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-   -   no interior lights, now car wont start (https://www.corvetteforum.com/forums/c3-tech-performance/4055035-no-interior-lights-now-car-wont-start.html)

target30 10-16-2017 11:24 AM

no interior lights, now car wont start
 
ok, first off, you guys were a great help on the fuel pump issue. i figured id start a new thread since this is a different issue.

forst the story, fuel pump wasnt working, turned out to be a DOA new pump, car would start, for a second, with fuel in the carb. once i got that situated, the carb started pumping fuel out the top. pulled to float bowl, cleaned it out, and it seems to be ok.

now the problem. sometime during the numerous time i cranked the car over and over, the interior lights(courtesy) stopped working. at around the same time, im guessing, the car stopped trying to start. it will crank and seems to want to start, but never gets there. can these 2 things be related?

wanted to add, all exterior lights work(as well as they did before!) i have a wiring diagram but it is a little blurry and hard to read, and i havent found where these would be related from the diagram. also, i didnt see any blown fuses, unless there is another fuse box than the one under the drivers side dash.

71VetteLover 10-16-2017 12:11 PM

I would start by taking the battery terminals off and clean the battery posts until they're bright and shiny. I use one of the inexpensive twist type wire battery post brushes that can also clean the inside of the terminal. Less than $5 and available at any auto parts store.

target30 10-16-2017 12:13 PM

i actually replaced the battery because the old one had been charged and discharged so many times it was shot. so i cleaned the contacts when i put the new one in.

MelWff 10-16-2017 12:26 PM

you flooded the engine, did you pull the spark plugs and check if they are gas soaked and allow the cylinders to air out?
somewhat related, did you check if your oil smells like gasoline, if so, change it.

target30 10-16-2017 12:40 PM

i have not pulled the plugs. i will do that tonight. So the interior lights and the car starting are likely a coincidence?

7T1vette 10-16-2017 02:33 PM

With engine OFF, turn on the headlamps (need them in UP position to see how light intensity changes). Now try to start the car. If the headlamps do not dim, you have a problem with battery/ground cables and/or connections. If the lamps go really dim or go out completely while cranking, your battery is SHOT.

[Headlamps can be used as a 'cheap' ammeter for diagnosing problems, sometimes.]

target30 10-16-2017 02:57 PM

its a brand new battery as of yesterday, cranks great. i just put a multimeter on the coil with the key on and engine off(obviously! haha!). 12ish volts on the positive side, nothing on the negative. im to understand i should have power on both sides with key on and engine off.

target30 10-16-2017 03:08 PM

its also pretty safe to say that "uncle bubba" had his hands in the wiring....however it did run fine before the fuel pump went out, and i havent touched any wiring, aside from changing the battery, from then to now.

target30 10-16-2017 03:39 PM

sorry to keep posting, but im trying to give all the info i can. from the wiring diagram, a black/pink resistance wire goes to the coil. mine is black. and pretty thin. i can see on the fuse box the black and pink wire, but cannot find where it goes. it also looks to be in fine shape.

MelWff 10-16-2017 03:58 PM

you should have a double wire on the positive terminal of the ignition coil, are you saying you dont?
The negative terminal should have a single wire going to the distributor.
This assumes you have the stock points ignition used in 1973.

target30 10-16-2017 04:02 PM

yes, double wire on the + side, one is a thin black wire heading into the firewall, which i thought should be the black/pink. cant remember where the other one goes at the moment. i can go back and a look. then a wire from the - side going into the distributer.

everything worked fine until i was working on the fuel pump, and cranking it excessively. im guessing i melted or fried a a wire somewhere, since the interior lights are out, and now im not getting power to the coil.

target30 10-16-2017 04:58 PM

so, upon further inspection, the wire from the - side of the coil, was spliced into a wire coming from under the dash, that went to the distributor. that is not at all what the wiring diagram shows. for a moment, i was showing 26v at the + side of the coil, but couldnt replicate it. still nothing on the negative side. this is a newish coil btw. and like i said, it did run before on it. i removed the splice and ran straight from the coil to the distributor. no change.

