Proper Grounding for starter circuit

[Bundy]

I think I'm having grounding issues in my starter circuit.

How many grounds do I need? Where should these grounds run? Does the starter ground through the engine's ground?

Engine to battery?
Engine to body?
Body to frame?

 

[70_Steve]

The biggest current draw is your starter. So, a good grounding scheme would have the negative battery cable bolted to the engine block. Then pick up your body and frame ground from there. I've found a convenient place to attach the body ground is at the rear of the intake manifold, where there usually seems to be a couple unused bolt holes, and attach that to the firewall. I ran a ground strap from the negative battery cable attaching point to the frame.

 

[Bundy]

Okay cool. I have a good ground cable running from the 4G ALT mount to the battery terminal and then another ground off that post to the frame, and then from the frame to the body. Is that sufficient?

I ask because when I try and crank all i get it buzzing, no clicking or cranking. I'm thinking if my ground are good maybe my battery is toast. The odd thing is that it shows 12.5V when I check it but maybe it's just when there is a big draw?

 

[Broncobowsher]

That probably is a bad battery. Try reading the voltage again with a load on it, even the headlights being a good start. Of course the connections and the condition of the cables as well. Check battery voltage directly on the posts, not the clamps on the posts for best results.

 

[Bundy]

it was the battery... damned optima yellow top. I feel stupid because I have an extra battery and I checked EVERYTHING else before trying a different battery! Sometimes I forget to try the easiest fix!

 

[dave67fd]

Okay cool. I have a good ground cable running from the 4G ALT mount to the battery terminal and then another ground off that post to the frame, and then from the frame to the body. Is that sufficient?

I ask because when I try and crank all i get it buzzing, no clicking or cranking. I'm thinking if my ground are good maybe my battery is toast. The odd thing is that it shows 12.5V when I check it but maybe it's just when there is a big draw?

Although you've determined the battery is the culprit, you didn't mention a ground from the battery to the block just to the Alt. bracket.

To avoid any future problems you should connect direct from the neg. post to the Block as shown in the below pic (best to use black other than red as shown). Take your frame and body grounds from here or elsewhere on the block as mentioned. Make sure the connections are grease free and tight.

 

[Steve83]

The closer to the starter you ground the block, the better cranking performance you'll have. A starter bolt is best. Use a continuous cable from the battery (-) post to the ring terminal on the block/starter, but feel free to peel the insulation in the middle & solder (don't cut/crimp) on another ring for a frame grounding bolt. An even-easier way to do it is just snag the black battery cable from an '80-96 truck. They're common & cheap in JYs.

.

 

[Bundy]

So I changed my battery ground to go to the starter bolt and I still have the same issue- could a bad starter pull too much power? I am really at a loss here as my TBI setup won't fire because it isn't getting enough juice during cranking. At the ignition switch I watch it go from 12.5V at ON and then when cranking it goes to 1.5 and 3.8 and 6.2 and all over the effin place. Is that normal??

My cables and grounds are all new and good, I had the replacement battery tested and it passed (they did say it was in the last 1/4 of it's life). The only thing I can think of is the starter being wrong or bad.

 

[Broncobowsher]

Exactly where are you probing the voltage at? The battery post, the clamp on the battery post, at the starter, etc. This is VERY important. What you are looking for is a voltage drop. If the battery itself is dropping to those very low voltages, it's dead. At least a charge if not replace. But if those voltages are not at the battery, but at various terminals in the starter cables and the battery voltage doesn't drop that much at the battery than you are chasing bad connections. Check the voltage drop across each connection (under load) and when you get one that is excessive, that needs correcting.

 

[Bundy]

I've checked the voltage in a few places; the battery post, some unused switched 12V circuits in the harness, and at the post at the back of the ignition switch. They all show big drops, and it only happens when cranking. I've triple checked everything and all the connections are clean and have brand new cables. One from the battery negative to the starter mounting bolt, one from the back of the head to the frame and a strap from the frame to the body. I'm stumped.

