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73-87 Chevy _ GMC Trucks => 73-87 Chevy & GMC Trucks => Topic started by: nova801428 on November 18, 2007, 01:29:07 pm
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A long time ago (a year or so) I was having brake issues. I then replaced my master cylinder twice and I thought that would have fixed it but my brakes still sucked. I took it to a shop and the mechanic replaced the master cylinder because the re manufactured one was crap. Anyway, I know my alternator is crap, should I take it back and risk another one?
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You can measure the output of an alternator. Go ahead and get it, keep the receipt, ensure warranty. Then install and hook up the voltmeter.
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Failure analysis? What made it fail? was the rubber under the cap swollen? Was there contamination in the system?
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not all reman stuff is crap. you just got unlucky. and not to mention, not knocking you, but are you sure the brake stuff was installed correctly...?
as to the alternator...i've bought plenty and gotten most all good ones...i think you're safe...
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Yes, the master cylinder was installed right. For some reason the seals leaked or something like that...this is when my bro owned it. He for some reason knew the system way better than me. Anyway, I took it to Autozone and it checked out alright. I went off-roading last night knowing this was a problem. We jumped it, drove 5 miles, did some off-roading in deep water (to the bottom of the door) then we starting driving back. My windshield wipers would not work since there was no power, then I drove 1/2 way home, and I stopped because I would have got pulled over for really really dim head lights. We jumped it again (let it sit for like 3 minutes then went. I barely made it home. Then, the next day I went to Autozone and they checked the alternator and I took the battery and both checked out good. I just replaced my negative battery cable and tried to move my truck, but it just won't move (It just clicks, then I turned the head lights on, now it does not do anything) I can't remember what someone suggested me, but if Autozone's machines ACTUALLY work (I think the machine always tells it to pass no matter what....lol) then something is causing my battery to run dead. I have nothing on except my head lights. What do you think? What should I look and test for?
Thanks
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With the truck running and the alternator connections/batt connections good...check the voltage at the battery with a meter.
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Shouldn't it be like 12 or so? What happens if it isn't....then is the alternator shot? And if it is then something else is my problem, correct?
Thanks
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No, the battery should be about 12.7 or so sitting w/out motor on. The alternator should be pushing about 14 volts or more when running--at least if you check it at your battery.
If not, it could be cable connections (red wire at starter--or black grounded to block or alt bracket) or alternator wire connectors. Could be battery connections or it could be be the alternator itself.
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O.K, I jumped my truck with my other truck. My other truck read 14.7 at the battery running. As soon as I jumped my truck (chevy) then I took a reading and it only said 11.8. So, what's up? Do I have to completely charge the battery for this to work....because it shouldn't matter since the alternator should supply the correct amount of power all the time, right?
Thanks
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You have no charging system output. Either your field ckt is open or just replace the alternator.
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Field ckt? Please explain? Say I buy a new alternator....how do I prove that my alternator is shot to the dumb &$%! at Autozone? Thanks
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Tell the clerk at Autozone what you told us
O.K, I jumped my truck with my other truck. My other truck read 14.7 at the battery running. As soon as I jumped my truck (chevy) then I took a reading and it only said 11.8. So, what's up?
If you don't like his reply, return it and buy somewhere else. ;)
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well, before you go in there with "both barrels smoking", you might wanna make sure all your wiring relating to your alternator is good (ground straps, battery cables, alternator wiring)...one wire bad and you get no charge...doesn't matter if your alternator is putting out 14v or 140v.
and be sure your wires are good...don't just look at them, get a multimeter and check for continuity and make sure there's not anything wrong you can't see
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They just gave me a new one, after I was throwing mine around in the gravel....lol. Anyway, we'll see how it works
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Yes, I checked (visually) my wires. I replaced the - cable, and I am going to do the + tomorrow. If that doesn't work then....I don't know. I'll find it sooner or later. Luckily I just fixed my other truck today (wiring issue) so now I can drive and get parts.....yay!!!
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well, like i said, i'd get a multimeter and check them for continuity. it's not all that uncommon for a wire to have an internal break and that be enough to lose connection. and you won't see it with the naked eye. also, you might wanna check your fusible links. i wanna say one of them (don't know which one, will look for ya though) will cause you not to get a charge if it blows...
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Good luck finding the problem :(
I will be starting the rewireing of my truck this weekend - I hate electrical gremlins!!
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Yep, they suck.
Anyway. It feel kinda bad, because the alternator works fine (I am assuming) because they both read the same voltage. Only 12....then they each started dropping. Any suggestions before I start ripping the wire loom off and going crazy? I could start taking the ohms or resistance of the wires as fordeatinz71 mentioned. Thanks
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They don't get much easier than these trucks so go to the junction block and then over to your fusible links.
