Negative Battery Cable Connection to block
Thread Starter
Burning Brakes
Joined: Nov 2013
Posts: 1,036
Likes: 119
Negative Battery Cable Connection to block
This is embarrassing, but I started a crank sensor job over the weekend, took out the headers, moved a bunch of wiring out of the way, etc. Came back to button it up tonight, and I don't have any memory of doing it, but I guess I unbolted the main negative battery cable from the frame/block, and I can't for the life of me figure out where it's supposed to go. I don't even have an extra bolt laying around that I'd need to secure it. Apparently it's so obvious, no one on the internet has ever bothered to draw a diagram or take a picture. It looks like it wants to go to the starter, but I'm pretty sure the starter gets its negative connection through the block. Pictures seem to confirm this.
Racer
Joined: Oct 2021
Posts: 389
Likes: 76
From: Chicago
This is embarrassing, but I started a crank sensor job over the weekend, took out the headers, moved a bunch of wiring out of the way, etc. Came back to button it up tonight, and I don't have any memory of doing it, but I guess I unbolted the main negative battery cable from the frame/block, and I can't for the life of me figure out where it's supposed to go. I don't even have an extra bolt laying around that I'd need to secure it. Apparently it's so obvious, no one on the internet has ever bothered to draw a diagram or take a picture. It looks like it wants to go to the starter, but I'm pretty sure the starter gets its negative connection through the block. Pictures seem to confirm this.
Thread Starter
Burning Brakes
Joined: Nov 2013
Posts: 1,036
Likes: 119
Administrator
Joined: Mar 2001
Posts: 367,676
Likes: 24,665
From: In a parallel universe. Currently own 2014 Stingray Coupe.
C7 of the Year - Modified Finalist 2021
MO Events Coordinator
St. Jude Co-Organizer
St. Jude Donor '03 thru '25
NCM Sinkhole Donor
CI 5, 8 & 11 Veteran
Moved to C5 Tech.
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,410
Likes: 3,964
From: Cape Coral, Florida
This is embarrassing, but I started a crank sensor job over the weekend, took out the headers, moved a bunch of wiring out of the way, etc. Came back to button it up tonight, and I don't have any memory of doing it, but I guess I unbolted the main negative battery cable from the frame/block, and I can't for the life of me figure out where it's supposed to go. I don't even have an extra bolt laying around that I'd need to secure it. Apparently it's so obvious, no one on the internet has ever bothered to draw a diagram or take a picture. It looks like it wants to go to the starter, but I'm pretty sure the starter gets its negative connection through the block. Pictures seem to confirm this.
It is above the starter.
Last edited by C5 Diag; May 4, 2023 at 07:57 AM.
Thread Starter
Burning Brakes
Joined: Nov 2013
Posts: 1,036
Likes: 119
Thanks. I don't think my block has this I just looked it over, and stuck my phone camera down to record the area for good measure. Are truck engines different? I know that small grounding wire that is with the big one is on the head on mine. I'm assuming I can just put the big one up there with it?
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,410
Likes: 3,964
From: Cape Coral, Florida
Thanks. I don't think my block has this I just looked it over, and stuck my phone camera down to record the area for good measure. Are truck engines different? I know that small grounding wire that is with the big one is on the head on mine. I'm assuming I can just put the big one up there with it?
Last edited by C5 Diag; May 4, 2023 at 09:17 AM.
Thread Starter
Burning Brakes
Joined: Nov 2013
Posts: 1,036
Likes: 119
I had RPMs occasionally drop to zero and the car die while driving, then it would come back. It did the same thing years ago when the headers where melting the wiring to the sensor. I just felt around some more, and I did feel something tucked almost between the starter solenoid and the block that could be a mounting point. Didn't feel as angular or as large as what's in the picture though, and I don't think I can get a wrench on it without removing the starter again. Should I be able to see this mounting point from the top of the engine?
