ECU Ground location with a FFIM

[SC61 MK3]

You can always take a multi meter and test for voltage using the positive terminal of the battery and test different grounding points and see if there is a difference in voltage (if the voltage lowers, choose a better location)

 

[arknotts]

You can always take a multi meter and test for voltage using the positive terminal of the battery and test different grounding points and see if there is a difference in voltage (if the voltage lowers, choose a better location)

True. Is that all I should be looking out for though?

The stock grounding point is so close to the block, which seems like a much better ground to me...and I wonder why Toyota didn't ground it there. But then again, maybe (as I said before) I'm thinking too hard about this and it really doesn't matter that much. In which case they just selected that point out of convenience (being close to the wiring harness).

 

[SC61 MK3]

as far as I know, if you test two grounding spots using the same source for power and the meter shows no difference than there is no difference

but I have limited electrical knowledge and its mostly from installing car audio stuff so someone correct me if I'm wrong.

 

[SideWinderGX]

I haven't asked for aanything but for you two to explain why i was wrong. If you explain to me that i made a mistake, most of the time i will thank you for correcting me, and add it to what i know. If you tell me i'm wrong and don't explain, don't expect me to take you seriously. If you can't even explain your logic to someone clearly enough for it to be useful, why even say anything in the first place?

Just because the original grounds are on the chassis does not mean the best ground is the chassis. I think we all know by now that manufacturer specs. are not always correct... Look at most old hondas. there are three ground wires. 12ga each. they're meant to support like 100hp for 15 years and thats it. You think people are doing 300hp swaps with the oem grounds? No.

My point is I'm NOT an electrician, and as i said, if there is no waste, then why does anything in the car need a ground? Whether the component needs to dispell electricity, or a lack there of, it still needs to get rid of something, or there would only be need for a supply wire. To complete a curcuit you need a ground, and a 20yr old chassis is not the most reliable one.

I'm poor.

Accepted.

Horsepower output has nothing to do with electrical grounds.

You need a ground to complete a circuit. All circuits go full circle. Think of water flowing through a turbine to generate electricity...the water can't just disappear, it still has to flow out of the system.

A 20 year old chassis is a reliable ground providing you spend two seconds sanding the surface of the bolt hole you will be using.

 

[jetjock]

^ This. I about fell off my chair when I read that HP/grounding thing.

JJ, I know you're the electrical guru around here. Any advice?

In this particular situation any ground will do. If you want the very "best" connect to the negative battery terminal, either directly or through one of its two main branches. That means either the block cable or the main chassis ground on the left fender. I tend to use the fender because I also ground the igniter there. It really doesn't matter though which is why Toyota grounded through two sets of manifold bolts.

 

[spikesnstuff0905]

The point isn't that you have to get bigger grounds as you increase horsepower, it's that after 20 years of corrosion, the oem grounds are not neccessarily the best.

 

[SideWinderGX]

Unbolt them, clean them, bolt them back up. Now they are the best.

If you're worried about the wires themselves, you can buy new wire and crimp new connectors on the ends, but most of the damn wires on the car split off into a few different looms...I've only been able to replace a few.

 

[IJ.]

"ground loops" :runaway:

 

[3p141592654]

Lmao. You guys are killin' me. Hey Jon, are you getting all this down?

I'm taking notes! :icon_bigg

 

[arknotts]

Thanks guys. I think I've got enough information now.

In this particular situation any ground will do. If you want the very "best" connect to the negative battery terminal, either directly or through one of its two main branches. That means either the block cable or the main chassis ground on the left fender. I tend to use the fender because I also ground the igniter there. It really doesn't matter though which is why Toyota grounded through two sets of manifold bolts.

Thanks JJ. I guess in this situation I was being a little "paranoid" about where to ground it. It's good to know it need not be as precise as I originally thought. I think I'm just going to ground it to the block or the frame rail. I have a battery relocation which is grounded to the frame rail (yes I know there are plenty here who think it is best to run a separate ground wire to the front too...), so I assume this will provide adequate ground connection.

"ground loops" :runaway:

LOL. Is that not something that I should worry about too much in automotive electrical systems Ian?

 

[northsupra]

Haha this thread delivers! :yelrotflm

The hp statement really killed me.
Thank to JJ for delivering the facts as usual!