73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Electrical => Topic started by: velojym on February 02, 2012, 04:57:00 pm
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Well, I'm a friggin' idiot.
When I rolled Earl back a bit, a couple days ago, for a wash, I forgot to turn the ignition switch to the 'off' position.
So, today when I went to drive him to the post orifice, he was deader'n a doornail.
I backed my car up to jump him off, and after hooking up the truck's battery, one of the donor-end clamps fell and sparked against the truck's bumper. I saw no immediate ill effects, to I wiped my brow and hooked 'em up.
Once they were connected, I went back to start Earl, and noticed a prodigious amount of smoke coming from the block on the firewall, so I immediately disconnected the cables, grabbed my extinguisher, and kept a wary eye on the offending area. The wires cooled off and stopped smoking, so I parked the car and just leaned on Earl for a bit. I have to dig his manual out from the boxes in the basement, but I figure I'd go ahead and post to see if anyone can tell me how badly I might have damaged my truck.
There's no power at all to the ignition, the interior lights, or anything. Haven't checked the headlights yet... so I figure the least I'll get away with is a wire and maybe a big fuse.
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Went back out, though it's getting dark now. There's nothing electrical coming on. I checked a couple of the fuses, and they're still intact, and just out of curiosity I checked the battery on my multimeter. It's showing 8.65v right now, which is understandable since it didn't get a complete charge out of the above.
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Probably smoked a fuseable link on the junction block or at the starter.
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Probably smoked a fuseable link on the junction block or at the starter.
^^What he said^^
Quickest way to check is to test voltage or continuity from your battery to the alt; If its dead work you way to the dist block, then the starter.
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Probably smoked a fuseable link on the junction block or at the starter.
^^What he said^^
Quickest way to check is to test voltage or continuity from your battery to the alt; If its dead work you way to the dist block, then the starter.
Thanks. I'll try that in the morning.
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Probably smoked a fuseable link on the junction block or at the starter.
^^What he said^^
Quickest way to check is to test voltage or continuity from your battery to the alt; If its dead work you way to the dist block, then the starter.
x3. Sure sounds like the problem to me.
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I metered around, and found full voltage (left the battery on a trickle charger overnight) all the way back to the firewall. Between the little two-studded junction block and the fusebox was a wire with a spliced-in section of green insulated wire, just twisted together and covered in electrical tape.
Both pieces of tape burned away, leaving a couple of very iffy twist joints. I'm heading out to grab some lunch and see if I can find a bit of wire to more securely splice in. My fingers are crossed, hoping that someone's piss-poor wiring skills (it wasn't a fusible link, by the way) saved my truck from further damage.
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Nothing blew or even really melted. The previous owner's wiring left a lot to be desired, though. I wish I didn't have to keep putting off so much work on Earl, but finances aren't really there right now. I did go and get a proper fusible link, though.
Now it's crankin' some but the battery doesn't have enough juice in it just yet. Gonna leave it on the trickle charger for a few more hours.
This is just a little bitty charger I got for my wife's scooter, so I'm gonna have to spring for a real one soon. My old one went in a yard sale (unbeknownst to me)... hope the battery's still ok.
Before...
(http://a4.sphotos.ak.fbcdn.net/hphotos-ak-ash4/418492_10150563423660502_545785501_8796023_1682295721_n.jpg)
(http://a3.sphotos.ak.fbcdn.net/hphotos-ak-snc7/425354_10150563104720502_545785501_8795430_1926056000_n.jpg)
After...
(http://a1.sphotos.ak.fbcdn.net/hphotos-ak-ash4/418863_10150563460340502_545785501_8796098_1204991761_n.jpg)
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God that truck of yours is in nice shape!
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God that truck of yours is in nice shape!
Was that tongue-in-cheek? I'm not much good at getting jokes.
If not, yeah... this is a rust free, straight truck, with only a few problems due to a sloppy engine install. Otherwise, it's a great base for just about anything I care to do with it... still wondering about that, though.
