When i bought the car, it seemed to be running ok. And when i went to tidy up the engine bay, the main prob was the wires. I guess alot of the wires had been cut at one point, so the previous owner spliced in random peices of different coloured wires for anything from alternator output, to ignition switch wire, to headlight wires. When i got the car, i took those crude wires, replaced them while trying to match the gage of the wire to whatever it was spliced into. I also tried to colour co-ordinate them and put butt connectors at the end to make it safer. I also directed them away from the headers. The car ran great after i neatened it up, but recently i learned something else. My car does not charge the battery!. So here is what i checked. First i checked if the alt. was charging. Simply enough, i accidentally grounded the positive output on the alt while trying to splice in an ammeter, and sure enough i got a huge spark. ou: YEP! it was charging. So my alt is good. Next i took a wire and spliced it from my alt output, to my positive battery terminal, to charge it manually. Went for a drive, and when i stopped, i disconnected that wire and tried to start the car, it still didnt have enough juice. Its very annoying, so here is what i need, before i can afford a new chassis wiring harness. Can someone plz send me, or tell me where to find a basic buick skylark (1971 350) charging system wiring diagram? In it, i just need to see how the wires are routed from the battery -> Starter -> ignition switch -> alternator -> ignition --> back to battery? The car starts off the battery and runs off the alternator, but when the battery is dead, the alternator output is not sufficient to idle the car, above 2000 rpm is ok though. Thanks
azeem,just because you have power at the back of the alternator,doesnt mean its charging.that lead is hot all the time!!! its the feed from the battery straight from the starter.basically its power IN not out.the charge circuit is completed thru ground.i dont have a 71 book,do you know if you have the built-in regulator or is it on the firewall? 71 should be on the firewall.p.s. you may have damaged the alternator when you grounded it :error:
Azeem, You are really going to need a factory service manual. You will find it invaluable in your wiring gremlins. I know you just want free info, and I am not knocking that. But from someone who has been there, the FSM is like a godsend.
Hi Azeem. I agree with the above. A workshop manual is a must if you really want to enjoy yor car. It make life more interesting when you actually know what you are doing. You also need a multimeter to measure voltage & ohm. With the engine running at high idle, (approx 1000 rpm), you should ideally read 13,7 voltage at the battery. Anything under 13,2 volt indicate a bad charging system. Could be either the alternator, the regulator, (If this is seperate from the alternator), or something with the wiring. If you have above 13,2 volt when running, I would guess you need a new battery. Per. :beer :beer
Azeem, I would suggest you break down and call Factory Fit and buy an entire engine wiring harness for your car. Worth every penny and everything lines up and plugs right in where it should. Good stuff. Your playing with fire with Mickey Mouse stuff. Many cars have burned to the ground because of amateur hack jobs.(not you, the last guy) but now you have to deal with it! Better ride with a fire extinguisher next to you otherwise.
Azeem, Make sure, whatever you do, to check the fusing in the fuse panel, under the dash. Put in only the max. fuse sizes per the manual. Once your harness is repaired/replaced you don't want a 30A fuse behind wiring & devices only rated for 10A. Many times owners will hack up the wiring by adding accessories, short cuts elsewhere.Fuse blows? Just put a bigger fuse in right? Once you put the rated fuse in place & it blows, a this is a good sign. System is telling you there is a problem ......somewhere.You need to correctly remedy it. Pretty cheap insurance in my books.
Thanks guys, you got me when you said im just trying to get free info Actually the last time i went to look up those manuals, aside from being rediculously expensive, i was having trouble with the shipping and stuff. Is there some place in ottawa or close to where i can get it? I think it would be a good investment as well. It would really suck if the alternator is damaged, its an original peice. The grounding time was only for a split second, so hopefully its still working. I beleive the regulator for the alternator is on the firewall, because the original wire off of the output is a rather large gage. Steve i have been told many times about the fire hazards, and because of that, i have replaced all of the fuses and any old looking wires. Ive made sure not to leave any exposed wires, and in addition ive added a few fusible links to the car as well. The reason im trying to fix this "half assed" at the moment is because i cant afford the wiring harness just yet. Although that would be the ideal fix. I was looking at the price list for the Painless wiring, and it was something like $400! Way out of my reach, i can spend maybe $80 cdn. on some new wires and and things. I was hoping i could get the diagram, so i could rewire the car with brand new stuff from the battery to the ignition and everything in between. Does someone have a used manual,or know where i can get one without the use of a credit card? Thanks again.
jamie, you mentioned that the output is actually and IN??? when the car is running, there is definately electricity coming out of that post on the alternator. You also mentioned that the charging is completed through ground? The ground post on my alternator is bare, there is no wire going from it to anywhere. I asked about that earlier, and the board members told me it did not need to be grounded because the alternator is grounded through the engine by being attached to it. Could you elaborate a bit more on this? Thanks.
I have a '71 Chassis manual. I'll try to copy a couple pages & send them to you. Send me a fax # as posting here usually too small to read. Engine harness '71 350. I have another original harness I will be installing in my own car shortly.Mine has a bit of heat damage. I'll look at it next couple days & fill you in on who goes where.
fax # is same as my phone number, but its not on all the time. Try 613-741-7517 around evening time. You will probably have someone answer the phone. OR you can tell me a time you will fax it, and ill just leave it on at that time. Steve, where did you get your manual?
