LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Land Rover >> 1995 >> Defender 90 >> Repair and Diagnosis >> Quick Lookups >> Technical Bulletins >> Technical Service Bulletins >> Engine Control Systems >> Cold Start Enhancement (19/01/97/NAS)
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Cold Start Enhancement (19/01/97/NAS)

Publication date: 1997-01-17
Reference number: 19/01/97/NAS

COLD START ENHANCEMENT

COLD START ENHANCEMENT

TECHNICAL SERVICE BULLETIN

Reference Number(s): 19/01/97/NAS, Date of Issue:  January 17, 1997

DEFENDER 90 COLD START ENHANCEMENT

Model(s): 1994-95 Land Rover Defender

Group: Emission Control

Bulletin Number: 19/01/97/NAS

Date: January 17, 1997

DETAIL

During previous winters Land Rover has received numerous reports of poor starting of 1994-95 Defender 00 vehicles in extremely cold weather. This condition would arise when a vehicle has been cold soaked overnight in ambient temperatures below 20° F. There may be complaints of long crank time, slow crank speed, or a no-start condition. Upon inspection the engine will appear to be flooded (over fueled). Land Rover has developed the following procedure to correct this condition. All items must be completed in order to improve sub zero starting performance:

These procedures are an extension of the Land Rover Operation Pride concept developed for the Discovery and Range Rover Classic. Each component must be ordered individually but all the parts must be installed for the customer to benefit from the cold start package.

ACTION REQUIRED

Upon customer complaint for the symptoms outlined, perform the specified repairs.

PARTS INFORMATION

PARTS INFORMATION

Part Number Description Qty.
YPG10002 Eyelet (5 qts.)
ERR3340 Oil Filter 1
PRM3654 PROM (3.9 L Defender 90) 1
ERR6087K 1.7KW Starter 1
AMR5911K Positive Battery Cable 1
PRC9224K Negative Battery Cable 1
ERR2926 IACV Housing Gasket 1
Locally Sourced 5W40 or 5W30 Engine Oil (6 qts.) Heat shrink tubing ---

PROCEDURE

Perform the diagnostic procedures and repairs outlined for the repair of poor starting performance.

ENGINE CRANKING

Cranking speed is critical. The major elements determining cranking speed are:

Oil viscosity, battery condition, starter strength, and wiring.

Oil - Change the oil filter and the oil to a 5W40 or W30 grade oil. This is the most important element influencing the engine's ability to crank at an acceptable speed. 5W40 oil is required for temperatures below 32° F (0° C) and is recommended all year. A lighter weight oil dramatically increases the engine cranking speed and improves lubrication at low temperatures.

Starter - Change the starter and the 2 battery leads. A new 1.7 kW starter should be installed in any vehicle that will need to be started at temperatures below -23° C (-10° F). New cables will have to be installed in order to obtain the full benefit of the starter change. The performance of the entire system can be compromised if the various connections are loose or corroded. It is important that all connections be tight and corrosion-free. Apply anti-corrosion wax to connections after they are cleaned and tightened.

FUEL SYSTEM

The correct fueling calibration is essential to provide reliable starting and running of the engine while warming up.

ECM - A new tune has been developed to optimize fueling calibration at temperatures below-23°C (-10°F) This should be installed in all vehicles that will be expected to operate in this temperature range. Use the following work procedure to replace the PROM:

  1. Remove the ECM from right side closure panel on 1994 MY Defender 90/or under R/F seat on 1995 MY Defender 90, and disconnect the multiple connector.
  2. Place the ECM on a grounded anti-static mat. Slip on anti-static wrist cuff and connect spiral jumper lead to the mat. Use longer jumper wire to ground the mat to an electrical conduit or a cold water pipe.
  3. Remove four Torx (T20) screws from the ECM and remove bottom half of cover.
  4. Remove printed circuit board from case and place on anti-static mat.
  5. Locate PROM cover and remove it by grasping with pliers across its width at one end or the other (avoid the center). A rocking motion aids removal. Set cover aside for later use.
  6. Using the PROM removal tool, carefully lift the PROM from its socket.
    NOTE: Be careful not to damage Printed Circuit Board or other components. Store PROM in parts retention area with a completed Warranty Parts Tag.
  7. Remove the new PROM (PRM3652) from its package and insert it into the socket. Make sure all pins are engaged before pressing PROM fully in socket. See Fig 1 . Snap PROM cover in place. If it doesn't fit, recheck PROM for correct installation.
  8. Place Printed Circuit Board in case and reassemble cover. Make sure gasket is in place.
  9. Attach multiple connector to the ECM and perform the following checks:
    1. Switch on ignition. The fuel pump should run for a short period. Listen for any unusual noises such as injectors operating or relays clicking which would indicate a problem.
    2. Observe that the Check Engine" light comes on and then extinguishes during the bulb check. If not, check the multiple connection and if necessary, replace the ECM.
    3. If the vehicle fails steps A or B, recheck the multiple connector pins and socket. If this does not resolve the problem, check that the PROM was installed correctly.

