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Discussion Starter #1
My Camaro hasn't been running for awhile during my engine upgrade. I kept the battery charged up and its holding a constant 12.8V. My battery is in the trunk and I tested the voltage at the starter and alternator and getting 12.8V there as well. I checked the master fuse and all fuses in the fuse box, all good. I checked all engine compartment grounds and they are good. I tested the system by taking one fuse out at a time with the same problem remaining. When the key is turned to run, the voltage gauge only shows 8V after doing a slight jump and when key is at start it goes to the lowest point. The horn isn't getting enough power, signals don't work, hazards draw all power away from the dome light and it blinks out but the hazard lights arent lighting, the headlights don't work at all, same with other higher power things such as the starter solenoid, radio, wipers. When the key is set to start, the dome light and horn correctly go off.

I triple checked all engine compartment wiring which is the only thing I disconnected during my engine upgrade. I don't know what to do now, anyone have any insight for me?
 

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Re: full power not getting to the fuse box

If your horn relay is still there, it's the power junction that feeds the main fuse panel. It's bolted to your radiator core support on the left side. You should see the 10 AWG power wires screwed to the bus bar on it. Sometimes corrosion will build up there. You can try cleaning it up, but a new one is less than $30 at AutoZone or similar parts store.
 

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Did you move the battery to the trunk during this upgrade? Or was the voltage fine before the engine swap? Did you add/reinstall a/the ground from the block to the frame? I am talking about a large gauge wire from the block to ground to "replace" the ground wire from the battery to the block. Having only the radio ground wires to the block is probably not enough. The whole car use to be grounded through the engine (basically)...

My guess...
 

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When you tested for and got 12.8 volts at the alternator, slowly work your way from there to the interior where the other gauge is getting power and at points you should find lower voltage readings (you may find out the other gauge reads differently than your meter which is going to happen some times).

It could be a connection on a wire (like on the terminal on the wires at a junction block/horn relay), a connector to another connector (like how power or signal is trnasfered from one side of the firewall bulkhead connector to the other side), and so on.

With a meter you should be able to trace it down.

One thing you may notice is let's say the ground of the body is poor to the relationship of the engine block and/or battery negative terminal. If there is a ground difference having the meter grounded on the block while doing tests under the hood and then switching the ground on the meter to a spot under the dash the meter could show lower voltages. What I've done before is make the negative wire on my meter long to allow it to be at one constant point and then do voltage checks using this as a constant and using the other test lead attached or probed into other spots to see what voltages I have and then change the ground over to another spot. If the ground of the car body is the same as the battery ground and the engine block then all voltage check points should be the same with just this ground moved. If not then something is not grounded well.

Most factory terminals are not soldered to the wires and while they may look good and be mechanically strong, the electrical flow could be diminished due to corrosion.

Thinking about this is might just be a poor connection at the battery. The meter does not draw much power at all but when other things get turned on like the ignition, headlights, and so on the voltage could go down due to a simple battery cable connection problem.

Jim
 

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Discussion Starter #5
Oh I should have elaborated on my setup a little more! I have a trunk mount battery since I rebuilt the car in 2005. I have a 18 circuit painful wiring system installed. I have two grounding braids to the engine, one on each side and attached to the firewall. My horn relay, turn signal is mounted to a blade type fuse block in teh factory position, the hazard relay is under the dash seperate from the fuse block. The battery is grounded to my trunk floor panel and the positive cable is 2 gauge, or 1 gauge I forget, anyways I've never had a problem with it until now.

Only the alternator, starter, distributor, elec. choke and engine ground wires were removed. I installed oil baffles, crankshaft studs, crank scraper, ported my manifold, changed the carb booster, installed cylinder heads and new exhaust manifolds and painted my brake booster / master.
 

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Jim has a ton of good ideas.

If you are only running those two braided grounds from your block to ground, I would consider a heavy gauge wire, as well. Lots of amps get drawn when trying to start a tight motor...

As far as the problems you are seeing, you may also want to check the connections (again?) at the starter... But many weird things happen w/ bad grounds. So, as you probe around, also check for proper connections - meaning positive lead/wire to positive posts, negative to negative, ign. to ign., etc. I imagine you are calling Painless "painful" for a reason? lol

Don't let it ruin your sleep! ;-)
 

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Discussion Starter #7
I found out another thing, one of my mini testers is going haywire! I used my other one and getting voltages that actually make sense, I'm actually getting 12.99V at the battery, 12.98V positive post to chassis. Up at the front of the car I'm getting a measly 8.6V from the + battery cable on the starter to chassis or engine ground and the same at the alternator to engine or chassis ground. The battery was connected all night so I know I'm not getting a short anywhere as the voltage is the same as yesterday but the interior light isn't even coming on now. Tomorrow I'm going to attempt to short the starter solenoid directly to the power post, it should be able to power the solenoid at least.
 