(http://i6.photobucket.com/albums/y228/Sabaka454/charge.gif)
(http://i6.photobucket.com/albums/y228/Sabaka454/Alternatortest.gif)
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Where is the alternator on the wiring diagram? Could I possibly take the voltages at the alternator and figure out if it is working correctly or not? Thanks
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check the fuse for the gauge or warning lamp, then check your fusible links. Let us know what you find.
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Here's what I visually found ;D
(http://i186.photobucket.com/albums/x285/Trevor2500/IMG_1804.jpg)
(http://i186.photobucket.com/albums/x285/Trevor2500/IMG_1803.jpg)
Looks like a fusible link that was pulled out or maybe it was blown and pulled out. I don't know if it even has anything to do with the charging system, but it looks like it needs to be replaced anyway. Thanks, does that look like it's the problem?
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I'm so sorry for the crappy pics. Not my camera. I should buy one just so I don't have to use that piece of crap any more. Happy turkey day!!! ;D :)
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That looks like the symptom. The problem would be what caused it to melt. Check the wires all the way back around the valve covers and make sure nothing chafed through and shorted to ground. Once you locate and repair the problem replace your fusible links that are toast and locate them away from the exhaust.
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They didn't look melted at all. That one was just sticking out of the fusible link and has some corrosion on it. If you look at the top of the second pic you'll notice a tube for the wires to go in so they don't touch the manifolds. It wouldn't hurt for me to check either. Also, I didn't realize how big the starter was and didn't know the relay or block was right above the starter (looks like a pain to replace). I will check.
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That's the starter motor solenoid. It's mounted directly to the starter. Check those wires behind the valve cover and make sure they didn't chafe through. Make sure you replace the fusible links. If you search here you'll find a few posts on how to replace fusible links.
http://forum.73-87chevytrucks.com/smforum/index.php?topic=5748.15
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does the fuse have to be in a block? Thanks
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huh?
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Like does it have to be in a rubber insulated thing? Or, can I replace it with a normal two prong fuse? Thanks
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You need to use a fusible link not a fuse. A fusible link is essentially a slow blow fuse that will melt and open the circuit before the rest of the circuits branching off of them do. All of your fuses are essentially tapped into these fusible link sources. Modern vehicles use power distribution centers that share a common bus and have MAXI fuses. So Fusible link is the way to go. You can buy them already made or you can solder in your own correct gauge and length of fusible link.
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So, by what your saying is I can buy a new fusible link with wire sticking out of each side. Strip both of those ends. Cut off my old one. Then, solder in the new link and then put electrical tape over it or shrink wrap (I think thats the name). Is that what I do? I am 100% sure. Should I just cut off my old one, then go to an auto parts store and get a new one with the exact same gauge of wire?
Thanks
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i believe what you are thinking is that black hard plastic is the fuseable link, as far as i remember that is not the case. The actual fuseable link is a peice of wire about 6-8 inches long between that black plastic and the starter solenoid.
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It should be the same gauge and length. Heat shrink is the way to go after you make your splices. Get the good heat shrink, it has sealer that comes out when it's heated to prevent any moisture from getting into the wire.
(http://www.sherco-auto.com/fuselink.jpg)
And yes cut it off where the factory black plastic end is.
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did you actually find a blown fusible link? Did you check the one at the junction block on the firewall? You can easily test it with a test light.
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No, I just found the wire sticking out of the black plastic rubbery material thing, and I was told before that that was a fusible link....the same as my 86 Ford Ranger. I was told to tug on each side, if the wire pulls out, then it is blown, if it just stays in the same place....it is fine. I assumed seeing the wire sticking out meant it was blown. Anyway. How do you test it on the junction block? Where exactly is the junction block at? Thanks
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O.K, I tested the hot wire that goes to the alternator from the block on the passenger side firewall and it barely lit up the test light, the same as the one on the right from it. The one on the way left was hot though. So, could that be screwed up? I am going to take it off and clean the wires and what not. Thanks
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Take your test light alligator clip to ground and probe the posts at the junction block bolted to the firewall. The test light should light up on both sides. Carefully pierce the wire with the probe just on the other side of the black capsule on the fusible link. It should illuminate the testlight just the same as it did at the posts. If it doesn't replace the link. Also make sure you check the wires from the junction block forward. Do the same test at the 2 fusible links down at the starter solenoid. Remember the fusible link blew for a reason so find the reason if it is in fact blown before you replace it.
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Take your test light alligator clip to ground and probe the posts at the junction block bolted to the firewall. The test light should light up on both sides. Carefully pierce the wire with the probe just on the other side of the black capsule on the fusible link. It should illuminate the testlight just the same as it did at the posts. If it doesn't replace the link. Also make sure you check the wires from the junction block forward. Do the same test at the 2 fusible links down at the starter solenoid. Remember the fusible link blew for a reason so find the reason if it is in fact blown before you replace it.
