Looking for some help with my LS2 swap. Thought I was nearing the end - and maybe getting ready to check for oil pressure (no plugs) but had heat/smoke come from the rear passenger side head ground stap wire. Traced wires and checked posts most of the afternoon, I'm stumped.

Harness was modified by Speartech. I tied into his harness at C100 by the brake booster for ignition and constant power. Used the GTO battery cables - on the positive side I tied in the 1987 camaro fuseable link leads, on the negative side I connected one ground to the body near the factory fuel pump fuse, the other is bolted to the AC compressor bracket (Which is bolted to the block). On the starter, I tied in the 87 starter purple lead on the small "s" terminal. The GTO harness also had a lead on this terminal as well - I tried connected and un-connected with no difference. Retained grounds on the rear heads, there are several connected on both heads. The car also has a racetroinx harness for the fuel pump, but I pulled all fuses for the pump so I don't think that is my problem.

I should add that the ground strap getting hot happended within seconds of holding the cables on the battery - ignition switch was off with keys removed.

Appreciate any help you all can offer - thanks,
Daren

 

Ugh, If ground strap is gettinn that hot, means lots of current going through it. I'd disconnect as many relays, fuses, power connectors as I could and see if issue still persists, if not, I'd add till it started, although that high of a current drain should blow fuses, circuit breakers, fuseable links etc, disconnect starter hot lead and see what happens? double check all battery cables?
Jealous of your motor

 

Have you tried reaching speartech? I would think they could point you in the rift directions for diagnosis.

Are there any power feed wires from either the large post on the starter, or a power block if you relocated them, that do not have fuses or fusible links in them?

 

Umm getting the ground strap hot just by connecting the battery,you got a dead short somewhere with your main power leads.Also I would add a ground to the motor directly to each head and main ground or frame bolt of equal wire gauge. You may have pinched a main power lead since no fuses have blown as far as i know to direct your attention to a specific circuit. I would disconnect the main links for the car from the gto harness and starter to isolate if the harness has an issue or the car harness itself has an issue.Good luck.Post your findings.

 

Had fusible links is beacause you have a non fused circuit that is a dead short. Find what power leads are not fused and check those first.

 

Thanks all. Read all the replies this morning, and also called John at Speartech. John confirmed no problems with grounds (as did my multi meter) and a short on a large current drawing positive connection. Checked a couple things tonight, fuses and fuseable links are intact and undamaged. Also checked my neutral safety start wiring. Checked the starter connections to make sure I wasn't shorted to the body or block. While I was checking for continuity from the battery cabes, I also checked across the 3 starter solenoid lugs and was surprised to have continuity across each set with no key in the ignition. That doesn't seem right. More research required...

 

Have the starter tested at a local parts store

Also,
move the battery ground terminal from the AC bracket to the block somewhere. Less it has to travel through

 

While your battery is disconnected, you can pull the starter out and temporarily join the power leads to the positive cable. If no more smoke after re-connecting the battery, you've found the culprit.

 

Congrats on the LS2, too!
These are helpful for future reference.

 

Update. Removed the starter and had it tested, reacted a little slowly - but energized normally the second test - maybe from sitting for 3 years....bench multi meter test results made sense - until I installed it back on the car. Same continuity issue between the ignition switch lead and the positive battery connection. Tracked it back to the positive battery cable connected to the alternator. When the alternator positive wire is connected, the circuit apears to be shorted. Tested multiple times, and with all combinations of other alternator wires (2 wire connection, racetronix lead for fuel pump). The short turns on and off when I connect the positive battery lead. The gto was hit near the alternator - I have removed it and will have it tested tomorrow. Here's hoping....

 

The wire to the alternator stud is black? If so, what are the chances the power lead got mixed up with the ground wire of same guage, that goes from the battery to the chassis?

 

This is the smae thing I was thinking. IIRC there is a black ground wire that grounds to the block near the starter and a red wire that goes to the starter. Maybe you have them reversed.

 

Blacks are to ground, reds are routed to starter and alternator. Something appears to be shorted either in the alternator, or along the positive cable that runs to the alternator from what I can tell so far.