Come to think of it... if they use a lot of salt up in your locale... yeah, Earl's in pretty darned nice shape. :)
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i was complimenting u! ;D "Earl" seems like he has been fairly well maintained exspecialy compated to 99.9% of trucks up in my area! I could only dream of fining one in my area for less than an arm and leg! ;D
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I'll have to remember that if I ever decide to sell him.
After we got home from dinner, I went out and turned the key. He started right up.
However, the voltmeter is a little lower than usual... just over the caution zone... the range with the white bar. I revved the engine a bit, and it showed no change. It dipped a little, then recovered, when I turned on the headlights, and revving the engine a little didn't do anything to the brightness.
I shut him off, waited a few seconds, and hit it again. He started right up... though if it's not charging, there's probably still a few starts left in the battery.
Could I have fried something in the alternator? Or did I just not really notice the "normal" range before?
Tomorrow I'll throw the meter back on and see if I'm getting good charging voltage independent of the gauge.
Edit: I went ahead and checked it. The truck started fine, but I was getting zilch on the multimeter, reading directly from the battery. That was odd... I shut the hood, turned on the headlights, and pulled out onto our street. The headlights started dimming immediately, and by the time I was a quarter mile down, I had no lights. I high-tailed it back to the house and parked him. A turn of the key and nothing. Dead again.
It had been running fine, even after the headlights were just about completely out, and the voltage gauge had bottomed. It didn't seem to want to die or anything until I turned the ignition off. Then, nothing.
Battery, or alternator? I'm thinking the battery is toast. No idea about the alternator.
Good thing they're relatively cheap in these trucks. Even so, I'll have to wait to afford one.
-just tested my multimeter. Works perfectly. Earl's gone nuts.
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Poking around this and a couple other websites, it appears that my alternator was probably keeping the engine running while it turned, and everything else died with the battery.
I left it charging overnight with a smart-charger, then through most of today. I got it to the point where it was reading full voltage, and started Earl right snappy-quick... about three times.
Then, with the headlights on and a quick drive down the road, it faded within seconds to nothing. Now I can't even get a tiny interior light to glow.
So, if I'm guessing right, and the Haynes manual isn't any help beyond this guess... my battery is toast, but my alternator should still be working ok.
Too bad the only spare battery I have right now is the deep cycle for our trolling motor.
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With the truck running test your battery...Should be about 13.8 volts if your alt is working.
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idk if you have a tester, but hook one up to the terminal on the back of the alternator when it is runing and see if it has any output. we had an issue simillar to yours where the alternator was good still, but it wouldnt charge the baterry and truck would just run off of the batery, found out that the fusable link by the starter was toast. i would test alternator and then check the fusible link next.
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No equipment beyond a multimeter here. Got no reading at all from the battery while the truck was running.
I didn't check the alternator. I'm kinda in the boonies, too. When I get started on the restoration, I'll be dead set
On having a backup system.
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Do the same test again, except this time go from a ground to the power wire off of your alt. If you have 13.8 ish here; your problem is between your alt and dist block or dist block and starter or you battery cable. Also clean up all the connections and tighten them all if you don't see anything obvious.
If you dont have voltage at the power wire on the alt replace the alt.
if you can't pinpoint the problem you can (carefully) use a jumper wire to jump the sections mentioned above; when you have voltage at the battery you have found the section that is bad.
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Agreed, sounds like the alt is working but the current isn't getting to the battery. Check all of those connections.
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Should the battery have died that quickly, though? It'll take a while for my tiny little charger to top it off again, so I'm having to chew things over mentally as I wait.
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I would say your alternator and now your battery is toast.
Like 1980 said you have to check with the truck running, but you should get 13.8 - 14 volts or so when it is running on the battery leads if the alternator is working properly, if it is lower, say 12 volts and your battery started out with 11 volts your alternator is putting volts out but not enough.
Batteries can only be run completely dry a couple of times before they are no good. Running them to nothing messes with the + and - charges on the plates inside the battery, it will destabilize the opposite polls on the plates and they will start to mix with each other and then the chemical reaction no longer takes place.
