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Car sometimes won't start / sometimes just dies during driving
1972 Oldsmobile Cutlass Supreme 350sbo/th350
Have not been driving it for a couple months.
Yesterday i did and i BARELY made it back home.
Drove to a restaurant and after coming back the car did not start. NOTHING. thought the starter went bad.
But turns out after some troubleshooting (checking battery terminals etc.) and finding basically nothing
it came back to live / could start it again.
On the drive back home it DIED one time during driving for no reason. Again nothing when trying to restart for about 1 minute
but after that it worked again. (Without me doing anything)
Two things i observed:
1. The starter sounds VERY weak (It's a rebuilt ACDELCO starter because the original one went bad last year)
2. When the car does not start there are also no interior lights, the exterior/headlights work fine in this situation though
Could it be a bad starter? Is the power for the ignition/interior lights routet/wired through the starter?
Or what could it be?
Hope this is a known problem because i have no idea where to start, especially since
the problem is coming and going and it's running fine most of the time.
I also noticed the car seems to be down on power somewhat.
Not really noticeably driving around town but when i floor it you definitely notice. So maybe weak spark because
of to much resistance? (Since the starter is also weak)
#1 What is the current voltage in the battery? It should be >12.6V. Measure the battery voltage without the car running - either with the battery attached or without the battery attached. Tell us what the voltage is of the battery.
#2 Can you start the car? Jump start or whatever? If you can start the car measure the battery voltage with the car running. You should see >13.9V and nominally 14.3V. Tell us what the voltage is of the battery with the car running so we can sense if the alternator is doing its job.
The problem is not persistent.
SOMETIMES i can start it, sometimes i can't.
SOMETIMES it dies during driving, most of the time it does not.
Yesterday this stuff happened for the first time.
Today without doing anything the car started & ran just fine.
But the starter sounds always weak. That is consistent.
Pretty much since it got installed last year after the original one went bad.
I would be VERY surprised if the battery or alternator could cause those intermediate issues.
Because if the alternator was broken the car would not start at all without recharging the battery.
If the battery was dead the car would not start without a new battery.
And yes the battery tests good.
Your call if you don't want to provide the voltage numbers.
Take off the battery ground cables, clean the terminal ends and the attachment points. Cut back ~4"-5" on the battery cables - notice any blue/green oxidation?
#1 What is the current voltage in the battery? It should be >12.6V. Measure the battery voltage without the car running - either with the battery attached or without the battery attached. Tell us what the voltage is of the battery.
#2 Can you start the car? Jump start or whatever? If you can start the car measure the battery voltage with the car running. You should see >13.9V and nominally 14.3V. Tell us what the voltage is of the battery with the car running so we can sense if the alternator is doing its job.
^^^THIS^^^
You mentioned the battery tested good. Do you use your multimeter to test the voltage at rest and when idling? If not, you can go to your local auto parts store and they can test the battery and starter. If the car dies at the auto parts store they'll have a jump starter to get you back on the road.
Your call if you don't want to provide the voltage numbers.
Take off the battery ground cables, clean the terminal ends and the attachment points. Cut back ~4"-5" on the battery cables - notice any blue/green oxidation?
I looked at this stuff yesterday i do not recall the exact number. The terminals look fine, i replaced them last year because one of the old ones broke in half.
But i will test the battery and alternator such as look at the cables one more time asap. Right now i can't because the car is not stored at my house.
But i'm pretty sure the problem is something else / not that simple.
- Sometimes the starter works, sometimes it does not
- When the starter does NOT work, the interior lights also do not work
- When the starter and interior lights do NOT work, the exterior/headlights DO work
- Without doing anything the interior lights and starter will come back to live after some time
This really can't be pinned on to the battery or alternator, right?
It pretty much has to be a wiring issue, right?
But again i doubt its the battery terminals. I already checked them.
I will check the battery terminals/wires, battery and alternator again asap.
But since i don't think they are the problem:
What else could it be?
Could it be a bad starter? Is the power for the ignition/interior lights routet/wired through the starter?
If the engine dies while driving that means the ignition system is deprived of electrical power. In other words you having wiring issues.
