bleed o ff. It also prevents fuel spills in the event o f arollover. This cap is not interchangeable with gasoline caps,although the gasoline caps will fit the filler neck o f the dieselfuel tank.T he fuel tank pickup unit is somewhat different. Awater sensor, m entioned earlier, is included on m ost units. Asaran filter o r mesh sock is fitted to the end of the pickuptube. This sock filters large particles from the fuel andstrains m ost o f the w ater out o f the fuel. (Fig. 1-3)T he sock can becom e clogged when diesel fuel coolsbelow the cloud point. A check valve at the to p o f the sockopens when the sock is clogged, allowing fuel to pass. If thefuel level drops below the check valve opening, a no s ta rt/

“run” or “start” position. The ground circuit is completedthrough the pump mounting bracket or through a lead wireto the threaded screw. The mounting surface must be cleanand tight for proper pump operation. Maximum operatingcurrent is 3.0 AM PS. At the pump’s maximum pressure, itwill shut off. It will again turn on at it’s minimum pressure.The pump is mounted to a stud bolt on the left bank o f theengine. (Fig. 1-5)NOTE: No external mechanical or electric fuel pump isneeded on the 2.2 or 1.8 liter engines, since the supply pumpin the injection pump assembly is adequate. There ishowever, a hand-operated priming pump incorporated in thefuel separator on the 2.2 and 1.8 liter engines.Fig. 1-3 Fuel Tank Pick Up Unitout o f fuel condition will occur. Therefore, drivers mustkeep at least a quarter tank of fuel in the vehicle duringwinter months.NOTE: The LUV truck is not equipped with a checkvalve at the sock on the fuel pickup unit.FUEL PUMPSFig. 1-5 Electric Fuel PumpFuel pumps or fuel lift pumps draw fuel from the fueltank and pump it into the fuel injection system. Fuel pumpsmust keep fuel flow constant when the engine is running.Chevrolet uses two types o f pumps; a conventional mechanical/diaphram type and an electric type.FUEL FILTERSFuel filters strain contaminants from the fuel prior tothe fuel reaching the injection pump. All diesel engine carsand light trucks have a primary fuel filter. The 6.2 liter dieselengine also has a secondary filter.The mechanical/diaphram type is found on the 6.2 and5.7 liter diesel engines. They are located on the front, lowerright side o f the block. The 6.2 liter pump is driven by aneccentric lobe on the camshaft through a pushrod. The 5.7liter pump is driven by a lever o ff the crankshaft. (Fig. 1-4)The primary filter for the 6.2 liter engine is mounted tothe cowl. A drain petcock is located on the top and bottomo f the filter. Opening these petcocks will drain any wateraccumulated in the filter. A short length o f hose is attachedto the lower petcock to direct fluid away from the enginecompartment.The electric pump is used on the 4.3 liter engine. Itreceives battery current anytime the ignition switch is in theFig. 1-6 Stanadyne Fuel Filter1-2

The secondary fuel filter for the 6.2 liter engine islocated rearw ard o f the fuel injection pum p. Fuel flowsfrom the prim ary through the fuel pum p to the secondaryfilter. The secondary filter further guards against contam i nants entering the fuel injection pum p.The 5.7 and 4.3 liter engines share similar prim ary fuelfilters. They have a m icronic paper element to straincontam inants and are bracket m ounted to the intakem anifold, just aft o f the air crossover. (Fig. 1-6)T he fuel filters for the 2.2 and 1.8 liter engines have awater separator included in them. There is also a replaceablefilter element in the unit. The filter is m ounted on the rightfender wall o f the engine com partm ent .N O TE: Check the m aintenance schedule in the ow ner’sm anual for replacem ent intervals o f all fuel filters.pum p, the sensor sends a signal to the appropriate indicatorlamp in the instrum ent panel. W hen the lam p is lit, the watermust be purged from the system.To drain the water from the separator, perform thefollowing steps:1. Unscrew the drain valve on the separator about sixturns,2. Place a container under the drain hose to catch the waterand fuel.3. Push down a num ber o f times on the prim ing button atthe to p o f the separator unit. (Fig. 1-7)4. W hen clear fuel begins to flow , the w ater has beenpurged from the filter.5. Stop pushing the priming button and close the drainvalve.6. Pum p the prim ing button until resistance is felt. Thispurges air from the system.WATER IN FUELWater exists in diesel fuel. By law, .5% o r !/i o f 1% o fwater by volume is allowable in diesel fuel. Such smallQuantities o f w ater are harm less to diesel engines and the fuelinjection system. However, larger am ounts o f water have thepotential for dam aging the fuel injection pum p.W ater in diesel fuel tends to accum ulate in refinerystorage tanks, tanker trucks, service station storage tanksand on-car fuel tanks. Every time diesel fuel is transferredfrom one tank to another, it has the potential for picking upm ore water. This does not mean every tim e a custom er fillsthe fuel tank that water is being pum ped in, only that it canand does happen.Water in diesel fuel appears in tw o states, as ice crystalsand as a liquid. W ater in these form s is referred to as free anddispersed and as dissolved, respectively.M ost diesel fuels will have some dissolved water ormoisture. This small am ount o f m oisture remains insuspension in the diesel fuel and will pass harmlessly throughthe fuel injection system.NOTE: A water in fuel sensor is also incorporated onthe fuel pickup unit in the fuel tank o f Chevettes. This sensorwarns the driver o f large quantities o f water in the fuel tank.W hen this sensor is activated, the w ater in the tank must bedrained.The w ater th at accum ulates is another matter. Sincewater does accum ulate in fuel tanks, Chevrolet has includeda Water-In-Fue! Indicator system on all diesel engine carsand light trucks. This system incorporates a water sensor onthe fuel tank pickup unit. (Fig. 1-3). W hen a certain am ounto f water is present in the fuel tan k , the sensor activates aW ater-ln-Fuel light in the instrum ent panel. The dieselengine Chevette and LUV truck has an additional Water-lnFuel indicator in the fuel filter,ALTERNATE WATERREMOVAL PROCEDUREG EN ER A L SER V IC EWATER REMOVAL PRO C ED U R ES1.8Liter Chevette/2.2 Liter LUV TruckThe water separator incorporated in the 1.8 and 2.2 literdiesel engines is p art o f the fuel filter. It is m ounted to thefender wall, under the hood and next to the battery. Theseparator contains a sensing switch at the bottom o f the unit.W hen the am ount o f water in the fuel reaches a pre determ ined level, before it is pum ped into th e fuel injection1. Disconnect the fuel return line from the fuel injectionpum p.2. Connect a pum p or siphon to the fuel return line andsiphon the fuel into a suitable container.3. W hen all water is rem oved, reconnect the fuel returnline to the injection pum p.NOTE: A drain plug is incorporated in the fuel tank ofthe LUV truck. To drain the fuel tank, place a suitablecontainer beneath the tan k and remove the drain plug. Whenall water is removed, replace the drain plug.C A U TIO N : Never drain diesel fuel in an open con tainer, due to the possibility o f fire or explosion.6.2 Liter Light* Duty TrucksThe w ater-in-fuel sensor for Chevrolet Light-D utyTrucks with the 6.2 Liter diesel engine is located o n the fuel

WATER REMOVALpickup unit in the fuel tank. It operates on the same principleas the Chevette water-in-fuel sensor.Fuel Tank—To rem ove w ater from fuel in light-duty trucks,perform both o f the following procedures. Refer to Fig. 1-8for prim ary filter location.1. Park vehicle in a relatively level attitude. The water pickup is in the approxim ate center o f tank.2. Connect siphon hose to the petcock (drain