Okay here is what we are dealing with. It is a 68 chevy c-10 with a 305 from a 83 monte carlo. But me and my dad (me the one buying the parts and doing the work 2) have been trying to figure out why evertime we turn on the headlights the truck dies. Okay at first the truck wouldnt stay on even stay on when you turned on the parking lights or put it in gear. And we had a bad dimmer switch that we knew of. So i ordered one of those and replaced it and that didn't work. So next my dad said well the headlight switch is a little messed up. So then i ordered that and replaced it and that didn't work. And like i told my dad from the begining it has to be the alternator. So finally my dad agreed with me. So we took the old one down to autozone to get it tested and sure enough it was bad. So i bought and new one and put it in yesterday. But now you can put the truck in gear and it will stay on, you can even put the parking light and it will stay on, but when you go to put the headlights on it dies out. The only way it doesn't die out is if you give it a little gas while it is in gear. So people please help me what do you think i need to replace next. I can't figure this one out.
Hmm, 1st the obvious, belt tightened enough? idle high enough? all connections tight? enough ground? As for 2nd was the new alternator tested?
Yes the belt is tightened enough. It is idle high enough. As for the connections which ones? and there is only one ground to the block we are thinking about running one from the block to the frame. And no the new alternator isnt tested that i need to do.
Set e brake, fire up in park, Turn up idle setting on carb till it will stay running in gear first. Take volt tester to battery ( engine running) should have 13.5-14.5 volts if you did the alt right. Ancient wiring harnesses can be a can of worms. Hei or points? Hei needs a dedicated source of 12 volts, not ****ty old points ignition wiring with resistance built in. Safety first!
okay i will try that sawracer. and it is stock points but we put in a pertornix kit to convert it to electronic and it was doing fine before but all of a sudden it started doint this out of no where
In reality, if everything is right, and the alternator goes bad, you could still run it off the battery for a while. Are you having to jump start it? Have you checked the voltage? A fully charged 12 volt battery will hold 12.5 volts with the engine off, with it running it should be 13.8 to 14.2 if I remember correctly. Get a volt meter and do some diagnosing. Also, batteries can have funny **** go wrong inside, might want to try a known good battery, like out of your daily.
Well we dont have to jump start it. And the battery in this truck is from a daily we drive our cars not park them. Also my moms battery in her durango went bad and this battery has been in there and the durango starts up no problem. the volt meter on her durango reads about 14.
51Caddy, I had a very similar problem with my '67 Pontiac wagon. I converted over to a Pertronix "plug and play" distributor and it would start great every time and die every time I put it in gear. Turns out as mentioned above, HEI HAS TO HAVE constant 12 volts. If it drops to 10.8 or below, (per the tech at Pertronix) it will die. Will re-start every time, but dies when in gear. I'm betting money when you pull the headlights on, it is dropping the voltage. Run a dedicated wire with constant 12 volts and you should solve your problem. 51FourDoor
Well 51fourdoor, How would i go about doing this. This sure sounds like the problem to me because now that there is more power in the alternator it is keepint it in gear and the parking lights on but with headlights it dies. So can you please explain to me more about how i will go about doing this thanks, 54Caddy
51Fourdoor has solid advice, it's where I'd start. Where does your battery ground cable bolt to? The engine or frame? I'd add a ground strap (engine to body) if it's on the engine. I'd add 2 ground straps (engine to body plus engine to frame) if it's on the frame.
51 Fourdoor is right on the ****on with his advice on the constant 12 volt source, and Shifty is exactly right when he tells you to ground that thing at least 3 ways. I've seen many old cars and trucks burn to the ground because they trusted the ground from the battery to the engine to do the entire job. They didn't stop to think that the engine mounts are rubber, which doesn't conduct electricity very well. I ground mine as many places as I can to ensure I don't have to worry about a poor ground causing me electrical problems. You need your battery grounded to the engine, your engine to the frame, your engine to the body, and the battery should really be grounded to the body and the frame also. Good luck in getting your truck figured out. Jerry
I dont have a pertronix diagram, but you must still have yours if you just put it in. There should be a battery or power lead for it. Un plug that wire from what you have it hooked to, and connect a wire from there to the bat + on the ignition switch, back of the alternator where the battery connects, , +battery terminal...any thing that has constant 12 volts. That will byp*** your wiring and if it keeps running in gear, you found your problem. You should also run a ground from battery to block, like you have, and from block to frame. Block to firewall wont hurt either.
Alright deserratrodder can you explain that again i kind of dont get it that much. But yes i will run more ground like you guys say.
run a wire to the bolt on the back of the alternator,hell try the battery ,if you truly get confused try to find some more or less experienced help from your car club if not you are going to burn your car up and that would be a shame.
The main wire on your alt. should run directly to your battery or some other junction with a constant power connection. Your voltage should be highest at that point, so that will confirm if the problem is voltage to the pertronix.
yeah but understand that might make your car run after you turn off the key,I would try it though should get full voltage.I ran aPertronix on my LTD and I used a relay that activated from a 12V switched lead and was hooked to the Battery.Key goes off so does the car.my ignition didnt give full 12V at the distributor.
Do you have a volt meter? If you do not, or dont know what that is, stop until you get one. Not bagging on you, you will need one to understand what we are telling you, as far as finding a 12 volt source. Do you have the directions for the pertronix kit? If not, find them. They will tell you what wire is the power wire for your distributor. When you find that wire, disconnect it where it is plugged into or spliced into your harness. If you cut it, make sure you leave enough on both ends to re-connect it later. Make sure any other wires going to the distributor, if any are still hooked up. Get yourself a length of wire as close to the size as the one on the distributor as possible. I mean thickness. connect one end to the wire going to the distributor. With your volt meter, you should be able to find a 12 volt source. If you do not have a volt meter, connect it to the + post of the battery. Turn the key like normal, and the engine should start. If it keeps running after you turn off the key, unhook the wire you just hooked to the battery. You dont want to leave it hooked up like this forever. This is just to diagnose a problem between the ign switch and the distributor.
Desert Rat is correct. here is where your problem is. The original wire running to the coil on your points distributor is a RESISTOR wire- meaning it will only carry a certian amount of voltage and amperage. 9 in your case. 9 volts will allow for the petronix to run...but not as well as it should. and what i imagine is happening is this...you pull the headlight switch out, they voltage and amperage draw is pretty high for a second or two...just long enought to put the fire out in your distributor. either that, or some "creative wiring" under the dash has allowed for the headlight switch to steal power from the ignition terminal on the ignition switch...weirder things have happened.
How about if you just put the points back in and see if the problem is still there. If the problem is gone call petronix and tell them you want a refund then take the china rebuilt alt back to auto zone and get your good old american one back and tell them to quit selling alt's that people do not need
Alright check out what i did. I let the truck get very warm so the belt was spining perty long. then i checked if it was snug and there was hella slack in it, so i tightened it and there is no problem no more. It must have been like cold or something when i put the belt on because me and my dad snuged it up hella tight the first time but now it is good and running perfectly. But i am going to put more ground still just in case but thanks for all your help guys
Did the person who put the 305 in keep the HEI, and if so, did they install a NEW wire for the distributor power source? Some of these GM cars with a points setup have a resistance wire that drops the volts some, they don't use a seperate resistor. So you need to change that wire if the truck's going to run right with the late HEI setup in it -
NO the HEI was not droped in when my gramps and my dad put the motor in. They put the points system back in it. But then later my dad wanted it electronic so we converted it with a petronix kit. But it is running perfect now. I will take some pictures soon
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