Grounds

You need exactly the same grounds as the RSX. These grounds are not optional; they are all mandatory.

There should be a large ground strap between the transmission and the car body. The purpose of this ground is to take care of the large current drawn by the starter motor. Keep the ground fairly short and go to the chassis. The stock transmission has a bracket which has an attachment point, otherwise you can use one of the 8mm case bolts. Do not use the bolt that holds in the reverse idler shaft (as I have seen people do). It should be a fairly short cable. Don't go to the battery with this cable.

The next ground is on the right hand engine mount. Without stock RSX mounts, you can go from the chassis to a bolt on the timing cover. On an EG, DC or EK I prefer to go straight to the battery negative strap attachment point (see below). This does not need to be a very thick wire.

The last ground is from the wiring harness to the engine. Normally it bolts to the manifold - but almost everyone is aware that it needs to be moved. The valve cover stud works. I prefer using an unused 6mm bolt on the end of the cylinder head (doesn't work on the K20Z3 and K24 heads). If you want you can make a wire which runs from the battery to the timing cover and then to this ground point - it doesn't need to be very thick. This is as many grounds as you need - any more is a waste of time and money.

With all grounds you need to remove the paint from under the wire - grounds will not work if the current has to flow through a bolt.

Finally, what you can do with the car running is to put your multimeter into mA current mode, and measure current flows between the battery negative terminal and all your ground points. There should be no more than a few mA current flow, otherwise you have a high resistance somewhere. The current flow method is more accurate than measuring a voltage drop or DC resistance.

EG/EK/DC Battery and Alternator Wiring

With these chassis care must be taken when wiring the alternator and starter motor so that connection resistance does not cause an excessive voltage drop either to the starter motor or alternator.

There are three cables which are needed:

• Starter motor.  This needs to be a unbroken cable which runs from the battery to the starter motor terminal. Do not solder or crimp wires together, nor attempt to connect to the stock RSX wiring harness positive battery terminal - this will result in unacceptable resistance.
• Alternator. This is a smaller gauge cable which runs from the stud on the alternator to the under hood fuse box (it goes to front terminal on the fuse box). Again, it should be an single, unbroken, un-crimped wire.
• Battery cable. This runs from the battery positive terminal to the under hood fuse box. It goes to the second terminal on the fuse box.

Battery Relocation

Do not relocate the battery. There is always enough room in the stock location for an AGM battery, and never a pressing need to relocate the battery.

Relocating the battery inevitably causes problems with excessive voltage drop. There are two very common problems:

• There should be two cables from the positive terminal of the battery - one to the under hood fuse box and another to starter motor. Almost all battery relocations replace this with a single cable, which joins onto the normal battery positive terminal. There are two problems with this: 1) There is now a join in the cable from the battery to the starter motor (and also the other cable to the fuse box). 2) The cable to the fuse box needs to go to the battery positive terminal so that the vehicle receives sufficient voltage when cranking the engine. Otherwise when you crank the engine, the voltage to the ECU will fall to a level which corrupts the normal startup of the ECU - end result is an error code and 4000 rpm rev limiter.
• The cable run from the alternator to the battery is now very long, and has a connection or joint at the old positive terminal (as above).  The voltage regulator for the alternator is integral to the alternator. Thus the output voltage is determined by the voltage at the alternator. If there is significant resistance in the cable to the battery, then the voltage at the battery will be too low to sufficiently charge the battery. In this case a connection resistance of only 0.01 ohms (which is about 1/20th of what your digital multimeter can read) will result in a half volt drop at the battery.