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Try getting your jumper cables, clean the frame a little, and clamp the front and rear frames together and see what you get up front.
 

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Did you take these measurements before the engine swap? Could just be "normal" losses due to "small" positive cable from trunk to starter... Oh and what do you have running from positive to the junction block?
 

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Discussion Starter #10
Try getting your jumper cables, clean the frame a little, and clamp the front and rear frames together and see what you get up front.
ok ill try that if my cables reach. I didn't actually remove the engine, just lifted it in place. That battery cable is big, about 7/16 diameter of wire. I don't really have a junction box, just a 50 amp fuse after the starter positive to both the alternator and fuse block...Going to try a few more suggestions.
 

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Discussion Starter #11
ok so my engine grounds are just fine and its not my other tester. When I tested the voltage at the front I am only losing 0.1V between the front and back. I went to start the car and nothing....THEN the voltage at the front dropped down to 1V and it slowly climbed up to 4V.

I disconnected the positive feed to the starter and the voltage testing only the battery cable went back up to 12.6V. Then I held the 10 gauge red power wire which connects to the same post on the starter to the battery cable, tested the voltage and it dropped down to 6V, again, the voltage is still slowly climbing back up regardless of power to the system or not, its like my main system is acting like some kind of capacitor. I disconnected the alternator (1 wire alt) cable and no change so its not the alternator causing this.
 

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Discussion Starter #12
Ok for ****s n giggles, I tested the voltage between the battery cable and the 10 gauge wire to the alternator and harness, getting a full 12.6V where it should be 0.0V...I still don't know how the entire car is acting like a capacitor but now I know I'm getting a full ground from the fuse block ~somewhere~
 

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Discussion Starter #13
So I pulled all the fuses, the turn signal relay, the horn relay and I'm still getting a full ground somewhere. The fuse block main power wire is only ziptied with the rest of the engine harness wires and it hasn't been altered at all, I inspected it and it has a clean run into the fuse block. How is it possible that this wire is getting grounded with all the fuses and relays out and the wire is in good shape? Also, howcome the battery isn't dying from this short?
 

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You said it only shorts when you turn the key on, right?
 

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ok so my engine grounds are just fine and its not my other tester. When I tested the voltage at the front I am only losing 0.1V between the front and back. I went to start the car and nothing....THEN the voltage at the front dropped down to 1V and it slowly climbed up to 4V.

I disconnected the positive feed to the starter and the voltage testing only the battery cable went back up to 12.6V. Then I held the 10 gauge red power wire which connects to the same post on the starter to the battery cable, tested the voltage and it dropped down to 6V, again, the voltage is still slowly climbing back up regardless of power to the system or not, its like my main system is acting like some kind of capacitor. I disconnected the alternator (1 wire alt) cable and no change so its not the alternator causing this.
I still think in the long run you should put a heavy gauge ground from your engine to the frame. Those two little grounds are fine for most stuff. But will probably get pretty hot when doing some heavy cranking to start the engine.. Also, they are fine for testing w/ a volt meter as very little current is being generated... I also wonder how the rest of your car is getting power?

The weird voltage readings seem to point to a bad power to ground loop. I don't know about the single wire alt. set ups. Since you diconnected your starter and ingition (coil, etc.), again, I would start there. If nothing else was changed or added, how could it not be somewhere there? Did you say you tried another (good) battery? Maybe this one is near it's end?

Ok for ****s n giggles, I tested the voltage between the battery cable and the 10 gauge wire to the alternator and harness, getting a full 12.6V where it should be 0.0V...I still don't know how the entire car is acting like a capacitor but now I know I'm getting a full ground from the fuse block ~somewhere~
It all matters how you have the power coming from the battery to the rest of your car. You are probaby measuring voltage across an open ignition switch at that point? Try measuring w/ the ignition in the run position. Wait, do the battery cable and 10g wire go to the same terminal on the starter?

Again, I really don't see how you are getting power to the rest of the car. I meant to say Junction Block, not box, if I said that. When the battery is in the engine compartment in it's tray, a wire (fusible link?) runs from the positive terminal of the battery to a little piece of plastic w/ a stud on it that is right behind the battery. From there, it is normally routed to the horn relay, voltage regulator (yours is now internal to the alt.), and alt. The power to the rest of the car continues on from there... I'm pretty sure the red wire on the starter solenoid just powers the solenoid.