Yes, the test light lights up on both sides.
Yes, the fusible links near the firewall junction block light up fine on both sides and the fusible links on both the fusible links on near the starter solenoid light up good too. The fusible links are fine.
I now have a couple of questions.
Am I supposed to be testing this stuff while running?
With a completely charged battery?
I had a spare battery for our camper. Could having those wires connected wrong or anything to do with the spare battery cause failure?
Should I start testing the resistance of wires?
What should I do next?
Thanks, Nova
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Unplug the 2 pin connector at the alternator. Key on Engine off do you have 12 volts at cavity B? What do you have at cavity A? If you touch the test light to the B+ terminal on the back of the alternator there should be 12V there also.
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I have 11.2 volts at the connector on both the wires with KOEO. I have no power out of the alternator (where you plug the connector into) and I am not sure if I am supposed to.
I have no power to the other connector with the KOEO. That is the one wire connector.
So, what shall I do?
BTW - I wouldn't be asking so many questions if my Manual wasn't horrible. The charging system trouble shooting pages were never printed. It skips from pg. 15 to pg. 49. And the trouble shooting pages are 18-19. It sucks.
Thanks
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If you don't have 12 volts at the B+ terminal the red wire single post on the back of the alternator there's your problem. Trace the wire down to the starter solenoid and see where it's open since you said the fusible link is good. Look at the schematic I posted again....
(http://i6.photobucket.com/albums/y228/Sabaka454/charge.gif)
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Here's my problem. Here is where the wire goes. It is the one in the middle. The one on the left is HOT, and both the middle and far right were barely lit up while running. Now, I am not sure where the one on the far right or the one on the far left goes. Or, if the thing is even working. I don't know what it is, is it a junction block? Thanks
Do I trace the wire (the far right one) and find where it goes? The wire in the middle to the alternator is fine, it shows little resistance.
(http://i186.photobucket.com/albums/x285/Trevor2500/IMG_1810.jpg)
(http://i186.photobucket.com/albums/x285/Trevor2500/IMG_1811.jpg)
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Here's my problem. Here is where the wire goes. It is the one in the middle. The one on the left is HOT, and both the middle and far right were barely lit up while running. Now, I am not sure where the one on the far right or the one on the far left goes. Or, if the thing is even working. I don't know what it is, is it a junction block? Thanks
Do I trace the wire (the far right one) and find where it goes? The wire in the middle to the alternator is fine, it shows little resistance.
Hmmmm... trying to follow this post maybe I missed something here but did anyone else see any mention of a dual-batt setup? Looks like that's what you're seeing there in the photos; a battery isolator. Had one on my '77 camper and eventually it went bad. When they're new they work fine providing you followed installation instructions but they won't last forever you know...
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Yes that's an isolator like you'd use in a boat or a camper etc. That's not a factory junction block. The factory junction block was on the firewall and football shaped.
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Yes. Am I supposed to have both batteries hooked up? My junction block is on the other side. And I know what it looks like. I was just trying to figure out why there was no power, and from there where the wires went. What do you recommend doing? Should I see if I am getting power out of the junction block, then see if I am getting power at the end of the wire?
Thanks
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Here's what I think I might try....I'll mark each wire at the junction block (the passenger side one for a spare battery) and connect the wires together using a bolt or screw. Then, I will see if that works. What do you think? I am getting power into the block but the other two aren't?
Thanks
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Are you running dual batteries like for a camper or something off of your truck? if not you can run dual batteries in parallel and ditch the isolator or go back to single battery. Those are basically designed to prevent you from draining down your primary battery. For a quick test jump those terminals together with a jumper wire or put them all on the same peg and see what happens.
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I am not running dual batteries right now. I probably won't either in the future. I will test it tomorrow. Thanks
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O.K, I put all three wires on the same post and it wouldn't even run. I could barely get it started then when it was started it was shaking really bad and then died. So, what should I do next? Should I test the wires? Thanks
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What is connected to your factory junction block? I think you should hook it back up the way it is from the factory and ditch that isolator...
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Oh, I thought you meant hook all the wires up to one post on the isolater on the pass. side firewall. I have a hard time trying to find which wire is which, since 3 or so are red and it goes around the distributor. I will have to (I think) replace the wire then. Thanks
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I've got some questions for you. I haven't looked or touched my truck for awhile due to lack of money and time. Anyway. You said to ditch the isolator, which I plan to do. But I know that one wire hooks to the alternator, one to the spare battery, so where does the third go? I am guessing the third goes to the starter maybe? I don't know. If I loose the isolator, do I take both the used wires and hook them to the original firewall mount...right? Thanks
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Are you running dual batteries? If so just hook the batteries up in parallel and follow the schematic on the other page. It shouldn't be too hard to pull on those wires and trace where they go.