No luck with testing the alternator today, none of the local shops have the pigtail to test this gto alternator. I'm going to set it on the concrete floor and hook it directly to my battery with a fused wire between the battery and alternator on the positive side and see if I get an arc or blown fuse. These gto alternators don't grow on trees, talked to a db electrical today in TN, but can't get a rebuild until early next week. Prices locally are $299 and up.....crazy.

 

Update 2/25/2013

Well, the car wiring is more torn apart now than it has been since I started this adventure. I feel like I’ve taken 23 steps backwards this past week, I have the whole harness out of loom. I’m judging “success” by testing for no continuity across the S and positive batter lugs on the starter (with key removed/off).

Starter itself was removed, bench tested, and taken to a local parts store where it tested good. I dis-assembled all of the GTO original battery and grounding wiring from the looms and inspected each wire – all look good. I connected the engine side ground directly to the block with a star washer per Jon’s suggestion. I think my original problem came from the positive stud on the back of the alternator. There is evidence of carbon where a washer/connection allowed the positive stud to ground against the alternator case and into the block. I purchased an isolator for the base of the stud, and verified it properly isolated the stud to case. I am not able to test the alternator itself – no shops have the connections for this unique piece (?)

After hooking everything back up, I still had continuity at the starter : ( - and thus the reason for this long update.

I was able to eliminate the starter continuity if I removed the fusible link connection to the positive battery cable (2 orange wires combined into 1 ring terminal from the factory, oranges on battery side turn to reds after links and go into C100 A4 and G5, also spliced together in front of blower motor from the factory). After more investigation, I could also eliminate the continuity is I separated the C100 connection at the firewall – suggesting to me the problem is inside the car (vs engine side).

The way the factory wiring is with these 2 fusible links – the short circuit could be coming from either circuit since they are spliced together twice – on either side of the fusible links (Factory splice near blower motor, factory splice on the ring terminal that originally connected to the starter, now direct to battery).

C100 A4 (larger dia) comes into the car and splices to LID fuse, PWR ACC circuit, and 2 leads to ignition switch.

C100 G5 comes into the car and splices to fog lamp, the headlight switch, and ACC fuse.

I dis-connected the PWR ACC relay, Ignition switch leads (2), fog lamp connector by the pedals, and the headlight switch. No change in problem. I found the factory splice for the C100 G5 connector – S201 – and cut this wire from the splice temporarily. In my mind, this essentially separates G5 and A4 circuits inside of the car. When I do this – I am able to solve the starter continuity by pulling the LID fuse, or disconnecting C208 in the rear hatch area. If I temporarily connect the C100 G5 connector again with a lead (Which ties the C100 A4 and G5 lead together on the engine side of the firewall), I have to pull both the LID and ACC fuses to solve the starter continuity. Pulling the tail fuse did not result in any changes (In the fuse block, the ACC fuse is connected to the tail fuse).

At this point, it was late last night and I was frustrated. I think I have a short at the rear hatch motor, and somewhere in my ACC circuit. Finding a short in this ACC circuit is no short order – many connections. If I have to go there, I located a large factory splice near the middle of the instrument panel – and I would propose cutting the wires from the splice one at a time until the problem went away, but I have to be careful with circuits with so many switches and bulbs..

Thoughts?

 

I didnt read all of the posts but i have my bat ground going strait to the pass side of the block and then on the same location i have got a 12" ground cable going from there to the body. My starter wanted a GOOD ground lol

 

BUMP just to say I hate when the resolution is never posted.

Frustrating.

 

Yup. So many just disappear into the ether. With that kind of current he most likely had a short on one of the big devices. That pretty much narrows it down to the alternator or the starter circuit. He could have stepped through adding the battery connections to track it down.

 

Sorry for not posting the solution, this was almost 4 years ago, and like many of you, I moved past this problem and quickly onto the next. I was racing to get the car running for a friends local car show back then.

Anyway - I recall the problem like it was yesterday. The alternator was missing the isolation washer under the positive battery cable connection on the back, thus completing the circuit through the case of the alternator to the block. The path of least resistance was then the heavy ground cable from the passenger side head to the car body. It was obvious once I took a break from it, and even more so in retrospect.

 

That would be the bottom bolt - you can see the isolation:

 

Well dang! You must lurk here all the time. Thank you for closing this up. Glad you got your car running and getting to the "enjoying it" part!