QUALITY-CHECK PROCEDURE

Start the engine and observe the following:

  1. The "Check Engine" light remains out.
  2. Idle speed smoothness is stabilized.
  3. Switch on A/C and note idle speed compensation.
  4. Rev the engine; no misfire should be noted.
NOTE: Replace the ECM if the vehicle fails any part of this procedure.

Otherwise:

  1. Attach a new label.
  2. Install ECM and trim panels.

BATTERY TESTING

Before performing any battery testing or charging operations, the external condition of the battery should be checked for damage, such as a cracked case or leaking terminals. The top surface of the battery and terminals should be clean and free from dirt, acid accumulation and corrosion. A dirty battery cover can form a type of conductor which will permit current movement between posts, possibly discharging the battery if the vehicle is not driven regularly.

HYDROMETER

The measurement of the acid concentration in the electrolyte is referred to as specific gravity of the electrolyte. The measurement of the specific gravity of the electrolyte is an accurate method for determining the state of charge of the battery.

On standard batteries, a hydrometer is inserted into each cell to draw off some of the electrolyte. The specific gravity is then read and compared to the following chart to determine the state of charge of each cell.

BATTERY CHARGE INFORMATION

State of Charge Specific Gravity Open-Circuit Voltage
100% 1.260 2.10
75% 1.230 2.07
50% 1.200 2.04
25% 1.170 2.01
Discharged 1.110 1.95

If all hydrometer readings are low but equal, the battery can be considered chargeable. Once a battery has been charged and the cell readings remain below 1.250 or if there is more than .050 difference between the cells, the battery should be replaced.

LOAD TESTING

Once it has been determined that the battery is in good condition and properly charged, proceed with the load test as follows.

  1. Connect voltmeter and battery load tester across battery terminals according to the manufacturer's instructions.
  2. Remove any surface charge from the battery if the battery has just been charged with a battery charger or the vehicle's charging system. To remove a surface charge, apply a 300 amp load across terminals for 15 seconds. Discontinue load and wait for 15 seconds to allow the battery to stabilize before proceeding with the test.
    NOTE: DO NOT remove surface charge from batteries that have been in storage.
  3. Battery temperature should be estimated by touch and also by the surrounding temperature it was exposed to during the few hours before testing. Select the nearest estimated temperature in the table below and determine the minimum voltage which must be maintained while the battery supplies a specified electrical load.
    BATTERY TEMPERATURE INFORMATION

    Tempera-ture 20°C (70°F) 10°C (50°F) 0°C (32°F) -10C (14°F) -18°C (0°F)
    Minimum Voltage 9.6 volts 9.4 volts 9.1 volts 8.8 volts 8.5 volts
  4. Refer to the following table for the correct load value of the battery being tested. lf the vehicle is not equipped with a Land Rover or authorized Land Rover battery, see the battery manufacturer's specifications for load test values. If load test specifications are unavailable, a good rule of thumb is to apply 48-50% of the battery's cold cranking amperage as a load test value. For example, H the battery in question is rated at 575 cold cranking amps at 0° F (usually printed on battery cover), then the battery should be load tested at 280-287 amps.
    BATTERY CORRECT LOAD VALUE INFORMATION

    Battery Ratings Die-Hard Std/Gold Lucas 072 Lucas GP 664
    Cold Cranking Amps 600 amps/900 amps 590 amps 800 amps
    Load Test Value 293 amps/439 amps 288 amps 384 amps
    Reserve Capacity 115 min/135 min 120 min 200 min
  5. Apply a specified load selected from the preceding table for 15 seconds, then observe voltage while the load is connected. Turn off load immediately after noting voltage.
  6. If the voltage is below the value as specified by the table in step 3, replace the battery. If the voltage equals or exceeds this value, the battery may be returned to service.

ALTERNATOR OUTPUT TESTING

  1. Connect voltage and amperage meter to the vehicle according to the manufacturer's instructions.
    NOTE: For inductive type ammeter, be sure to clip probe around all of the ground cables.
  2. Turn off all accessories and lights. Turn the ignition to the "RUN" position and read the rate of discharge on the ammeter.
  3. Start the engine and adjust idle speed to 3000 rpm.
  4. Voltage reading should be 13.14.4 volts. If readings are excessive, the voltage regulator may be at fault if readings are insufficient, the voltage regulator or alternator may be at fault.
  5. Increase load control to obtain the highest reading on the ammeter scale without dropping voltage below 12 volts.
  6. Turn load control off and return engine to idle.
  7. Add ammeter readings obtained in steps 2 and 5. This is total alternator output.
  8. If total alternator output is within 10% of rated output, the alternator is good.

IGNITION SYSTEM

Electrical resistance increases as the temperature decreases. At the same time, the battery is required to provide more power to operate the starter so the ignition system must be able to deliver a good spark to the cylinder.