One more thing I would like to say. The wiring you found, the twisted together green wire with no kind of solder or fittings, I would start looking around for more just to see if that was the PO way of fixing things. :-\
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As suggested, measure the voltage at the alternator B+ terminal -It looks like someone made a botched repair judging by the pics you posted. Check the fusible link to the alternator and at the starter solenoid as well.
http://forum.73-87chevytrucks.com/smforum/index.php/topic,11972.0.html
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The truck's been sitting in a bog overnight, so I had to wait until the ground started to dry. When I opened the door, the interior light came on, so I tried the ignition. The battery seems to have recovered enough, overnight, to give the engine a little bump. My neighbor is bringing his battery tester over right now, just thought I'd toss this into the mix.
edit: The battery tested "bad". I put the charger back on so I can test the alternator later, but as for the wiring near the starter, it'll take me a while to figure that out. While I do have some experience working on airplanes, and am comfortable with normal maintenance on these trucks, I have very little practical experience working on wheeled vehicles... so please be patient if I seem like a complete clown.
-Got back, and managed to barely squeeze myself under the truck before the sky opened up. (Drop this thing? Ferget it!) I saw a couple wires that looked like fusible links near the starter, but nowhere I could get my ham-sized arthritic hands. When the weather dries up a bit again, I'll have another look. They looked fine from where I could see them, but I guess that doesn't really mean anything with links.
I'm starting to think it'd be a good idea to just get started on pulling the engine and cleaning up the engine bay. I'll have better access to all this stuff, and I need to replace a bunch of seals on the engine anyway.
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While I do have some experience working on airplanes, and am comfortable with normal maintenance on these trucks, I have very little practical experience working on wheeled vehicles... so please be patient if I seem like a complete clown.
I'm starting to think it'd be a good idea to just get started on pulling the engine and cleaning up the engine bay. I'll have better access to all this stuff, and I need to replace a bunch of seals on the engine anyway.
No worries, ask away. As far as removing the engine, if you are needed to replace seals anyway it would be a GREAT time to check wiring, like you said much easier to get to if you need engine out anyway.
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Like I figured, This will probably be the start of one of those domino-effect jobs. If I pull the engine, I wanna do the wiring right, so a new wiring harness would be in order. It's also a good time to get the surface rust off the inner fenderwells and do some general cleanup in the engine bay, replace the steering column...
Yep. Good thing I have a daily driver handy.
If I can get him to run in the meantime... until I have everything ready to go, I'd like to try to get this fixed. I saw what appeared to be two fusible links near the starter. I can't think of any reason why I couldn't replace both with fresh wire, and adding fusible links in a more accessible location, right? If the wires run to the alternator, is there any reason I can't install a new link on the alternator end instead?
I went out to start the truck this morning, and had a facepalm moment. When I rolled the truck onto the concrete pad, I again left the ignition switch on, and the tiny charger couldn't keep up... so I'll have to wait some more to test the alternator.
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Uhm... if I'm not missing something, couldn't I run a bit of 10ga wire (with a fusible link or fuse) directly from the alternator to the battery?
With this hack job, I'm wondering if this might be safer anyway.
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No, Do it right the first time. The purpose of the fusible link is to protect the circuitry from the feed source. Follow the wiring diagram & use the proper gauge fusible links.
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No, Do it right the first time. The purpose of the fusible link is to protect the circuitry from the feed source. Follow the wiring diagram & use the proper gauge fusible links.
Part of the problem is that the wiring diagram in my Haynes manual isn't really like the mess under the hood. I have to wait a bit anyway, though, as I know I need a new battery and have to worry about scraping up funds for it. Pulling the exhaust manifold to get to that fusible link is gonna be a pain, though.
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Why would you pull the exhaust manifold? That's unecessary. What's the year make model engine?
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Why would you pull the exhaust manifold? That's unecessary. What's the year make model engine?
Truck's an '86, came with a 305 but at some point someone dropped in a 350. It pulls pretty well, but the wiring was... well, you saw the pics.
My hand just won't reach the wiring attached to the starter, from above or below. I can see where I'd be able to get to it by removing the exhaust manifold on that side, or possibly the starter. I noticed on another truck that the wire from the alternator went directly to the battery, and looking at the wiring diagram, that's effectively what happens anyway, just via the starter. I don't want to do anything stupid, though... another hackjob isn't acceptable to me.
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I just did my fusible links, or should I say put some in where they were supposed to be. You can reach down and take the large and small nuts off the starter solenoid without removing anything. If you don't have long arms like me you might crawl underneath and do it. If you really want to get the wires up close to you then you can take the connections loose from the alternator, but its not necessary.
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I just did my fusible links, or should I say put some in where they were supposed to be. You can reach down and take the large and small nuts off the starter solenoid without removing anything. If you don't have long arms like me you might crawl underneath and do it. If you really want to get the wires up close to you then you can take the connections loose from the alternator, but its not necessary.
My wife jokes about my long arms, but my problem here seems to be my rather large hands. I'll have another look tomorrow, see if I can find another way in.
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Diagram and gauge
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Ok. I know there's power to the junction block, so the three things I'm worried about are the known bad battery, the fusible link from the alternator to the starter, and possibly the alternator itself.
One question, though... if the HEI requires power to run the engine, and if that wire from the alternator is bad... as well as the battery, what's running the ignition?
Our airplane magnetos can be a bit persnickety at times, but they'll go on running with no help from the battery or charging system.
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If you drop the starter you should have enough slack in the wires to lower it down and have good access to the connections. I would definitely track down the current problem before you pull the engine. You'll want to have a clean slate before you open up another can of worms.
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I agree, and I'm hoping most of the hack-job can be corrected when I pull the engine. I still want the truck running up until that time, though.
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I may have missed it but just some questions. Did you check the battery with it fully charged? Also a "good" battery can't run a truck for long especial with the headlights on. A good alternator will keep the truck running till you shut it off. Did you test the output post on the alternator to see what its putting out when the truck is running? Or what its at when the truck key is on. If I miss something im sorry but I don't think I saw this.
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I'll have to get him while he's home to borrow the tester again, but after a day or so of charging, I got it turning over snappy again. Then, after I got home this evening, I bumped the key just a bit, and it sounded like it had plenty of oomph.
I think my multimeter has a problem, possibly a break in one of the leads, so it's been less than useful through this. There's a cheap little one somewhere in the basement, and I'll see if I can find it to work on Earl, and to test the big meter's leads.
The voltage gauge on the instrument panel was reading about 12v the whole time, before, during, and after I ran the engine. It read the same later when I bumped the key.
Since I didn't have a working meter, I used a screwdriver to ensure that I at least had a field, and it did.
I just finished putting together a fusible link, leaving the 10ga side long so I don't have to make two of 'em. I'll run it directly from the alternator to the battery. If that does the trick, I'll know to go ahead and replace the wire to the starter. Everything I see says this will work just fine, unless there's something I'm overlooking.
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When your truck is running you should have about 13.8 volts. If your voltake does not increase after the truck is running you have an alt problem or possibly a wiring issue.
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When your truck is running you should have about 13.8 volts. If your voltake does not increase after the truck is running you have an alt problem or possibly a wiring issue.
That's what I'm chasing right now... or when I can get a little time. I'm gonna wire the alternator to the battery to see if I get a charge that way. If that takes care of it, I'll re-route that wire to the starter and be done with it... at least until I'm able to pull the engine and fix 'er up right.
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So you are going to run a direct bypass around all of your circuit protection?
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That's what I've been trying to find out. As far as I can get from anyone, including the manual, is that there's a fusible link on the line running to the starter... then the main positive cable back to the battery.
The wire I put together last night has a fusible link in it, so it would seem to offer the same protection the truck would have had if it were properly wired.
I did mention before that the P.O. dropped the engine in and just twisted together a lot of the wires, no solder nor any sort of protection at all.
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Don't take this the wrong way; you are making this harder than it has to be. Just test voltage at the back of the alt and ground for 13.8 volts if you don't have it replace the alt. If you have 13.8 at there and not the battery then replace the wire from the alt to the starter with the fusible link installed inline.