 

[Broncobowsher]

Go get the battery tested

 

[xcntrk]

I would definitely suggest a dedicated ground strap for both the engine block and 4G alternator. Those explorer brackets are not sufficient to transfer ground between. I use those big fat braided grounding straps from Summit. Run my BATT NEG to a tapped grounding stud on my frame, and from there run x3 individual grounding straps to; Alt, Block, Body. Works great!

http://www.summitracing.com/search/part-type/ground-straps

 

[Bundy]

Thanks for the replies. My first yellow top was bad so then had a red top laying around that I put in and having the same issues. The red top tested good, 910 CCA but they noted that it was in the last 'quarter' of it's life span. I feel like my grounds are solid now, all new cables, freshly tapped hole to the frame and the starter ground going from the battery to the starter mounting bolt.

I'd hate to buy a new battery and have the same issue but it's gotta be the battery or the starter itself.

 

[ntsqd]

Time to step up & get a high torque starter?

 

[bronconut73]

If you haven't switched to the PMGR starter yet, now would be a great time.
Mine, from Autozone, has cranked on as little as 9 volts.
Awesome.

 

[Bundy]

That's the dilemma- is it the starter or the battery that is giving my electrical system the shits?

 

[Pa PITT]

.... Bundy .. I didn't read all the extra post. But back when I ran my parts store... I had an old 1980 300 cid NP435 BRONCO .. actually still have it.
... But I always had a BATTERY on it that should crank a Diesel. It always had ground issues.
... So I went to one of the Starter bolts & added an Eyelet cable on both ends. I took all the Tag ends back to the Alternator bracket. I added about 4 eyelet cables grounding every thing back to the alt bracket.
... Mine sure did crank better after that.
..I even put 2 smaller ground strap from both sides of my hood back to the body. Then even my radio worked better.
.. Then those 2 ground straps from the head light to the body .. & THE LAST TIME IT WAS running one of the head lamps wasn't working it was yellow. I had one of the grandsons take the ground loose & put it back on. Worked great after that. I'll bet I took that ground loose 10 times while I was driving it daily. ...
... I get whipped when I say you can't have too many grounds .. But sorry I like grounds better than walking .

 

[Steve83]

At the ignition switch I watch it go from 12.5V at ON and then when cranking it goes to 1.5 and 3.8 and 6.2 and all over the effin place.

I've checked the voltage in a few places; the battery post... They all show big drops, and it only happens when cranking.

First you said "at the ig.sw."; then you said at "the battery post". Are you using 2 voltmeters simulataneously?

Clean the battery posts to shiny metal, and fix the meter probes to the POSTS; not to the clamps AROUND the posts. Set the meter where you can see it during cranking. If it drops below ~10.5VDC at any point, the starter is pulling more current than the battery can supply. That doesn't prove if it's a bad battery or a bad starter, but it's a definite symptom.

If voltage stays above 10.5 there, move the meter to the ig.sw. and retest. If it drops lower than the battery post reading even for a fraction of a second, you have poor connections somewhere.

...new cables. One from the battery negative to the starter mounting bolt, one from the back of the head to the frame and a strap from the frame to the body.

That's a poor configuration, though not necessarily bad enough to prevent the engine from running. A better arrangement is:
1) battery to starter
2) SAME BOLT on the starter to frame
3) battery to inner fender

 

[ntsqd]

FWIW I have experienced the resistance from one side of an engine to the other be enough resistance to start the vicious self-discharging cycle between two batteries wired in parallel. Changing the grounds to be on the same bolt fixed that problem.

So if not the same bolt, make them as close to each other as is possible.

 

[Bundy]

Steve,

Where else could I attach a ground on the starter aside from one of the mounting bolts? As far as the other ground, I can swap the one from the head to frame to the same starter bolt but I'm confused when you say "to the starter".

I've got the voltage reading with one multimeter from both the ignition switch, different circuits I want to use for the switched 12V to the atomic EFI, and from the battery post directly, all at different times. They all reflected a massive drop in voltage during cranking, like all the way down to 2-3V.