You will need to grab a test light, start at the battery, disconnecting and cleanng terminals as you work your way toward the coil then the starter. Ground wires definetly need to be addressed in the same manner.--disconnect, clean, reconnect. The alternator needs to be verifed, as does the ignition switch too.
I had a few of these problems, maybe all of them?
Lots of electrical trouble shooting with now real solve for awhile.
Then I noticed the front harness connection/junction looked askew…
Turns out the big screw that hold the front to the back through the firewall was loose and about to come apart.
One big screwdriver turn fixed averything.
Then I noticed the front harness connection/junction looked askew…Turns out the big screw that hold the front to the back through the firewall was loose and about to come apart. One big screwdriver turn fixed averything.
Peter - Are you referring to the ground strap from the back of the engine to the firewall?
No need to be concerned about the ground strap at the back of your engine if you have parts store cheapie battery terminals. You said in an earlier post that you replaced the battery terminals because the OE ones were worn and damaged. Chances are if you cut the insulation back like Norm mentioned you'd see green oxidation and corrosion. As you mentioned, a poor ground from your battery can cause all your symptoms. Just sayin'...
It's called the "ground strap" as identified in the image I posted (if that's what Peter is referring to).
Thanks.
Originally Posted by Olds64
No need to be concerned about the ground strap at the back of your engine if you have parts store cheapie battery terminals. You said in an earlier post that you replaced the battery terminals because the OE ones were worn and damaged. Chances are if you cut the insulation back like Norm mentioned you'd see green oxidation and corrosion. As you mentioned, a poor ground from your battery can cause all your symptoms. Just sayin'...
Do you know where i can buy original/quality battery terminals and cables?
I was not able to find any.
-----
I will try to look at all things mentioned tomorrow.
Just an example of what can occur in areas you cannot witness. This is the ground cable from my Indian motorcycle - starter began failing intermittently, bike would shut off while riding on several occasions. It happens more often than you might think on all types of equipment. It's worth cutting back the ends of the cables. Electrical resistance will increase significantly when there is no direct path to ground.
Yes, I’m talking about the screw/bolt that holds the fuse block to the engine bulk head connector.
(sorry if I wasn’t clear)
Sometimes they’d separate and I’d lose my lights, sometimes the car would die, sometimes it wouldn’t even click.
Last edited by Rallye469; Jul 9, 2023 at 08:11 PM.
If you have a voltmeter and a freind to help do this. You might have to purchase some longer probe wires with alligator clips on the ends.
Disconnect both battery terminals
One of you hold voltmeter clips (better than just using the pointy probes) on either end of the negative battery cable as near as possible to the ends and the other flex/work the cable, specially near the ends, the measurement should be consistently close to zero ohms.
Do the same for the positive cable going to the relay block on the fender (I think that is where it is on your car).
If either is sporadic or fluctuates then you have a bad cable as Norm showed with his motorcycle in pictures above, replace it.
OR just replace them both...
Lots of good advise given here. Take off EVERY connection point & clean them well. Trim back the battery cables where they meet those terminals. Be sure it's a clean connection. Then check them once in a while. They work loose & corrode. Ask me how I know.
For those who may not know it, Electrons flow along the OUTSIDE of copper wire, not "through" copper wire. That is why oxidation is such a bear, as Norm showed in Post # 22, above.
I just came back from diagnosing, test driving and probably fixing the car.
Turns out the battery terminals have really been somewhat loose.
(When this originally happend i had no tools with me. With my eyes and hands they appeared to be firm, but they obviously weren't.)
To defend myself:
There is an additional wire going off from the negative battery terminal which goes to the headlights.
So it seems like the headlights have an additional ground and because of that have not been affected like the rest of the car.
I did not notice that when i first had those issues on the road. That's why i misdiagnosed the problem to be something more severe than just a loose/faulty battery cable.
Well that is IF the problem doesn't come back. Only a few more drives will tell.
I borrowed a multimeter from my dad.