No need to wait until you pull the engine. Also you don't need to pull the engine to make repairs to the wire harness. I removed my entire wire harness to make the changes I wanted and reinstalled it when I was done. Its easy to just unplug untie and unbolt and pull it out. There is no better way to inspect it and know where you are really at than to lay it out on your workbench.
If you really want to run a wire from the alt to the battery to see if it charges the battery per your gauge. Just hook up one half of a jumper cable and check the gauge.
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Don't take this the wrong way; you are making this harder than it has to be. Just test voltage at the back of the alt and ground for 13.8 volts if you don't have it replace the alt. If you have 13.8 at there and not the battery then replace the wire from the alt to the starter with the fusible link installed inline.
No need to wait until you pull the engine. Also you don't need to pull the engine to make repairs to the wire harness. I removed my entire wire harness to make the changes I wanted and reinstalled it when I was done. Its easy to just unplug untie and unbolt and pull it out. There is no better way to inspect it and know where you are really at than to lay it out on your workbench.
If you really want to run a wire from the alt to the battery to see if it charges the battery per your gauge. Just hook up one half of a jumper cable and check the gauge.
Oh, I'm not waiting to pull the engine, just figuring a way around needing a meter, as mine is having issues right now. The engine pull will happen sooner or later, as funds and time allow. The install was just too sloppy, and there are too many leaks. At the very least, I want to go over the mill and replace all the seals, clean everything up, paint the valve covers, and go over all the bay wiring. I'm just looking for a patch-up solution that'll get me by until then, without torching poor Earl.
I do have a habit, sometimes, of overly complicating things... possibly a result of having way too many years behind the wheel, letting my mind run away with stuff. :)
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You can't own an old truck without a multimeter. Just go buy a $10 one. With a little probing and tracing you can figure out what is going on and fix it right. This will be easier to solve now before you pull the engine.
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Just hook up one half of a jumper cable one end to your pos on your battery and one end to the back of your alt and check the gauge to see if the voltage gauge in your truck moves up a little.
Doing this bypasses the fusible link and wire leading to your starter.
If the voltage increases replace the wire and fusible link.
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Just hook up one half of a jumper cable one end to your pos on your battery and one end to the back of your alt and check the gauge to see if the voltage gauge in your truck moves up a little.
Doing this bypasses the fusible link and wire leading to your starter.
If the voltage increases replace the wire and fusible link.
Yeah, that'd be a simpler way to do what I've been wringing myself out over.
and... yeah. I'd gotten used to having a decent multimeter handy, and it kinda threw me for a loop when mine started acting up. I'm gonna check the leads (if/when I get a minute to myself) and, hopefully, that's all that's wrong with it. I do have a cheap one packed up in the basement somewhere. I'll dig it out if I can.
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Kicking myself in the head for not thinking of it, but I'm going to need the wire I put together anyway. I used the jumper cable.
Pre-cable, I was reading battery voltage on the in-cab gauge.
With the engine running...
With the cable connected to the alternator and the battery, I'm showing a nice bit over the 13 mark. I nearly got excited enough to get the truck up on jacks so I could get under and install my new wire, but my arthritic joints told me to wait a bit, as the weather's gonna warm up in the next few days.
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what did you do to fix the charging problem
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what did you do to fix the charging problem
Haven't fixed yet, just diagnosed. I bypassed the wire leading from the alternator to the starter with a jumper cable, and found the truck getting full charge voltage. Since the starter is getting juice from the main battery cable, I've made a replacement fusible link/wire to replace the one from the alt to the starter.
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Ack. Forgot to post. I ran the new wire, and drove Earl down the road a bit, and found that my voltage was changing with engine rpms, from battery voltage up to around 16v. I'm guessing there's a voltage regulator problem there, and also... the battery is bad. I topped it off with a charger, and it'll be flat within three days or so.
Not sure if the regulator in this truck is part of the alternator, whether I can replace it without having to replace the whole alternator.... my repair manual shows how to take the thing apart, so I'm guessing I can if I need to.
I'll pick up a new battery when I get this part figured out.
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Yes the regulator is inside the alt. Only special tool required to take apart the alternator and put it back together is a paperclip or something similar to hold the brushes in place while you put it back together.
