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Kinsler_Handbook_#32 December 2017
Kinsler Fuel Injection, Inc, 1834 THUNDERBIRD TROY, MICHIGAN 48084 U.S.A. www.Kinsler.com Phone (248) 362-1145 Fax (248) 362-1032 121 ELECTRONIC FUEL INJECTION BASICS SOME GOOD TIPS 1) Use premium quality race type suppression ignition wire. The type we use has what looks like a tiny coil spring for a conductor. This “spring” design reduces the magnetic flux field surrounding the wire and therefore reduces the amount of electro-magnetic interference (E.M.I.). 2) You can never be too careful with the wiring effort. Through all the years, electrical wire failures have been a prime cause of cars not finishing races, even with just basic electrical systems. Ty-wrap® the wires often so they don’t vibrate and keep them away from the distributor cap and spark plug wires. Use silicone sealer to strain-relief the wires. 3) The ECU must not be subjected to severe vibration or jarring. It is best to mount it on rubber vibration mounts, which we can supply. Some engines shake way too much for the ECU, especially a four cylinder. It’s always safest not to mount the ECU on the engine. 4) The ECU is made up of microprocessor computer circuits that operate on very tiny electric inputs from the sensors on the engine. You can’t be too careful with the wiring in the vehicle : A) The chassis is not an acceptable ground for these systems! Using it as the ground for the ECU has caused many problems with all the brands and types of ECUs. The problem is that any vehicle has points along its electrical systemwithvaryingvoltages, varying resistances, and current surges. By far the safestway tohookup the power supply to any ECU is to run the positive and negative lead all the way from the terminals on the battery. Put a relay in the circuit, energized by the ignition switch so that the ECU will be automatically turned off when you shut off the vehicle. This wiring isolates the ECU from the current surges that pass through the ignition switch. B) Alternators, electric fuel pumps, and other electric devices that seemed just fine before installing the ECU may actually cause electric “noise” to be transmitted through the air or through the wires thus disturbing the functioning of the ECU. Loose ormarginal connections in totallyunrelated electrical items in the car can cause electrical surges that may affect the ECU. Make all the connections as secure as you can. 5) The ECU DOES NOT LIKE HEAT !!! Since it is a computer circuit that is subject to failure from heat, and it is generating it’s own internal heat from it’s circuits, it must be mounted in as cool a spot as you can find. The driver compartment is usually the best location. The better units need to be surrounded by air not exceeding 140 o F while some units are limited to 110-120 o F. 6) Nearly all sensors being used on racing EFI systems are from passenger car systems... they don’t have the vibration or temperature ratings that would be ideal for race vehicles. A few things to do : A) Mount the air temperature sensor in the air intake duct and isolate if from any heat that could be conducted to it from the engine. B) On engines that shake a lot ( just about all four cylinders), replace the sensors often that are mounted on the engine, especially the throttle position sensor... vibration seems to wear its rotating circuit wiper rapidly. C) If the sensor shorts or goes open circuit, the output will be at it’s minimum or maximum value... program these points in the ECU with a “nominal” value so you can keep racing, or at least limp home. D) When using a hall effect sensor for triggering the ECU, be sure to locate it in an area that will not exceed 300 o Fahrenheit, or it will fail. E) Mount all temperature sensors in active areas. Examples: mount the air temperature sensor where air will pass over the sensor tip; mount coolant sensor where there is good coolant flow so you don’t ‘read’ a hot spot. All of the systems are programmed via a serial link from an IBM compatible computer and allow the inputs from the sensors on the engine to be monitored on the screen. Some systems use graphics for ease in programming. Programming software ranges from $300.00 thru $2,000.00 depending on the number of controllable features. The Basic Fueling in any EFI system is controlled by engine RPM and the amount of time each injector is kept open. It is the “open” or “on” time that is varied by all the programming. This is called the “pulse width” and is measured in milliseconds. When the user wants to richen the engine, he places a larger value in the RPM and load sites to increase the pulse width. The entire group of all the numbers is called the “table” or “map” for each of the ECU’s programmable functions. Accel DFI Gen. VII ECU © 2017 Most users are at least a bit intimidated by all the new things to know when first learning to program an EFI system, especially if not familiar with using a computer, but it all falls into place after a bit of practice.
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