GL1200 Ltd. and SEI Repair -- Overview The 1985 GL1200 Ltd. and 1986 GL1200 SEI ignition and fuel system, is like no other that Honda has built to the best of my knowledge. This system was only used on these two make and model years, and has some features and functions that were unique to these two models. One of these features is that the ECU (Electronic Control Unit) the black box is located at the back of the machine under the top box. On the Left side of the unit (left as in sitting on the seat) is a series of LED's that is a trouble shooting/warning guide for analysis of ignition problems. The LED's from left to right are labeled, 3 2 1 0 W LED's #3 and #2 are partially covered by the mounting bracket for the ECU, and you have to change the angle that you are looking from in order to see them. When you first turn the ignition key on, and with the "Kill" switch in the run position, the following should happen. The LED's will come on and blink rapidly several times to indicate that they are working, (Look fast, 1 1/2 sec. duration) and the fuel pump will activate for 3 to 4 seconds to pressurize your system. If this does NOT happen, then there are a few things to check before you start thinking that the bike has a major problem. In order they are: * BATTERY Charged and ALL battery cables properly installed tightened, and not corroded. * Main FUSES (Links) (2) installed and not burned out. * The "KILL" switch is made properly The battery cables, and the connections to them, are more important than you might think for several reasons. The first reason is that this system is computer controlled, and voltage is critical. So once again, I am going to say, Make sure that the battery cables are in place, tightened, and NOT corroded. If in doubt, CLEAN or REPLACE the Cable with a new one. From the battery, the 12 Volt source feeds the STARTER RELAY and the has TWO paths that it takes, both are critical. Follow along on the wiring diagram, and component reference diagram. Some of these items are not shown in this simplified drawing. On the right side of the battery, there are TWO fuses that control the system. One of them (30 amp fuse link) feeds the 12 Volt source to the fuse box, fuses # 9, 10, and 11. * Fuse # 9 (15 amp) feeds the source side of the MAIN RELAY (Relay #4). * Fuse #10 (10 amp) feeds the source side of the STOP LIGHT RELAY (#1). * Fuse #11 (10 amp) feeds the source side of the AIR VALVE/PUMP RELAY (#2). The other one (also a 30 amp fuse link) feeds the 12 volt source to the IGNITION SWITCH and fuses # 4, and 5. * Fuse # 4 (10 amp) feeds the source side of the FUEL SYSTEM INDICATOR LIGHT. * Fuse # 5 (10 amp) feeds the source side of the "KILL" switch and the source side of the STARTER button. If the "KILL" switch is made the output of the "KILL" switch feeds the MAIN RELAY COIL,(#4) the "TILT SENSOR, and the IGNITION COILS. If the "TILT SENSOR" is made the MAIN RELAY (#4) is made because the coil is now grounded, and the output of the MAIN RELAY feeds the FUEL PUMP RELAY (#5) source and Relay #5 COIL source it also feeds 12 Volt source to the IGNITION COILS, the SPARK UNITS, The FUEL INJECTOR RESISTOR(s) (and the FUEL INJECTORS) and the 12 Volt source for the ENGINE CONTROL UNIT. (The ECU). Initially the ECU provides the ground signal (for a few seconds) for the FUEL PUMP RELAY, which activates the Fuel Pump to pressurize the system. The 12 Volts delivered to the ECU starts the LED's blinking to indicate that power is being applied to the ECU, and the ECU resets itself (Guess Work Here) to the start mode. Pushing the starter button activates the STARTER RELAY COIL through either the NEUTRAL SHIFT SENSOR, or the CLUTCH BYPASS SWITCH. This sends 12 Volts to the STARTER MOTOR. The starter button also is an additional (temporary) 12 Volt source to the ECU. The Engine starts, (hopefully) and the combination of the NS SENSOR the GL/GR Sensors, The T1, Tw, PBR/PBL, and THROTTLE SENSOR sets up ignition timing, fuel injection, and engine speed. The function of these items are explained more in this chart. IF YOUR ENGINE STARTS, BUT RUNS POORLY, AND YOU HAVE SOME LED'S OPERATING, THEN YOU NEED TO REFER TO THE LED CHART, AND THEN REFER TO THE APPROPRIATE SECTION THAT DEALS WITH THAT SENSOR. IF YOUR ENGINE STARTS, BUT RUNS POORLY, AND YOU DO NOT HAVE ANY LED'S OPERATING, THEN YOU NEED TO REFER TO THE REFERENCE CHART FOR SUGGESTIONS AS TO WHAT TO LOOK FOR. IF YOUR ENGINE DOES NOT START, THEN THE THINGS THAT YOU NEED TO CHECK ARE AS FOLLOWS. * BATTERY CONNECTIONS * MAIN FUSES (Both of then) * SECONDARY FUSES (In Fuse Box) * FUEL PUMP OPERATION * KILL SWITCH * TILT SENSOR * ECU (Engine Control Unit) * WIRING HARNESS ASSEMBLY * SENSORS OPERATION You will need these tools and this equipment to run the checks that you will need to do in the next set of discussions: Your LTD, or SEI Tool Kit. (The fancy one that came with it.) or some Metric wrenches and sockets. Screwdrivers, Allen Head wrenches, and a GOOD RELIABLE VOLT/OHM Meter. Additionally you will also need a Vacumn Pump, and a Fuel Pressure Gauge capabile of reading up to 50 PSI. --------------------------------------------------------------------------- Continue | Table of Contents