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No, I will never run two batteries...and neither in the future. My truck had an after market isolator. My dad bought a battery tray and used it on the driver side. I don't want two batteries either. Anyway. How do I trace a wire that goes behind the distributor? And, there are 5 (about) of the same size, shape, and color of wires.
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If you aren't running 2 batteries ever get rid of everything that is connected to the isolator and run negative post to the frame rail and run the positive post to the starter.
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There are two positive battery cables, one comes off of the battery and one comes off of the alternator, so where do they go then?
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(http://i6.photobucket.com/albums/y228/Sabaka454/dual.jpg)
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Alright. I took all of the isolater crap off. I still don't get your wiring diagrams. Anyway. I need to know where to hook up the hot wire from the isolater? It looks (I am not for sure) comes from the starter, then does it go the the junction block on the firewall? Thanks
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Well, I got it to I guess barely start, more like stumbled, then died. I tried restarting it and the starter now just spins. It will take a couple of tries before it catches. I held the starter for 30 seconds with the engine turning over and it never did anything. I put some gas in the carb and nothing. I think I just want to get rid of this truck. I am seriously thinking about taking it to the scrapper. I will probably take my other truck along with it too.
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i know i've been out of the loop for a while and i'm sorry, but man, DON'T give up on this truck! you will regret it. i have given up on a lot of my old vehicles and i really wish i could go back and have a second chance with them. i know you've encountered some issues with this truck but you can get around them. it sounds like you've lost spark. you just need to troubleshoot and figure out what caused the power loss (wiring issues, bad coil, bad distributor...etc)
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Yeah. I just have had one of the worst automotive days of my short lift
Last night - Put my dirtbike back together and break the head off of a bolt
This morning - My Ranger is having lots of problems. It cuts out, chugs while driving
Noonish - My Chevy is being a pain in the ass...and won't listen
Afternoon to top it ALL off - I was pissed and tossed my keys at my truck. Hit the front window and put a bunch of cracks in it >:( >:( >:( >:(
That is how I feel. I won't give up on this truck...but that is how I feel. I haven't given up on my Ford yet. That will be first to go if anything. I can't restore my truck right now at this time of my life. So, I am pretty much at a stand still.
Anyway, does anybody have any suggestions on what to do?
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Well 1st you need to chill. Getting frustrated will get you nowhere. If you don't understand something try to analize the situation from a different perspective. These trucks are reliable but when someone goes in and starts hacking away at everything you need to reverse the damage that's been done.
Your positive battery cable goes to the B+ terminal on your starter solenoid. There are 2 fusible links that also connect there. Follow those wires up and verify the continuity to the junction block on the firewall. The other one will go to the bat terminal at the alternator. Once you have that situated and you verify 12V at both sides of the junction block and at the Bat terminal at the alternator you can move on to your other issues.
It sounds like the starter is overrunning and probably needs to be replaced.
If the engine still cranks but won't run check for spark.
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i know it gets frustrating...and i have reacted the same way as you more than once. you just gotta take a break, step back and come back when you are calmer. come back when you have a clear perspective and can actually think to do something about the situation(s) at hand. you'll get on top of it all, just don't do anything stupid...trust me, you'll only regret it in the end...
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Thanks for the confidence. I let my truck sit awhile until today. I got pissed at it and broke the grille...it was already broken, I just broke it worse. Anyway. I tinkered with it for awhile. I dumped gas into the carb and no go. I cranked it over forever...nothing. I hooked up a timing light and checked for spark and I do have spark. I took off a spark plug and long behold it was black. I think I am going to replace them and see if it runs. If not, I think I am going to just start tearing it apart. I should just take off my lift kit and engine, and look for a good truck with a blown engine. I think the plugs will fix the problem though. Thanks. I will report back when I replace them.
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well, just because you have spark doesn't mean you have ENOUGH spark...was it fat and blue? then just look at fuel...is there enough getting to the motor? if you establish those two things, she should fire...the blackness makes me think your carb is WAYYY off though...that will need to be addressed...you are probably flooding the crap out of it...good luck
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Thanks for the reply. I got it RUNNING. It turns out the plugs were completely crap. They were about 6 months old but have went to heck and back. And, I think my alternator problem is fixed....WOOT WOOT ;D ;D ;D ;D ;D
I ran out of gas shortly after starting. So, I will do a test tomorrow. Thanks for all the help. It turns out that the isolator was just junk. I removed it and rewired it and it works fine. I also went through a starter in the process!!! Oh yeah!!! ;D
Now, I just need help getting my steering issue solved, and I will be an extremely happy chevy owner
Thanks for sticking with me and giving me the advice. You guys are great.