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detailed_procedures_for_troubleshooting 2013/10/26 12:33 current
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 +__**Detailed Procedures for Troubleshooting  - M151A2**__
 +(Use in conjunction with troubleshooter)
 +----
 +**Batteries flat**
 +  * check electrolyte levels, top up as needed
 +  * charge batteries overnight
 +  * if batteries will not hold charge - replace
 +----
 +**Terminal(s) loose or corroded**
 +  *note the correct hook-up of battery cables and clamps to facilitate correct re-connection later
 +  *remove battery-to-body cable at battery #1 terminal
 +  *clean around battery post and terminal clamp with fine emery paper or non-metallic scourer
 +  *apply thin wipe of vaseline or grease to post and clamp
 +  *repeat procedure with all other posts and clamps
 +  *reconnect in correct order
 +  *tighten clamp bolts moderately - do not over-tighten
 +
 +----
 +**Poor earth connection  - battery to body**
 +  * remove battery-to-body cable at body (on inner wall of battery-box)
 +  * check cable for continuity, check covering for integrity
 +  *clean around retaining bolt and terminal with fine emery paper or non-metallic scourer
 +  *apply thin wipe of vaseline or grease
 +  *reconnect cable to body - ensure that star-washer is present - tighten bolt securely
 +
 +----
 +**Starter dead**
 +  *remove transmission cover
 +  *remove starter
 +  *check for obvious faults or damage
 +  *replace as necessary
 +
 +----
 +**Fuel pump diaphragm faulty**
 +  *symptoms are:- oil smells of fuel / oil unusually thin / sudden low oil pressure / sudden blue smoke
 +  *disconnect fuel and vent pipes from fuel pump
 +  *remove fuel pump from engine block
 +  *manually operate cam
 +  *check for signs of fuel leaking into cam area
 +  *diaphragm can be checked by removing pump top but replacement diaphragm is not available
 +  *replace complete pump as necessary
 +
 +----
 +**Pump operating arm broken**
 +  *replace complete pump as necessary
 +  *remove any broken parts from block
 +
 +----
 +**Fuel pipes collapsed-crushed-blocked**
 +  *visually inspect hoses and lines for kinks or flattening
 +  *remove cap from fuel tank
 +  *with assistant listening at tank, attempt to blow back down fuel line into tank
 +  *listen for bubbles at tank
 +  *rubber hoses are prone to swelling inside - replace as needed
 +
 +----
 +**Fuel Tank clogged**
 +  *remove fuel tank cap and gauze fuel filter from fuel tank neck
 +  *feel inside tank for dirt, grit, rust flakes
 +  *remove drain key under bottom of tank and collect fuel and contamination
 +  *filter the removed fuel and replace in tank
 +  *repeat draining & filtering operation until fuel runs clear from tank
 +  *remove fuel tank access plate and clean fuel pickup filter - blow out with compressed air
 +  *if tank is heavily contaminated, remove from vehicle and clean thoroughly
 +
 +----
 +**Incorrect type Fuel Tank Cap**
 +  *non-vented tank caps will cause vacuum in pre-emission tanks.
 +  *ensure cap is correctly matched to tank
 +
 +----
 +**Fuel Cap Vent-valve - Closed position or faulty**
 +  *inspect vent-valve in tank cap (if pre-emission cap)
 +  *ensure valve is set to Open
 +  *replace cap if valve damage evident
 +
 +----
 +**Fuel filter at carb**
 +  *remove filter
 +  *blow filter from threaded end (do not use probes or wire)
 +  *blow in direction of fuel flow - check for restriction of flow
 +  *renew filter if necessary
 +  *when reinstalling, avoid damaging carb - do not over-tightening filter (make sure the 30 degree brass fitting is installed first)
 +
 +----
 +**Coil failure**
 +  *coil tests are not always conclusive - an intermittent coil fault is difficult to identify
 +  *replace with a KNOWN good coil
 +  *ensure that wires to coil are not pinched when distributor cap is re-installed.