Azeem, Sent you some wiring diagrams. Much better than the black and white in most manuals. Find a good shop that rebuilds alternators and starters. I just had an alternator done for a 65 Mustang that needed more amps because of an electric fan. They jumped it from 55 amps to 110 and charged me 30 bucks. I will never buy a new alternator again. Check with a good parts shop and they may be able to clue you in.
get a cold one & be prepared to be edemecated! the ground post is grounded to the case.so with two mounting bolts holding it in place it is grounded quite well.i dont know why delco put the post on there,other than to hold everything together. i have seen very few of them actually use it in 25+ years of rebuilding.so we have power (dc)going to the battery terminal of the alternator(in)the alternator converts it's ac to dc,it goes out through the ground circuit(the case) to the ground of the negative cable,usually bolted to the alternator bracket(aha,ever wonder why the ground is so close to the alternator?)back to the negative side of the battery,completing the circuit.in between that path,it also is flowing to the accesories ground side.if you ever took off your negative cable while running/charging(DONT EVER DO IT! IT CAN DAMAGE THE SYSTEM!)) & put a voltmeter on it you would see infinate voltage(controlled by rpm)at the end of the ground cable.the current path is trying to be completed(looking for a home,so to speak)in the biz we call this transient voltage.so,you can see you dont have power flowing out of the back of the alternator.it is only part of the pathway.and yes,it is powered ALL THE TIME as it is a tap right off the positive battery cable.when you grounded the post,you sent the full capacity of the battery amperage(300-400) to ground.the diodes in the alternator are rated at 25 ampres,this means anything over 25 amps will "leak"(go the wrong direction)usually shorting a diode of oposite conductivity,allways taking the path of least resistance,usually the closest or smallest wire.thats why the fuseable links are located at the juction of the battery pos cable & alternator/accesories feed.it wont do it in normal operation of charging,because you have 3 phases each with a neg & pos diode meaning 75 ampres of protection.the alternator is rated at much less than that.in the hi amp alternators of today,the diodes are rated higher & some have 12-14 diodes(which is basically a one way switch).the reason you have 13.8-14.2 volts charging is to power the accesories,lights,coil etc,and to overcome the resistance of the current pathway.the alternator is there to power the accesories,not charge the battery other than a trickle.there,anyone confused yet? :laugh: my head hurts :Comp:you all can send me money now for the lesson :laugh:
Azeem, Here are a few pics for '71. Chassis manual from Y-1, just after I bought the car. Excellent reference. No good, too small. I'm not sure my modem will want to talk to your fax if you need to pick up & press start. Send me a PM & I'll mail you some copies.
BINGO! Thanks jamie, i learned a good deal from ur lesson, and i think i may have found where i made the mistake!!!! My Negative battery terminal was grounded in the past to the alternator bracket, it was the ugliest thing i ever saw, and was really in the way! I figured most of the wiring was screwy, this was prolly just a half assed job. SO i regrounded my battery to the core support. You think that would do it???? I would like to keep that big ugly wire where it is, if this IS the prob, you think if i ran a wire from my GRD alternator to the Negative battery terminal it would solve the prob???? Thanks for all ur help, you might have just saved me TONS of trouble.
read thru it again,the neg cable is supposed to go to the alt bracket.it is grounding the entire block.this bracket is aluminum in most cases,bolted to iron.mating surface must be clean,scrape paint & rust & use a dielectric greaseto keep connection clean.you can bolt it anywere you want as long as its to the block!then on the back of the passenger side head you should have a braided strap going to the firewall to ground the body to the block.a lot of guys leave this strap off,but can cause multiple problems if missing.is your alt idiot light on?does it work?when you turn the key on it should light up.if you have a voltmeter,with the car running put your neg lead to gnd side of battery post & pos to pos side post of battery.note voltage.do the same only touch the leads to the cable ends.should be same reading,if not,bad battery connections.now leave gnd were you have it & put pos lead of meter to post on back of alt.note reading,can only be 1/2 volt difference if any.if that checks out move the gnd test lead to block,take both readings again,they should be the same,if not you have a bad ground.this is assuming both alternator & regulator are working properly.bring it over,ill look at it :laugh:
While detailing my engine, i did notice the ground strap from the block to the firewall, it is on securely and cleanly, all my idiot lights work fine. I will scrape the paint off the alt bracket, and put my negative battery terminal back on there. Hopefully this will solve the prob. Thanks again for all the help, ill let you know how it turns out.
That was the prob. My alternator was not grounded properly. I had painted the bracket and when i bolted it to the block, there was too much paint and not enough metal to metal contact. So i buffed it down to bare metal, and bolted it on. I also buffed the negative batter ground and bolted it to the alternator bracket. And painted over all the bare metal AFTER they were bolted on. Seems to be working great now, no charging probs. Just gonna put the multimeter at the battery to make sure, will let you know what i find.
i just got done wire wheeling all the bracket contact point with a dremel tool on my motor last night.freshly painted of course :laugh: guys,dont forget to do this after painting a motor,its a lot easyer when its out :TU:
actually they are new bolts,except the ones i painted white(oil pan) p lets just hope it runs as good as it looks :TU:
