Jim_1979 Posted November 4, 2006 Share Posted November 4, 2006 Bought a generic FCD and looking to install it. It has 3 wires. One that goes to the TPS signal wire One that goes to ground One that goes to +5v The earth is easy enough to sort out. The TPS wire is the pin no. 62 on the middle plug B, Black/Yellow wire. What about +5v ?? I don't have a multimeter... so I'm stumped with this one?! Anyone able to help?! Thanks in advance! Jim Quote Link to comment Share on other sites More sharing options...
Steviekid Posted November 5, 2006 Share Posted November 5, 2006 It has 3 wires. One that goes to the TPS signal wire One that goes to ground One that goes to +5v How does that work? Surely you need four wires, another one to go to the ECU? You can get a 12V supply off plug 31, don't know about a 5V though. Quote Link to comment Share on other sites More sharing options...
tDR Posted November 5, 2006 Share Posted November 5, 2006 Why would you need to tap into the TPS signal wire? FCD's typically should have 4 wires: 1 power feed 1 ground 1 to MAP sensor 1 to ECU The last two are concerned with the actual fooling of the ECU to make it think you are making less boost than you actually are, so that it does not cut the injectors (fuel cut) as a safety reaction. Just now the MAP sensor has a wire going from it to the ECU. What you are doing is taking the MAP sensor output by cutting that wire, run the MAP sensor end to the input on the FCD, then connect the FCD output wire to the other end of your cut wire, which is the input to the ECU. What happens then is the MAP sensor outputs a voltage signal, the FCD intercepts it and adjusts it if above a set value, then feeds the modified signal to the ECU as if the MAP sensor was putting out the lower value. So you have: MAP sensor-> FCD -> ECU Where before you had: MAP sensor-> ECU The power and ground wires for the FCD are the same as anything else electrical you install in a car - it needs powered by a 12V source and it needs to be ground. Hope this helps. Cheers, Brian. Quote Link to comment Share on other sites More sharing options...
Jim_1979 Posted November 5, 2006 Author Share Posted November 5, 2006 Map sensor is Turbo pressure sensor (TPS). The FCD I have basically bleeds off a percentage of the signal so the ecu doesnt see 5volts and set fuel cut off. All I need to know is where a +5v is on the ECU. Quote Link to comment Share on other sites More sharing options...
Jake Posted November 5, 2006 Share Posted November 5, 2006 Here you go Jim Quote Link to comment Share on other sites More sharing options...
Jim_1979 Posted November 5, 2006 Author Share Posted November 5, 2006 Cheers mate... but the FCD I have runs off 5v, not 12. Any idea where a 5v feed is? Quote Link to comment Share on other sites More sharing options...
tDR Posted November 5, 2006 Share Posted November 5, 2006 TPS to me is Throttle Position Sensor Does this FCD you're fitting clamp the signal permanently? If so, you're better with one that only clamps when the voltage seen would trigger fuel cut. Not sure where you'll get a 5v feed. Cheers, Brian. Quote Link to comment Share on other sites More sharing options...
Jim_1979 Posted November 5, 2006 Author Share Posted November 5, 2006 yeah... it clamps it permanantly... Possibly need to get a Mulitmeter out me thinks. Quote Link to comment Share on other sites More sharing options...
tDR Posted November 5, 2006 Share Posted November 5, 2006 Fuel cut happens when the ECU sees 4.1v iirc - Likes of the GReddy FCD can be adjusted to only alter the signal above say 4v. The benefit being, you're going to be in a more accurate part of the fuelling / ignition timing map when below that voltage. Quote Link to comment Share on other sites More sharing options...
Jake Posted November 5, 2006 Share Posted November 5, 2006 I still can't see how this FCD could possibly work, what with it having only three wires. Quote Link to comment Share on other sites More sharing options...
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