CHECK SECONDARY IGNITION SYSTEM

  1. Install coil primary eyelet connectors per Operation Pride Phase 1, article #2-02.
    NOTE: Make sure that plug wires are removed by pulling on the boot and not the cable.
  2. Inspect wires visually. Be on the lookout for cracks, holes, or any damage to the cables or boots. Also check for hardening of the insulator.
  3. Ensure that the wires are fully seated on the spark plug and in the distributor and coil. If any are found to be loose, inspect the loose end for any signs of arcing. Also, ensure that the wire terminal, boot, and mating half connector are clean and reassembled properly. Renew the wire if serious corrosion or damage is evident.
  4. Using a spray bottle containing water, spray the wires with a mist. Look and listen while the engine is running for any signs of the wires arcing.
  5. Attach Test Book with Bear Engine Analyzer to the vehicle.
  6. Attach yellow lead to coil wire and plug into the spot where the eight leads for plug wires on Direct Ignition attach. The green trigger lead attaches to the #1 plug wire. The small wire with the black clip attached to the battery leads must be clipped to the negative terminal of the ignition coil. The cables must be cleaned with brake cleaner for 75 mm on either side of the clip, where the high voltage pick-up and trigger pick-up clip on to the ignition cables.
  7. Perform the secondary ignition test for conventional ignition.

The following results will be observed in a good ignition system:

  • Burn Time should be 0.4 - 2.0 ms.
  • Burn KV should be 1.5 - 2.5 KV.
  • Average KV should be 12 - 17 KV.
  • Snap KV should be 17 - 24 KV.

If any of these readings are abnormal, the secondary ignition is suspect and the following items should be checked:

  • Base Timing - The setting should be as specified in the workshop manual.
  • Condition and gap of spark plugs.
  • Condition of distributor cap and rotor (cracks, dirt, carbon brush condition)
  • Resistance of Spark Plug and Coil Wires - Resistance should be 3 - 6.5 K ohms per foot.
NOTE: These values assume that the fueling condition of the engine is normal.

A high average KV, somewhere around 35 KV, see Fig 2 , (Analyzer reading Chart 1) is an indication of an open circuit on that cylinder. Check for an open circuit in the plug wire or poor connections at the spark plug or distributor.

Variables that Raise Average KV are:

  • High Compression
  • Loose connections (spark plug, distributor, and/or coil)
  • Lean Mixture
  • High resistance in a plug wire
  • Carbon brush missing or broken in distributor cap
  • Sudden load on engine
  • Worn spark plug (gap greater than 0.05 in.)
  • Retarded ignition timing

A very low average KV, around 2-3 KV, see Fig 2 , (Analyzer reading Chart 2) indicates a short circuit in the plug wire or spark plug. Check for short circuit in the plug wire or ground electrode contacting center electrode of the spark plug. Any wires that are out of the above specification or show signs of arcing must be replaced.

Variables that Lower Average KV are:

  • Low Compression
  • Rich Mixture
  • Small spark plug gap
  • Grounded or fouled plug
  • Advanced timing

Finally, if none of the previous checks has shown a failure in the secondary circuit (damage or high resistance), spray only the wire connections with a fine mist of water. Run the engine at idle and snap the throttle. At the same time listen for any signs of misfire. If there is no misfire, the wires should be considered serviceable.

If misfire is detected, locate the misfiring cylinder and renew the wire to that cylinder. Then recheck for misfire. If the misfire is still apparent, other causes should be investigated (i.e. fueling, injectors, compression, spark plugs, distributor cap rotor, crankshaft sensor, exhaust leak, etc.).

CHECK IDLE AIR CONTROL VALVE (IACV) HOUSING

  1. Remove IACV multi-plug.
  2. Remove bolts securing IACV housing to plenum.
  3. Remove gasket and discard.
  4. Examine aperture on housing. See Fig 3 . Faulty castings have an aperture of approximately 8 x 3 mm. (5/16 x 118 in.). Normal aperture should be 11 x 11 mm. (7/16 x 7/16 in.).
  5. Corners marked in Fig 3 are square on faulty castings (normally they should be slightly rounded).
  6. On good castings, the IACV spring is clearly visible but more difficult to see on faulty castings.
  7. If the casting is normal, reinstall casting on IACV with new gasket.
  8. If casting is faulty, remove IACV from housing and file down housing aperture to meet specification as outlined above.

BASE IDLE SETTING

NOTE: Use Loctite 242 on threads before reinstalling.
  1. Turn off all electrical accessories.
  2. Connect an accurate tachometer. DO NOT use vehicle tachometer.
  3. Clamp idle speed control air bypass hose.
  4. Observe idle speed; it must be 525 +/- 25 rpm.
  5. If idle speed is not correct, remove tamper-proof plug from idle speed bypass screw.
  6. Adjust idle speed until correct.
  7. Remove clamp from bypass hose.
  8. Replace tamper proof plug.
  9. If MIL code 48 sets, reset code.
Fig 1: Prom (PRM3652) - Insert Into Socket
G97A58750
Fig 2: Conventional Ignition Systems
G97B58751
Fig 3: Correct/Incorrect Housing Aperture Size
G97C58752

WARRANTY INFORMATION

19.22.89.31: Cold Start Enhancement

Time: 3.9 hrs.

Normal warranty policy and procedures apply.

scientia non olet · About LEMON Manuals