1981/04/09 Caterpillar

Electrical Information For Egr (exhaust Gas Recirculation) Systems On 3208 Truck Engines So Equipped


Reference: "Important: Use Only 12 Volts Direct Current To Boost Start 3208 Truck Engines Equipped With Exhaust Gas Recirculation Systems ", in the April 9, 1980 Engine News.

The reference article tells about the danger of possible injury and/or damage when an electrical current source with a voltage higher than the engine electrical system is used to boost start the engine. The engine electrical system is rated at 12 Volts DC (Direct Current), and the maximum permissible voltage in the system is 15 Volts DC. Any voltage higher than 15 Volts will cause damage to electrical system components, especially the EGR (Exhaust Gas Recirculation) system.

The EGR system has transistors in the cover assembly on the governor and fuel injection pump group. These transistors will give long service life in normal use, but can be easily damaged in any of several ways:

... The use of a different type fuse as a replacement for the original fuse in the cover assembly on the fuel pump. The original equipment fuse has a special design for protection of the transistors, and any other type fuse will not give this protection.
... Any voltage higher than 15 Volts DC in the electrical system, especially if the fuse has been changed to a different type.
... Any contact of disconnected solenoid wires with an electrical ground (either the engine or the truck chassis) while the ignition switch is "ON". This is very important. If the serviceman makes a ground contact for the shortest possible time to check for an electrical spark as a circuit test, the transistors can be damaged. To prevent transistor damage, be sure the ignition switch is "OFF" when the solenoid wires are disconnected.

Caterpillar Information System:

1981/04/09 Clean Electrical Contacts In Exhaust Gas Recirculation (e.g.r.) Switch Group And Cover Assembly Before Installation
1981/04/09 6V3197 Spacer, 6V3041 Tool Group Available For Use During Removal And Installation Of Piston Pin Bearings
1981/04/09 Correct Refill Capacity For Engine Oil
1981/04/09 Cooling System Cleaner Removes Rust And Corrosion
1981/04/09 Two New Oil Filter Assemblies Available; Always Use Correct Oil Filter And Follow Caterpillar Change Intervals
1981/04/09 Special Studs And Nuts Available For Exhaust Manifolds On Engines Used In Heavy Load Conditions
1981/04/09 Correction To Torque Specification For Locknuts On Valve Clearance Adjustment Screws Of Engines Equipped With Jacobs Engine Brakes
1981/04/09 6V4163 Bit And 6V4164 Driver Now Available For Removal Of Bolts For Flyweight Carrier
1981/04/09 Low Engine Temperatures: Install Check Valve
1981/03/06 New Governor Spring Available For Specific Engine Applications
1981/03/06 New O-ring Seal Used In Egr (exhaust Gas Recirculation) Control Has Better Resistance To Heat Damage
1981/03/06 Check Oil Level Carefully To Prevent Operation With Too Much Oil In Engine Crankcase
1981/04/09 Improve Use Of Engine Service Manual Microfiche
1981/04/09 List Of Service Publications
1981/04/09 Check All Settings When Fuel Injection Pump Group Is Installed
1981/04/09 Use 6V4058 Universal Extension To Remove And Install Starter Bolts
1981/04/09 Fuel Pressure Relief Valve Is Shown Inverted (wrong End Up) In Parts Book Illustrations
1981/04/09 6V3150 Engine Pressure Group Gives Direct Indication Of Manifold Pressure
1981/05/12 Crankshaft Failures; New Thrust Plate
1981/05/12 New Tool Makes Glow Plug Wire Removal Easier
1981/05/12 Remove Direct Injection Fuel Nozzles With 6V4061 And 6V4054 Nozzle Pullers
1981/05/12 Larger Valve Springs
1981/05/12 FT1585 Plate Can Be Fabricated For Governor Spring Guide Replacement
1981/05/12 New 6V3060 EGR System Tester Group Available
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