Couple of questions about wiring in a datalogger.
I was wondering which wire on the coil pack would give an RPM signal and at what voltage. Is it going to be less than 5V?
Also wondered if there was anywhere to get a throttle position voltage, on an 05 car, without fitting an additional sensor?
Cheers
Will.
Coil packs usually consist of two coils, one for each pair of cylinders and when trigured the coil pack fires two cylinders at the same time (the two that share a coil within the coil pack), even though only one cylinder requires a spark, the spark at the other cylinder is wasted (hence wasted spark ignition system). Every two coil, coil pack I have played with has three wirs going to it. The centre wire is a live feed and the two wires either side are connected to 1 of the internal coils each, and the other end goes back to the ECU. When the ECU wants to fire one of the coils, it simply gives one of the two wires an earth, which then fires the coil. So to get to the end of my stupidly long explanation, either of the outside wires on a three wire coil pack should do the trick. To be sure, with the ignition on, but the engine stopped, test for a voltage at all three wires and connect your RPM wire to either of the two wires that has zero voltage.
The TPS will also usually have three wires, one will be a 12v live, one an earth and the third is your signal wire which will vary between 0v and 5v, again, test it with a multi meter with the ignition on to find the correct wire.
Sean…
Cheers Sean,
On the S2 there are 4 wires on top off each plug. There is a picture in this thread. Shift-i
Marc mentions a red/black wire, but I seem to have a red and a black wire.
Re TPS. If the wiring and sensor is the same as on a Celica 2ZZ then the TPS has IIRC 4wires.
Joseph
Hi,
I’ve tracked down the info I needed. Thanks Mark.
The throttle position sensor on the Exige has 3 wires.
Black → GND
Silver → 5V Ref
Green/Yellow → Signal.
So need to splice into the Green/Yellow to get throttle position for the data logger.
RPM available from the red/Black wire on coil one. I originally thought this was a red wire but closer inspection in the daylight shows it is red/black.
Cheers
Will.