The most important thing we can say about grounding is that you want metal to metal direct contact without paint, dirt, grease or debris. A clean ground is a good ground.
What is Grounding?
To make sure your car is running as efficiently as possibly we need to make sure our grounding system is working as smoothly as it can. The most common analogy for how DC (car battery) current works is to think of it flowing like water from positive to negative. With that in mind we can send all the power we want out from the positive side but if our connection to the negative side is weak, there is no flow. With this in mind, having a good alternator and battery pushing out a ton of power does nothing without good grounding.
When it comes to grounding issues, where do I start?
Grounding issues tend to be the root cause to a lot of random weird electrical problems. Bad grounds can cause a lot of symptoms you wouldn’t expect like the immobilizer not working, phantom misfires, ECU staying on all the time, etc. It’s difficult to predict what pathways ground issues are going to take. As mentioned earlier, electrical current flows in a similar way to water so it’s going to find the path of least resistance which might lead to it flowing where you do not want it. This can cause grounding issues to pop up all over the car even if the bad ground is in the engine bay.
If there are weird codes or check engine lights, we suggest checking out the source of the issue being described in the code first. If that looks good, then a way to eliminate another variable would be to add a grounding kit. Once you know that grounding is not an issue, you can then troubleshoot more.
When ground issues are commonly the problem:
- TGV deletes or TGV spacers. The ECU get’s its grounding from the top of the intake manifold. When you put a plastic spacer between the intake manifold and the block as well as using the provided plated bolts that don’t conduct well, you lose the grounding to the intake manifold.
- Painted manifolds, painted alternator bracket or painted engine bays. The paint takes away the metal to metal contact so the ground is lost.
Big 3 Mod and Grounding
The Big 3 Mod consists of an alternator power wire, grounding on the engine block, and grounding on the negative terminal on the chassis. Our grounding kit takes care of the last two but we do not include an alternator power cable. It is rare that the power side of a circuit is causing the problem for engine functionality (except if the battery is dead). An alternator on a standard Subaru has plenty of power to run any of the standard features so we’ve left it as is.
Installing the iWire Grounding Kit
Made with high quality materials the iWire Grounding Kit can be run through the engine bay any way you like. You can hide it away for a tucked look or just throw the grounding kit on top. You'll just mount the black junction block to your chassis and then use the ring terminals to bolt into the following locations:
1. Chassis where negative battery ground touches
2. On the engine block
3. On the alternator housing
4. Intake Manifold
- For Metal Manifolds - bolt to top
- For Plastic Manifolds - bolt to the TGV block
Here is a link to the full install video for the iWire Grounding Kit.