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| Engine Management Systems - A Few Myths Exploded Why don't GGR like to mention the colour of the injectors used in conversions? If management systems are so clever, why does a change in specification require a reprogrammed chip? Most high powered Cosworth engines use Motorsport injectors & a 3 bar MAP sensor, can I use these with my standard chip? How can I recognise the different management systems? Where are the management systems located in the Cosworths? What is an ECU? Who writes the programs for GGR Chips? My RS 500 has 4 extra fuel injectors fitted to the inlet plenum; can I connect these up to work in addition to the original set? At what boost pressure does the GGR 8 injector system switch on the extra injectors? |
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The Weber-Marelli engine management systems used in the first four models of the Cosworth range of cars are all slightly different. The latest Escort Cosworth uses Ford's own unique EECIV management system, this is a different story altogether! | |
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Why don't GGR like to mention the colour of the injectors used in conversions? | |
The colour of the injectors doesn't really matter! It is important that the injectors used have a sufficiently high flow rate, to enable the correct level of fuel to be supplied. The management chip must also be configured to work with the size of injectors used, otherwise incorrect fuelling and possible engine damage will result. (Please note that there are many different green injectors available, with totally different flow rates, this is another reason why just the colour is not enough!) | |
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If management systems are so clever, why does a change in specification require a reprogrammed chip? | |
Management systems are very sophisticated, but they can only do what they have been told to do. Basically, the fuel & ignition maps are written so that at certain engine speeds & boost pressures, the ignition advance is so many degrees, and the injectors open for so many milli-seconds. Lowered compression ratios, changes in camshaft profiles etc. will require their own unique fuel & ignition settings. | |
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As explained above, the management system just follows instructions. If you use injectors that have essentially double the flow rate of the standard items, you will inject double the fuel required. The MAP sensor is what its name suggests. A Manifold Absolute Pressure sensor. It senses the boost pressure in the engine; this is converted into a voltage signal & sent to the management system. The management system compares this signal to what it has programmed into its chip, calculates the boost pressure, and sets the fuelling & ignition accordingly. If a MAP sensor is used with a different range to the original specification, the management system will incorrectly calculate the boost pressure, and give out the wrong fuel & ignition settings. | |
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The easiest way to distinguish between the early Weber-Marelli management systems is by the colour of the fuel mixture trim screw in the box. On the front face of the management box, where the large wiring loom plug fits, is a recessed hole, with a small plastic screw visible. The early hatchback systems have a yellow screw; Four door cars have a white screw. Also, the Weber-Marelli Level 6 systems have a mounting flange on their front face to fix them into the car. The Level 8 & P8 systems do not have a mounting flange; the sides of the box are smooth. Only the very early P8 systems were fitted with a mixture trim screw, but as an extra check, the Level 8 systems have a red or green sticker on one of the covers, this will have WD48.08 printed on it. P8 systems have a white sticker, and this will read IAW48/P8. | |
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The two-wheel drive Sierra Cosworths have a blanking panel in the dashboard above the glove box. Behind this panel, you will find the relevant Weber-Marelli management system. On the 4 door cars, the ABS computer is fixed to the top of the engine management system, don't take the wrong one out! On the 4 X 4 Sierra Cosworths, the management system is revealed if the glove box is removed from the dashboard. The Escort Cosworth has the management fixed to the A post, in front of the passenger seat. To uncover the management system, remove the plastic cover below the glove compartment, and you should see either a Weber-Marelli P8, or Ford EECIV management system. | |
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The ECU is another name for the engine management system. ECU stands for Engine (or Electronic) Control Unit. | |
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We do! Although we are agents for after market chips that we fit to many other cars, we make our own management chips for the Cosworth range of cars. With our in depth knowledge of them, and their engine requirements, we have a close understanding of exactly what is required. Our conversions for the small turbo Escort Cosworth use the same module system to connect to the ECU as we would for any EECIV equipped car, but the programming we use was developed exclusively by us for the Escort Cosworth. | |
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No, not simply! The extra rail of injectors was fitted to the RS 500 road car to allow for the additional fuelling requirements of 540+ BHP touring cars. (If you follow the wiring loom from these injectors, you will find that it terminates in a plug hidden below the battery tray!). We are able to make 8 injector conversions using the RS 500 (or Escort Cosworth WRC) hardware, and any Weber-Marelli management system from level 6 onwards, (with relevant hard & software modifications). With this system we can supply the correct levels of fuel that is required for high power outputs, (by using two injectors per cylinder), but give excellent low speed driveability & good exhaust emissions at reduced load conditions where the engine will run on only 4 injectors. | |
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At what boost pressure does the GGR 8 injector system switch on the extra injectors? | |
It isn't that simple. To give ideal fuel atomisation, and a seamless transition between 4 & 8 injector operation, the engine management system will switch to 8 injector operation once the injector opening time reaches a predetermined level. This will mean that this takes place at different engine speeds & different boost pressures, depending on the overall conditions. | |
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