 +
 +----
 +**Ignition Points closed-dirty**
 +  *remove points and clean with fine grade emery paper
 +  *ensure point faces are flat and clean
 +  *reinstall points and turn crankshaft clockwise until distributor cam lobe operates points
 +  *re-set points gap to between 0.017" to 0.022"
 +
 +----
 +**Solid State module failed**
 +  *replace with known good module (Prestolite and Swiss Controls modules are NOT interchangeable)
 +  *if module not available, replace module with breaker (points) system and condenser
 +
 +----
 +**Rotor loose**
 +  *twist rotor back and forth gently
 +  *check for loose fit on distributor cam
 +  *ensure rotor retaining spring plate (in base of rotor arm) is in place
 +
 +----
 +**Tower Segments in Distributor Inner Cap corroded**
 +  *check inside of inner (plastic) cap for burnt tower segments
 +  *check for cracks and track-lines between towers
 +  *replace inner cap as necessary
 +
 +----
 +**Contact spring and carbon contact in centre of inner cap missing - damaged**
 +  *replace inner cap as necessary
 +
 +----
 +**Faulty or failed in-line capacitor**
 +  *remove 4 screws at Acorn nut on distributor
 +  *slide out capacitor
 +  *test for continuity
 +  *replace capacitor if necessary
 +  *by-pass faulty capacitor with insulated wire as a short-term expedient
 +
 +----
 +**No power to distributor**
 +  *switch on ignition
 +  *check for live feed to distributor where wire enters Acorn nut
 +  *repair / replace wire if faulty, frayed or broken
 +
 +----
 +**Loose push-rods**
 +  *rotate crankshaft clockwise
 +  *when both valves are closed, check valve clearance
 +  *adjust as needed
 +
 +----
 +**Bent push-rods**
 +  *remove and replace
 +  *attempting to straighten push-rods is usually unsuccessful
 +
 +----
 +**Dislocated push-rods**
 +  *slacken valve tappet adjuster
 +  *relocate push-rod in adjuster
 +  *tighten adjuster
 +  *rotate crankshaft clockwise
 +  *when both valves are closed, check valve clearance, adjust as needed
 +
 +----
 +**Cam lobe damage**
 +  *rotate crankshaft clockwise
 +  *watch each valve and push-rod rise and fall
 +  *if any fail to rise and fall, or if movement is significantly less than others, suspect damage to cam-lobe face
 +
 +----
 +**Worn piston rings**
 +  *to determine whether the low compression is valve or ring related, remove each spark plug
 +  *crank engine and test each cylinder with gauge
 +  *write down each cylinder reading
 +  *pour one eggcup full of clean engine oil into each cylinder via the plug-hole. Allow to settle
 +  *crank engine and test each cylinder with gauge
 +  *if PSI reading has increased, piston rings are worn
 +  *if reading is unchanged, assume valve problems
 +
 +----
 +**Burned valves**
 +  *See test above
 +
 +----
 +**Head gasket blown between cylinders**
 +  *remove each spark plug
 +  *crank engine and test each cylinder with gauge
 +  *write down each cylinder reading
 +  *if two adjacent cylinders show a low reading, assume head gasket has failed between cylinders
 +
 +----
 +**Distributor - Rotor alignment** 
 +  *mark lower body of distributor with white paint / tippex to indicate approximate number and location of each spark-plug tower (firing order is 1,3, 4, 2)
 +  *remove distributor cap
 +  *rotate crankshaft clockwise to align notch on crank pulley with pointer on engine timing case. Ensure both valves on cylinder #1 are closed. If not, rotate        crankshaft clockwise 180 degrees
 +  *if tip of rotor arm does not align with painted mark for cylinder #1 on distributor lower body, but is close, slacken distributor clamp-bolt and rotate distributor body slowly to align
 +  *if tip of rotor arm points to other painted marks, then spark-plug leads were attached to distributor cap in an incorrect firing order
 +  *remove leads from cap and re-attach to match correct firing order
 +  *if tip of rotor arm points to painted mark for cylinder #4, then distributor has been installed 180 degrees out
 +  *remove distributor, rotate shaft 180 degrees and re-install in engine
 +
 +----
 +**Carburettor self-flush**
 +  *feel under base of carburettor at lowest point (fuel bowl)
 +  *locate carburettor hexagonal drain bolt (on bottom of carburettor fuel bowl)
 +  *remove hexagonal bolt to flush fuel / dirt from carburettor
 +  *dry up any spilled fuel
 +  *re-install bolt and tighten moderately. Do not over-tighten.
 
detailed_procedures_for_troubleshooting.txt · Last modified: 2013/10/26 12:33 (external edit)
 
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