Car stalls when cold after alternator problem - please help
08-31-2023, 08:58 AM
#1
Junior Member
Thread Starter
Join Date: Aug 2023
Posts: 1
Likes: 0
Received 0 Likes
on
0 Posts
Car stalls when cold after alternator problem - please help
First things first: this is about my 1986 Chevrolet Caprice - NOT a Camaro of Firebird. If this isn't allowed here - I apologize and understand my post will be removed. However, I am in dire need of help and came to this forum due to the similar engine / carb setups on your third gens.
I am a young guy from Europe and recently bought a 1986 Caprice Brougham with a 305 V8. I believe it is bone stock and has the Computer Command Control Quadrajet carburator. I bought the car and drove it 100 miles home. No issues at all, except the engine feeling a bit flat going uphill. Took it for a few more rides and still no issues.
The issue
Then, as I was out cruising with friends, the alternator died on me. I pulled into a parking lot, shut the car off and it had zero juice left. Couldn't even put my windows back up, let alone crank the car. I replaced the battery the next day so I could drive it home. But when I started the car with the new battery in it, it kept wanting to stall. I had to keep my foot on the throttle for 2-3 minutes before it finally settled into an acceptable idle, and drove home with the dead alternator still in it.
I had the alternator rebuilt, but when I put that one back in, it still didn't charge the battery. It turned out the cable from the positive battery post to the alternatour output post melted or corroded through, so I fixed that. But even then, the alternator still didn't charge the battery. I believe the damaged cable was the original problem, which fried my alternator twice.
Yesterday, I put in a brand new alternator, and the car finally charges again. Yay! BUT, the car still runs like crap and it keeps wanting to stall, unless you feather the throttle and give it CPR for 2-3 minutes.
My car has now been sitting in my garage for 2 months, and I missed an entire summer of cruising, which was the reason for buying the car in the first place.
It is my understanding that incorrect alternator output voltage can cause a rough idle and stalling, so I was pretty confident that finally fixing the alternator problem would also solve my stalling problem. Especially giving that these 2 problems occured at the same moment. But I was wrong.
Additional info
- Full service manual for reference: Repair and Diagnosis — 1986 Chevrolet Caprice V8-305 5.0L Service Manual | Operation CHARM
- Electric choke seems to open like it should.
- Choke pull-off holds vacuum - I feel like it cracks open the choke a bit too much on initial startup, but I never touched the adjustment screw, so I don't think this is what causes my problem.
- I cleaned the EGR valve. It also holds vacuum.
- Throttle position sensor is within spec.
- No check engine lights. I tried reading codes, it only reads code 12, but that was after the engine only ran a few seconds and stalled. Not sure if it should run it longer in order to retrieve the codes.
- When I jump the diagnostic connector, there is a very fast clicking sound - almost buzzing - coming from a white connector on the passenger side of the distributor. I've been told that the diagnostic mode will typically power some relays, but I haven't heard this sound in any of the OBD1 videos I see on YouTube. To be clear: It is not the mixture control solenoid which normally clicks with key on and engine off. I know that sound.
- Starting procedure I use is exactly what I used before the issues arose: Depress throttle once to set choke closed, turn key and voilà. Car cranks with plenty of speed / power.
- Car is usually harder to start after it stalls the first time. Simply turning the key usually isn't enough at that point, and I have to depress the throttle as I crank for it to start.
- The first few seconds after it cranks, the engine usually runs fine. It will, however, always stall quickly if I don't do anything, but it will stall instantly when I give a bit of throttle. RPM's go up and then seem to just drop through the floor and stall the engine.
- If I am able to get it to idle after a few minutes, it sometimes also seems to increase RPM's by itself. I usually shut it off quickly after that as I am afraid it will get worse.
- Before the alternator issue, I remember a few times where the aftermarket radio would continue to be on after taking the key out. I have not used the radio since then but I remember being surprised.
Any input is much appreciated. I am at a bit of a dead end here and need some fresh perspectives. Thank you!
I am a young guy from Europe and recently bought a 1986 Caprice Brougham with a 305 V8. I believe it is bone stock and has the Computer Command Control Quadrajet carburator. I bought the car and drove it 100 miles home. No issues at all, except the engine feeling a bit flat going uphill. Took it for a few more rides and still no issues.
The issue
Then, as I was out cruising with friends, the alternator died on me. I pulled into a parking lot, shut the car off and it had zero juice left. Couldn't even put my windows back up, let alone crank the car. I replaced the battery the next day so I could drive it home. But when I started the car with the new battery in it, it kept wanting to stall. I had to keep my foot on the throttle for 2-3 minutes before it finally settled into an acceptable idle, and drove home with the dead alternator still in it.
I had the alternator rebuilt, but when I put that one back in, it still didn't charge the battery. It turned out the cable from the positive battery post to the alternatour output post melted or corroded through, so I fixed that. But even then, the alternator still didn't charge the battery. I believe the damaged cable was the original problem, which fried my alternator twice.
Yesterday, I put in a brand new alternator, and the car finally charges again. Yay! BUT, the car still runs like crap and it keeps wanting to stall, unless you feather the throttle and give it CPR for 2-3 minutes.
My car has now been sitting in my garage for 2 months, and I missed an entire summer of cruising, which was the reason for buying the car in the first place.
It is my understanding that incorrect alternator output voltage can cause a rough idle and stalling, so I was pretty confident that finally fixing the alternator problem would also solve my stalling problem. Especially giving that these 2 problems occured at the same moment. But I was wrong.
Additional info
- Full service manual for reference: Repair and Diagnosis — 1986 Chevrolet Caprice V8-305 5.0L Service Manual | Operation CHARM
- Electric choke seems to open like it should.
- Choke pull-off holds vacuum - I feel like it cracks open the choke a bit too much on initial startup, but I never touched the adjustment screw, so I don't think this is what causes my problem.
- I cleaned the EGR valve. It also holds vacuum.
- Throttle position sensor is within spec.
- No check engine lights. I tried reading codes, it only reads code 12, but that was after the engine only ran a few seconds and stalled. Not sure if it should run it longer in order to retrieve the codes.
- When I jump the diagnostic connector, there is a very fast clicking sound - almost buzzing - coming from a white connector on the passenger side of the distributor. I've been told that the diagnostic mode will typically power some relays, but I haven't heard this sound in any of the OBD1 videos I see on YouTube. To be clear: It is not the mixture control solenoid which normally clicks with key on and engine off. I know that sound.
- Starting procedure I use is exactly what I used before the issues arose: Depress throttle once to set choke closed, turn key and voilà. Car cranks with plenty of speed / power.
- Car is usually harder to start after it stalls the first time. Simply turning the key usually isn't enough at that point, and I have to depress the throttle as I crank for it to start.
- The first few seconds after it cranks, the engine usually runs fine. It will, however, always stall quickly if I don't do anything, but it will stall instantly when I give a bit of throttle. RPM's go up and then seem to just drop through the floor and stall the engine.
- If I am able to get it to idle after a few minutes, it sometimes also seems to increase RPM's by itself. I usually shut it off quickly after that as I am afraid it will get worse.
- Before the alternator issue, I remember a few times where the aftermarket radio would continue to be on after taking the key out. I have not used the radio since then but I remember being surprised.
Any input is much appreciated. I am at a bit of a dead end here and need some fresh perspectives. Thank you!
10-30-2023, 05:34 PM
#4
Member
Join Date: Jan 2003
Location: Long Island N.Y
Posts: 380
Received 12 Likes
on
12 Posts
Car: 1988 Pontiac GTA
Engine: 5.7 l98
Transmission: 700r4
Axle/Gears: BW 9bolt with torsen carrier
Re: Car stalls when cold after alternator problem - please help
Driving the car multiple times with a non working Alternator will kill a new battery.
Thread
Thread Starter
Forum
Replies
Last Post