PDA

View Full Version : Vehicle grounding / electrical experts Please chime in...



obengston
11-13-2013, 04:31 PM
I have a 68 Camaro that I currently have many electronics to include the Fast 2.0 . I currently have the battery located in the Trunk. The Battery Positive going from a Lug at the front to the battery in the trunk. The Battery Ground goes straight to the frame, and from that spot on the frame I have a 1" grounding strap going to the body. Also on the driver side rear I have a 1" strap from the frame to the body. On the front I have a 1" strap on both driver /passenger side going from the frame to the body, also a ground cable going from the block to the frame.


Is there anything wrong with this?

mmosley
11-13-2013, 06:44 PM
As long as the connections are good should be no issue. May be a problem if trying to ground through powder coating or paint. Check continuity or resistance from one point to another. Resistance through grounds should be minimal.

obengston
11-13-2013, 07:42 PM
Reason I ask is I have ran it for over a year now (with a carb) with no issues, now I have the fast 2.0 and have a gremlin that I'm chasing and someone said my setup was not good and could possibly be the issue (which I really don't think it has anything to do with whats happening). Suggested that I need to run the ground from the battery to the engine block.

Motorcitydak
11-13-2013, 07:50 PM
Do you have a multi meter? If not, you should get one. They can be had cheap but get something mid range, like $50-100. Check the resistance from the - post and check every other area of the car that should be grounded. You can use a long wire to get from the trunk to the front. Also clean up all the connection areas. Just because 2 pieces of conductive metals are touching does not mean that they are going to transmit electricity properly

obengston
11-13-2013, 08:07 PM
Yes I have a meter. But exactly what am I looking for. Connect one end to the battery (pos/neg side??) and the other to the different areas on the fram/body that I'm grounding to? What kind of numbers will I be looking for (good/bad)

NOT A TA
11-14-2013, 07:09 AM
Electricity travels the path of least resistance. That path might not be the path you expect it to follow. AND that path might change due to increased resistance if the path of least resistance is a small wire or poor connection that warms up during use. I've seen fried transmission shift cables, body to battery ground wires, etc. when the direct engine to battery ground isn't good or has been changed to a setup that requires the starter current to seek an indirect way back to the battery when cranking over the engine.

We'd think the electricity should flow from the + battery cable to the lug in the engine compartment, to the starter cable, through the starter to the block, through the block, to the engine to subframe strap, through the body mounts, through the unibody, then through the ground strap in the rear attached to the -battery terminal. However if any of the connections after the starter aren't great the electricity will find the path of least resistance which might be through the block to transmission and then through the trans crossmember, an automatic shifter cable, or even a small ground wire from the body to subframe. If the path of least resistance heats up due to small diameter wire or marginal contact at each connecting point the resistance goes up and may force the electricty to reroute.

So while checking the car with a meter while cold can provide useful information it may not be an indication of resistance if any given circuit is active and possibly even getting hot.

I've seen so many problems over the years with indirect engine grounding I will not wire anyone's car without a direct engine to - battery cable. It reduces strain on the battery and reduces the possibility of problems.

Heleanor
12-02-2013, 04:40 AM
John, you nailed it! I must agree, when it comes to grounding a car take no chances. Negative cable from engine block to battery is the best scenario.

Mark.