Thread: How many grounds in the engine bay?

Link is dead, can you summarize?



I got the same problem, I went to WalMart and picked up new terminals, they are bronze I believe. I just need to hook them up now hehe.

Ground loops are common amongst floating grounds... but it really doesn't apply to our cars seeing as the chassis is grounded to the battery and the engine to that, much like always (with the battery in stock or trunk mount). The chassis is always the constant ground for our cars. Ground loops are what happen when you do not have the same grounds in something. It causes voltage irregularities and other very bad things, which is what we are trying to prevent, but sort of does not apply to what we are talking about here which is using many grounds to make sure that everything is grounded to the chassis.

To many gounds can be bad. But in our car, making sure everything is grounded to the same thing is good, so having like 8 ground wires looping around your engine to the chassis is good. Just make sure your battery ground is grounded to your chassis as well.

Good info there zer099

I totally agree with zer099. Multiple grounds is fine as long as the grounds are to the same source..
This is why grounding kits adds a few more grounding locations but also uses existing grounds too (more ground surface and larger grounding wires) ..

Its strange that you mention floating grounds.. hehe
I was discussing this grounding principal with Vadim earlier this summer.
This grounding technique is the driving factor when applying the "Side Marker Blinking" mod and can be used for many other electrical mods.

We also discussed how all of the engine sensors are grounded at the same source as the ECU: Intake Mani...

Thanks to you Scotty, now I know what they are and how to use them

Fixed the link on ground loops. It does apply here, and explains why grounding to the fewest spots possible is desired.

Yep...

Ben,
This is a great article but it really doesnt apply here.
In our Nissans (and also Infiniti's), our ground is really separated by circuit ground, meaning that each ground is supporting a group of components participating in the same electrical circuit (physically or thru wiring): ie: exterior light circuit, ECU & sensor circuit, AC circuit, Alternator/battery circuit, etc. This exists thruout the car in the engine bay, interior, trunk, etc. All components are grouped and powered/grounded by a supporting circuit. This avoids the problem of grounding loops and allows for different volt/amp ranges between circuits. Within the same circuit, some floating grounds are also used and are fine as they share the same limitations.

This is why grounding kits are so effective with our cars. It improves the grounding for several major engine compartment circuits: AC, alternator, Battery, and Intake Mani (ECU/MAF/other engine sensors). But you can do the same thing inside the car for audio equipment, hvac, dash lights, power windows/seats/seat heaters, and many other circuits by increasing the ground quality with larger wires. Most high power Amps require this for power & grounding.

Most people get into trouble when they wire across circuits and cause the grounding loops. Some of the time, this will trigger a blown circuit fuse located beside the battery but only a select group of circuits are protected this way.. The resulting problems of this can be a royal PITA to identify and fix. Especially on the power side of things, as most people and shops dont use diodes & relays to isolate power.

BTW, it was this type of thinking that caused me suspect the O2 sensor grounding in B13's with Stainless steel headers. Although the O2 sensor is part of the ECU circuit ground (as one of the input sensors), its grounding is actually on the Stainless exhaust which does not have good grounding surface properties (possible grounding loop due to difference between Intake Mani & exhaust grounding properties). This was corrected for Infiniti models with OEM Stainless exhaust systems by using 4 wire o2 sensors and grounding the sensor to the intake mani with the other sensors within the circuit. Thus, we see improvements by also using the 4-wire O2 sensors on the B13/B14 with stainless headers and grounding it to the Intake mani where it belongs. The same can be said for the MAF mod... as the floating ground gets weak over time and a direct ground to the circuit ground (intake mani) corrects the problem...

One day, I need to finally do the O2 mod writeup....

Scotty I think I'll beat ya to that write up

You dont have all of the information Vadim.. I need to write it as some additional Calum ECU specific info is required. Also, testing info needs to be accurate..

I will do it... but thanks for your offer!