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
2027 Corvette vs The World: Every C8 vs Its Closest Competitor
Joe Kucinski
10 Most Common Corvette Problems of the Last 20 Years!
Joe Kucinski
5 MOST and 5 LEAST Popular Corvette Model Years in History!
Joe Kucinski
2027 Corvette Buyer's Guide: Everything You Need to Know!
Joe Kucinski
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,410
Likes: 3,964
From: Cape Coral, Florida
With the RPM dropping like that and car shutting down certainly sounds like a crank sensor…so did you actually change your crank sensor ??….trying to read your post and figure out what’s been done…so now the car doesn’t start ??…we just need all the info.
Thread Starter
Burning Brakes
Joined: Nov 2013
Posts: 1,036
Likes: 119
I changed the sensor, now I'm reassembling. Thing is, this project was done over several days, and I guess I've forgotten I disconnected this cable, and I'm having trouble finding where it goes on the block.
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,410
Likes: 3,964
From: Cape Coral, Florida
Thread Starter
Burning Brakes
Joined: Nov 2013
Posts: 1,036
Likes: 119
I'm unconvinced I disconnected it at all. There was some real hillbilly stuff done with the wiring on this car. I wouldn't be surprised if it was just jammed in contact with the block somewhere, and I dislodged it when I moved the wires to get the headers out. I always take all my bolts from a project and keep them organized for reassembly, and I don't have any missing. Think I'd be OK just bolting it to the head with the other ground?
Thread Starter
Burning Brakes
Joined: Nov 2013
Posts: 1,036
Likes: 119
Well it's back together and running, I put the cable to the head with the other ground. It's running a bit rough, and with some mean backfires. I was hoping I'd be one of the people who could get away without doing a crank sensor relearn, but guess I'll need to procure a Tech II or clone.
Thread Starter
Burning Brakes
Joined: Nov 2013
Posts: 1,036
Likes: 119
Got a fancy scanner that can do crank relearning, ran it twice, and the car is still running like absolute crap. I suspect something is off with the wiring. Either it hates where I put the main ground on the head, or the solder joint on the new crank sensor harness that I thought was iffy but passable was not, in fact, passable.
Thread Starter
Burning Brakes
Joined: Nov 2013
Posts: 1,036
Likes: 119
I was able to find these photos of a 5.3 truck block. It look like there IS a different situation going on above the starter where the LS1 would normally have a main ground connection. I couldn't see that round projection, but that's definitely what it felt like when I was groping around. I guess I'll tear back into it for a third time this weekend to investigate. I can't reach or do anything with the dang headers in the way.
Race Director
Joined: Oct 2004
Posts: 12,859
Likes: 4,656
I hear ya about headers being in the way! I also know these LS PCMs dont like any grounds but the very best!! The cable is mounted on the block for a reason. I see a couple bosses with holes, just in front of the starter, one higher vertically than the other. Are they tapped/threaded? If this is a cast iron block, and they're not threaded, you'll need no cutting oil when tapping the cast iron-The graphite content in the iron acts as a great lube. Best of luck.....
Thread Starter
Burning Brakes
Joined: Nov 2013
Posts: 1,036
Likes: 119
I hear ya about headers being in the way! I also know these LS PCMs dont like any grounds but the very best!! The cable is mounted on the block for a reason. I see a couple bosses with holes, just in front of the starter, one higher vertically than the other. Are they tapped/threaded? If this is a cast iron block, and they're not threaded, you'll need no cutting oil when tapping the cast iron-The graphite content in the iron acts as a great lube. Best of luck.....
Race Director
Joined: Oct 2004
Posts: 12,859
Likes: 4,656
Bottom line is the negative cable originally bolted to the block. Truck blocks aren't so much different than LS1/LS6 blocks. The cable should be mounted where GM mounted it; on the block.. clean off any surface rust, get a short bolt, a proper sized eyelet, and bolt it to the block.....
Thread Starter
Burning Brakes
Joined: Nov 2013
Posts: 1,036
Likes: 119
Bottom line is the negative cable originally bolted to the block. Truck blocks aren't so much different than LS1/LS6 blocks. The cable should be mounted where GM mounted it; on the block.. clean off any surface rust, get a short bolt, a proper sized eyelet, and bolt it to the block.....
Race Director
Joined: Oct 2004
Posts: 12,859
Likes: 4,656
Last edited by grinder11; May 14, 2023 at 02:22 PM.