The key warning buzzer still works, still no courtesy lights, and nothing on the - side of the coil. i did notice the acc pin(just above the ign pin with the pink/white wire)on the fuse box had a brown wire coming out, with a connection in it, and there was some melting on the black connector part(not against the fuse box, but about 3 inches down the wire) and it looks like a wire once was soldered onto it, but i cant find that.

my wiring is a mess, but it did work before....there must be something melted or grounded out. i could probably rewire the car int the time it is taking me to search all this out...

so back to the original issue, no courtesy lights, no power to - side of coil. can they be connected? or coincidence? i'll take the car starting over the courtesy lights at this point, but i have a feeling these are connected.

for info, im using this wiring diagram...

http://www.keystonestatecorvetteclub...tte%201973.pdf

TimAT 10-16-2017 05:42 PM

The only place the wire from the - side of the coil should go is to the distributor. Or maybe also to a noise suppression capacitor mounted right on the coil.

target30 10-16-2017 06:07 PM

i made that change, but still no different. im going to test the resistance on the coil, to make sure it is good. but im guessing, if the + side has something, and the - doesnt, and there isnt a ground wire, it must be bsd? idk honestly.

target30 10-16-2017 06:43 PM

so i tested the coil. 12v at the + side, nothing at the -. i was able to get 26v at th + side again, then when cranked it went back to 12. when cranking, i got about 7v on the - side. i tested the resistance on the coil, and got 2.1 on the main coil, and 8 on the secondary( + side and center). that seems low to me.

TimAT 10-16-2017 08:25 PM

The coil - wire goes to the points. Pop the cap and check the wire to the points end to end. THe points could be closed up or the condenser went bad. I've seen the distributor wire bad too.

henrikse 10-16-2017 11:56 PM

1 Attachment(s)
Pull a plug wire and hold it close to manifold to see if you have spark? There is a fusible link by the horn relay. I am looking at 73 wiring but if you look at the attached diagram the black/pink you mention goes to this fusible link

MelWff 10-17-2017 11:31 AM

Negative coil wire
 

Originally Posted by target30 (Post 1595777016)
so, upon further inspection, the wire from the - side of the coil, was spliced into a wire coming from under the dash, that went to the distributor. that is not at all what the wiring diagram shows. for a moment, i was showing 26v at the + side of the coil, but couldnt replicate it. still nothing on the negative side. this is a newish coil btw. and like i said, it did run before on it. i removed the splice and ran straight from the coil to the distributor. no change.

The key warning buzzer still works, still no courtesy lights, and nothing on the - side of the coil. i did notice the acc pin(just above the ign pin with the pink/white wire)on the fuse box had a brown wire coming out, with a connection in it, and there was some melting on the black connector part(not against the fuse box, but about 3 inches down the wire) and it looks like a wire once was soldered onto it, but i cant find that.

my wiring is a mess, but it did work before....there must be something melted or grounded out. i could probably rewire the car int the time it is taking me to search all this out...

so back to the original issue, no courtesy lights, no power to - side of coil. can they be connected? or coincidence? i'll take the car starting over the courtesy lights at this point, but i have a feeling these are connected.

for info, im using this wiring diagram...

http://www.keystonestatecorvetteclub...tte%201973.pdf

The other reason you would have wire going from the negative terminal of the coil to both the distributor and through the dash is if someone put in a crude anti-theft device. If that additional wire goes to a toggle switch and the other side of the toggle goes to ground that switch would kill your ignition. That additional wire could also be used to work with a electric tachometer. In any case the wire should not be there.

target30 10-17-2017 01:17 PM


Originally Posted by MelWff (Post 1595781533)
The other reason you would have wire going from the negative terminal of the coil to both the distributor and through the dash is if someone put in a crude anti-theft device. If that additional wire goes to a toggle switch and the other side of the toggle goes to ground that switch would kill your ignition. That additional wire could also be used to work with a electric tachometer. In any case the wire should not be there.

you know what, there is a switch that killed the engine...i never used it. interesting, at least i know i can pull it out now. it did pull the coil wire off of it. im going to run a test on the fusable link to see if maybe i cooked it.

target30 10-17-2017 04:28 PM

ok, so im headed in the electrical direction at the moment. i think my coil is bad due to the low readings i got, but once i figure out the electrical, i think the ignition will also be fixed.

i pulled the courtesy light bulb holder out and tested it, im getting 26/27v on the white wire. i'm also getting 27v on the pink/black wire thats supposed to go to the coil per the diagram. it must be spliced into a black wire at some point, because it is black at the coil. anyhow. why am i getting 26v? this should be 12 should it not?


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