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I guess the alternator's part number should get me the one for the regulator I need?
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Do what you like but I wouldn't risk changing the regulator. Just take the alternator to a parts store and have it tested. If it tests bad buy a new one. If it tests good go over all of your grounds and connections.
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check the cost of an altenator; you may find it cheap enough that you don't want to go through the trouble of installing the voltage regulator
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i would recoment just geting a new alternator. they are cheep and usually have a waranty on them and then u know that it is right.
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I'm going into town tomorrow for some stuff. I'll pull Earl's alternator and take it with me, get it tested, and I'll just replace it if bad. The ones in these trucks are as cheap as they come, and you're right. I'll be a lot more comfortable if I know the part's history.
Same will go with the battery.
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If possible get everything squared away at the same time; stress in a starting system tends to cause more problems. For example you need to repair wiring, replace your battery and alt. All of those parts did not fail on their own. With this in mind, when you do this work make sure your connections/cables are all clean tight and in good condition. That way everything stays healthy.
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If possible get everything squared away at the same time; stress in a starting system tends to cause more problems. For example you need to repair wiring, replace your battery and alt. All of those parts did not fail on their own. With this in mind, when you do this work make sure your connections/cables are all clean tight and in good condition. That way everything stays healthy.
Dominoes anybody ? :D
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If possible get everything squared away at the same time; stress in a starting system tends to cause more problems. For example you need to repair wiring, replace your battery and alt. All of those parts did not fail on their own. With this in mind, when you do this work make sure your connections/cables are all clean tight and in good condition. That way everything stays healthy.
Dominoes anybody ? :D
That's exactly what I was thinking. I started out just looking at the most obvious problem, the fusible link by the junction block... and after fixing that, I've chased it all the way back to the alternator and battery.
I'm not even going to crank this truck until I get all that squared away. The P.O. was a P.O.S. ...at least insofar as working on my truck was concerned.
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Who's name is Earl? The truck?
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Who's name is Earl? The truck?
Yep, Earl Grey
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Haha funny i like it. Gotta think of a name for my truck now. Something like... Beat up Sally.
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Finally got to replace the battery and alternator today. Now the voltage on the dash gauge isn't swinging with the rpms. It's inside the range above battery voltage, so it would seem to be charging, but I'm not entirely confident in an ancient stock dash gauge, so I'm gonna have to either fix my multimeter or find someone nearby with a proper tester.
Drove to the country club and back with no apparent issues, engine's running well, but now my driver side power window is completely inop, and with the temperatures we've been dealing with lately, those 10 minutes or so in my truck ended up with me being completely soaked in sweat. The only things I can imagine are: corrosion on a connection while the truck was sitting and/or critters took up residence somewhere in there, causing electrical problems. Given the weather, I'm going to have to move the windows up on my (ever so slow) list.
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Drat. Either I stripped the threads in the negative terminal of the battery, or it was already stripped when I bought it. Since I've changed hundreds of batteries in airplanes and a few dozen in ground vehicles, I don't think it felt like I cross threaded it myself, but that won't fly well at the parts shop.
So... I can get a slightly wider self tapping screw/bolt, or jam/melt a .50 cal lead ball (from mah muzzleloader) into the hole, and drill/thread it back to stock. I'm really kinda thinking the first option, at least for a while. I'm gonna have to gut the engine compartment at some point anyway, and when I do that, I'll be after a better battery anyway.
Drat again... when I was distracted by the boogered terminal, I forgot to re-attach the 12v, so Earl wasn't charging just now when I drove to the truck stop and back. I'll re-connect that tomorrow when it's light out. My brain has been mush lately. I'm in school for network engineering, so maybe my brain's just full, and I'll stick with that excuse for now.
Driving Earl again, though... even with the window up... was pretty awesome. I was really missing having a truck handy.
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Ahhh... charging again. Now Earl is back to being able to work near home, hauling the boat to the nearby lakes, mulch for the yard, etc. Still have a list of things to do, but it's nice to be able to drive my truck again.
In this heat, gotta get those windows fixed, still have to replace the cooling fan, and chase down an oil leak or three... among other things.