Engine off: 12.6V on the battery posts
Engine running @ idle (directly after starting): 13.3V on the battery posts
Seems to be somewhat on the low side but i don't know if i can trust the multimeter or maybe i set it up wrong. (I do not think that i have set it up wrong, though)
At this point everything works fine.
Car starts right up/starter isn't weak anymore. It's also definitely regained some horses and also runs cooler compared to last time. So ignition seems to get enough juice again aswell.
There is an additional wire going off from the negative battery terminal which goes to the headlights.
So it seems like the headlights have an additional ground and because of that have not been affected like the rest of the car.
If there is an additional wire from the negative battery terminal to headlights it was not installed OEM from the factory. There is only one additional wire from the negative battery terminal which attaches to the side baffle (chassis ground wire) outboard of the radiator. Someone else installed that wire & I'd be suspicious as to why they installed an additional ground to the headlights.
To the OP, if you can't remember when you last cleaned the ground wires in the engine bay, the wires at the junction block, or the coil + and - wire then it's time to do it. Plus if you are running points and condenser in the dizzy, it's probably pass due to have those items changed as well.
For those who may not know it, Electrons flow along the OUTSIDE of copper wire, not "through" copper wire. That is why oxidation is such a bear, as Norm showed in Post # 22, above.
And for what it's worth, our body's nerve impluses work in a similar manner, flowing along and not through neuronal receptors.
So it has been awhile since I have dealt with this issue.
Three things.
1. The interior light issue puzzles me. Sounds ground related but not an issue not related to your main problem.
2. Where was your starter rebuilt? Please anyone here more knowledgeable than me correct me if I am wrong. From what I remember a starter that creates "drag" as wires brushes etc are misaligned can basically ground out the entire system.
3. The car dieing as you are driving it. At first I thought fuel but your electrical issues say to me that something is grounding out causing these issues. Starters rebuilt incorrectly can cause this. Just my opinion but I would love to hear feedback. A starter grounding out internally could cause this. Interior lights? Possibly but...
Last edited by no1oldsfan; Jul 10, 2023 at 06:12 PM.
I have run my car with no battery, just the alternator and all was fine. I have also run it with no alternator, just the battery, and it ran fine until the battery was discharged to around 7 Volts then the engine died.
The OP has at least one electrical wiring issue - there should exist no ground wire from the battery negative (-) terminal to the headlamps on this car. Whatever the reason for that ground wire to the headlamps - I'm sure it warrants additional review of wiring.
Today i've been driving around for a couple hours.
I made 5 stops where i shut the car off for 5-15 minutes each then turned it back on.
The car did not die or anything so it almost seems like it really was just a bad ground due to a loose battery cable.
BUT the starter is/sounds weak again.
Well since that starter is weak since it got installed last year, i almost suspect that's a seperate problem / has been poorly rebuilt. (It's a rebuilt ACDelco starter)
So my plan is to see if i can get my hands on a correct NOS starter and see if that fixes this problem once and for all. I have a feeling it will.
Interestingly the starter isn't always weak, though.
Originally Posted by Vintage Chief
If there is an additional wire from the negative battery terminal to headlights it was not installed OEM from the factory. There is only one additional wire from the negative battery terminal which attaches to the side baffle (chassis ground wire) outboard of the radiator. Someone else installed that wire & I'd be suspicious as to why they installed an additional ground to the headlights.
Well i double checked and this wire you say should not exist, well it does exist.
As to why it's there your guess is pretty much as good as mine. Here's my guess:
I live in germany and the previous owner imported and restored (not perfect but decent) the car decades ago.
In order to drive these cars legally on the street you have to do some "euro conversion" and i know that involves changes to the lighting. Maybe this extra ground is required here in germany by law. I don't know it's just my best guess.
Edit:
If someone has (and wants to sell) a correct, working NOS starter for a 1972 Oldsmobile Cutlass Supreme with the 350 4bbl engine and TH350 transmission please let me know. I would be highly interested in buying it.
Edit:
That said i've read in the past that the GM/ACDelco starters have problems with high heat and humidity.
Currently it's pretty hot and humid where i live. ^^
Last edited by Michael_; Jul 16, 2023 at 03:39 PM.
