Home page

Topic: 1969 427/390 battery/alternator/electrical?

in Forum: C3 Electrical


Already a Member? Click Here to Login
Not yet a Member? Click Here to Register for Free!
1969 427/390 battery/alternator/electrical? (1/8)
 2/4/21 1:34pm
motocarlo
Limited Member
Send Private Message

Culver City, CA - USA

Vette(s):
69 L36


Joined: 2/3/2021
Posts: 4

hi guys

happy to be part of the forum and thanks for having me. my name is Carlo, i’ve just acquired a matching numbers 1969 L36 in Riverside Gold.

When the car was dropped it wouldn’t start out of the trailer.....had to push into my garage. :( 

Car would not even try to turn over, and taking a look at the battery I noticed it was from 2013. With the ignition on the windows closed super slowly. The owner had the car on a trickle charge and sent video of it being driven and loaded onto the trailer. 

I was able to get the car jump started after booking it up to my truck battery and letting the trucks motor run for about 5minutes. Took the car out and it ran fine for about a 25minute ride. Parked her for the night. 

Next morning car started fine, went out to try and find a new battery as that’s what I thought could be eliminated first. couldn’t find one, put the car back in garage but this time on a charger. Initial reading on the battery was 12.3~12.4 but went up to 12.7 once charged. 

Next day went to try and start her up but was just about there but not turning over. Noticed the charger was on maintenance mode. Switched it over to charge and car started right up. 

Put in a new Interstate GreenTop battery, and car ran fine from parts store. Kept it off charger overnight and went to start next morning......would not turn over. Voltometer reading 12.4 on the new battery. Once I let it charge for about 2-3minutes car started right up. 

Seems like the battery is not holding charge so either issue with alternator or a parasitic drain on the battery but I am no expert ......what do you guys think? 

 

thanks in advance !

 

 

 

 

 

Our Sponsors help support C3VR
Re: 1969 427/390 battery/alternator/electrical? (2/8)
 2/4/21 3:26pm
motocarlo
Limited Member
Send Private Message

Culver City, CA - USA

Vette(s):
69 L36


Joined: 2/3/2021
Posts: 4

some more info: 

Battery is reading 13 volts this morning. 

Car will not turn over until battery charger is in charging mode. Will not turn over in “maintenance mode”. 

When car starts battery voltage drops to about 12~ volts. 

After starting voltometer reads 14.6 at idle. 

Re: 1969 427/390 battery/alternator/electrical? (3/8)
 2/4/21 11:02pm
Adams' AppleLifetime Member
Lifetime Member
Moderator
Send Private Message

Duncanville, TX - USA

Vette(s):
#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas


Joined: 11/8/2003
Posts: 19854

Sounds like you have a bad connection, either at the battery, or at the starter. Corrosion can do stuff like this, as can loose connections. I'd suggest checking ALL of the connections from the battery to the starter, including the grounds. 



______________
Joel Adams
C3VR Lifetime Member #56    

My Link


(click for Texas-sized view!)
             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
Re: 1969 427/390 battery/alternator/electrical? (4/8)
 2/4/21 11:13pm
73shark
Limited Member
Send Private Message

Overland Park, KS - USA

Vette(s):
1973 Orange Metallic Coupe (orig owner), L82, 4 spd (WR), PS, (A/C & PW (I installed from wrecked 73)), leather, AM/FM Stereo, ran with '65 FI unit earlier & will again some day.


Joined: 7/9/2003
Posts: 692

First, Welcome to The Forum. Second you can take your battery to most auto parts stores and they will test it for free. However I suspect you have some type of drain that's discharging the battery overnight. You can check this by placing an ammeter between the positive post of the battery and the disconnected positive cable with everything off. If there is a drain on the battery then the best way to find it is by pulling one fuse at a time to see which circuit is causing the drain.



______________

1973 L-82 4 spd

Re: 1969 427/390 battery/alternator/electrical? (5/8)
 2/7/21 12:15am
motocarlo
Limited Member
Send Private Message

Culver City, CA - USA

Vette(s):
69 L36


Joined: 2/3/2021
Posts: 4

thanks guys for all the responses. 

installed new battery and i’m getting good readings on the voltometer when car is running (14.6) and when car/battery is cold (12.6-12.9). 

car will crank but not start after sitting overnight. what I did notice is that car will turn over if I give it a little bit of gas. im

not sure if this is of great significance but the car came from altitude out of state. i’ve noticed while running that the car has a bit of hesitancy when first pressing on the gas while driving/accelerating. 

could it be that the fuel/air mix is just off and carb needs rejetting? too much air in the mix to start the car? 

 

thanks again all



|UPDATED|2/6/2021 9:15:34 PM (AZT)|/UPDATED|
Re: 1969 427/390 battery/alternator/electrical? (6/8)
 2/7/21 12:00am
73shark
Limited Member
Send Private Message

Overland Park, KS - USA

Vette(s):
1973 Orange Metallic Coupe (orig owner), L82, 4 spd (WR), PS, (A/C & PW (I installed from wrecked 73)), leather, AM/FM Stereo, ran with '65 FI unit earlier & will again some day.


Joined: 7/9/2003
Posts: 692

Probably should have led with the fact that it will turn over but not start unless you pump some gas in it. First thing you should check when the engine is cold is to be sure that the choke is fully closing when you push the pedal to the floor and release it. That does two things. It both adds fuel from the accelerator pump to the intake and reduces the amount of air when starting creating a rich mixture which is required for a cold start. I say this not knowing if your engine is stock. 



______________

1973 L-82 4 spd

Re: 1969 427/390 battery/alternator/electrical? (7/8)
 2/7/21 12:11am
motocarlo
Limited Member
Send Private Message

Culver City, CA - USA

Vette(s):
69 L36


Joined: 2/3/2021
Posts: 4

thank you for the reply.....i did not attempt adding gas while cranking until today...silly I guess but I was down a rabbit hole of what I assumed was a charging/electrical issue. 

engine is completely stock. how could I go about checking the choke?



|UPDATED|2/6/2021 9:11:17 PM (AZT)|/UPDATED|
Re: 1969 427/390 battery/alternator/electrical? (8/8)
 2/7/21 1:21am
73shark
Limited Member
Send Private Message

Overland Park, KS - USA

Vette(s):
1973 Orange Metallic Coupe (orig owner), L82, 4 spd (WR), PS, (A/C & PW (I installed from wrecked 73)), leather, AM/FM Stereo, ran with '65 FI unit earlier & will again some day.


Joined: 7/9/2003
Posts: 692

First remove the air cleaner. This must be done while the engine is cold. Preferably an overnight sit. Then while you are watching the choke valve on the carburetor, have an assistant floor the accelerator pedal and release it one time. The choke valve should close completely when this happens. If it doesn't, then it needs to be adjusted. Pushing the accelerator pedal to the floor does two things. One that closes the choke valve and two it causes the accelerator pump to pump a shot of gas. This is pretty much the cold start procedure for most modern carbureted engines.  Curious as to wondering if that's the procedure you were using when it wouldn't cold start.

 

It would probably be a good idea to do a complete rebuild on the carburetor anyway unless it's been done recently. Then go through the service manual procedures and check all of the adjustments on it.



______________

1973 L-82 4 spd

Our Sponsors help support C3VR