OK, it's not so fun anymore... :p I don't understand how it was fine before removing a few wires and now it's not! Either it's wire put back on correctly, bad grounds or connections, or the battery?.?. :confused: I don't know, man. I feel like I'm guessing or making stuff up, now (second guessing myself)... Maybe I should stop "thinking out loud"... :sad:
 

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So I pulled all the fuses, the turn signal relay, the horn relay and I'm still getting a full ground somewhere. The fuse block main power wire is only ziptied with the rest of the engine harness wires and it hasn't been altered at all, I inspected it and it has a clean run into the fuse block. How is it possible that this wire is getting grounded with all the fuses and relays out and the wire is in good shape? Also, howcome the battery isn't dying from this short?
I don't think there is a fuse between the red wire on the starter and the ignition switch. If that's the wire you are talking about?

Turn signal relay?
 

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Ok for ****s n giggles, I tested the voltage between the battery cable and the 10 gauge wire to the alternator and harness, getting a full 12.6V where it should be 0.0V...I still don't know how the entire car is acting like a capacitor but now I know I'm getting a full ground from the fuse block ~somewhere~
When you put a meter inline then you could read 12 volts when something past this point (further down this 10 gauge lines circuit) is trying to come on. If you read 0 volts then nothing past and down the 10 gauge line is needing voltage to power up. If it was a short then the voltage would be going down and down since the battery is nothing more than a storage device.

To do a test and become more familiar with how things can work is grab an old taillight bulb and socket with some wires coming off of it. One wire should go to the filament of the bulb and the other should be to the ground base of the bulb. Take your meter now and see what the battery voltage is with nothing connected to it but the meter. Let's say it's 12 volts for a number. Now take the meter off of the battery and connect one wire off of this old taillight bulb and socket to the battery positive post and the other wire to the battery negative post and the light should light up as this is how it should be (if it doesn't the bulb may be bad or something else but with these two connections a good 12 volts bulb should light up). Now disconnect the one wire off of the battery positive post that is going to this test bulb and socket and put your meter inline with one test lead on the battery and the other to the wire going to the test bulb and socket wire. The meter should now read 12 volts or real close to this and this would be correct. Now with all of this still connected, take the bulb out of the socket and the voltage should go down to 0 volts.


I'm really thinking you have a connection problem (or maybe even a battery storage problem).

Think about this and see if my reasoning is right. Let's say you have a good battery that can hold a charge and output whatever we need. You then have a wire terminal end on the positive post of the battery that then connects to a large wire. This large wire then goes up front and ends with another terminal that is bolted to the starters main power lug. If you then tested with a meter right on the battery terminal posts the voltage would be, let's say 12 volts. You then take this same meter and now leave the one test probe attached to the negative battery terminal and then see what voltage you have at the front terminal up by the starter and you have 12 volts up there. Now you then take a screwdriver and short the starter to make it pull big power and the starter does not even engage so you then check the voltage at the starter and you see it at 6 volts and it is slowly climbing and maybe eventually gets back up to 12 volts. You say there must be some type of capacitor that is recharging but there is none. The reason for having this low voltage and then it slowly climbs is a single or multiple poor connections. Meters do not draw anything to measure voltage. A poor connection has resistance and when a meter is used from one point to another, voltages should stay up but now introduce a big current draw like a starter and this little poor connection becomes a restriction and this restriction creates heat. Heat and restrictions reduce voltage. When a poor connection cools, guess what, the voltage should come back up as the resistance across this poor connection is less.

I hope you followed that.

This being said, you can pull power off of the battery through terminals, wire, and connections but you have to remember this power also has to get back to the battery through it's terminals, wire, and connections. If you do not have this loop, then things will not work and you will have voltage drops.

I hope I haven't rambled on and made it more confusing for you.

Jim
 

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Discussion Starter #18
My battery and cable from the trunk are proven good. How the wiring starts on my car (and always worked) is the battery cable goes straight to the starter positive post. From there, the 10 gauge red wire transmits the power through a 50 amp fuse on my firewall, splits into two red wires, one goes to the alternator. A second red wire from the same post on the alternator reconnects with the exact same wire, this was engineered by painless to allow for a high amperage alternator. That single red wire then goes straight into the fuse block, which also contains a modern horn relay.

Anyways, I was on the right track with the fuse pulling except how I did it the first time was pull one fuse, look at the voltage (ground test), then I put it back in and went down the line. This time I pulled off all circuits that aren't necessary for driving or circuits I have not connected yet, like cig. lighter, dome light, power windows, electric fan, radio (x2), fuel pump and having ALL those out stopped the G.F. I reinstalled the starter wiring and alternator and NOW its running normally. I haven't found the exact cause of the fault yet but its not an essential circuit and I'll take my time to figure it out. I also remembered that I used to have an alarm system installed, all I left attached to the car harness was the connectors from it and the car didn't move at all during the upgrade and I didn't do a thing with it like that for years so that shouldn't be the problem but I'm removing all of that anyways.
 

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I'm glad you are making progress!

Me, I should have bowed out after hearing Painless wiring (upgrade kit?) and single wire alt... lol
 
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