car wont crank unless jumped, battery dying, low idling ( sometimes at 100 rpms) and then stalling, driving at 50mph and throttling and drops to 0mph

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Update: took off one of the spark plugs, and they were all black at the tip. replaced them all, and still no start. tried starting the car but no luck, took off the fuel line at the filter and no fuel comes out when cranking. I then put the fuel line back on and tried to start it but instead of fluttering the gas, I floored it... and IT STARTED. it idled at 650 for a bit then slowly went down, alternator was reading 11.93 volts and now is reading 10.96. car idles at correct rpms for a minute then slowly goes down as the battery and alternator volts go down.

what I did
-took out the whole alarm system ( I think)
-replaced all the spark plugs
-put correct ampage fuses in the small efi fuse and charge fuse
-had battery checked at auto store but I knew it would score low because I had been trying to start truck with it.

wondering what the next step is, could it be the connected at the alternator or the alternator itself?
or is it just a dirty or corroded point or wire
 
cruisingalong45 said:
Update: took off one of the spark plugs, and they were all black at the tip. replaced them all, and still no start. tried starting the car but no luck, took off the fuel line at the filter and no fuel comes out when cranking. I then put the fuel line back on and tried to start it but instead of fluttering the gas, I floored it... and IT STARTED. it idled at 650 for a bit then slowly went down, alternator was reading 11.93 volts and now is reading 10.96. car idles at correct rpms for a minute then slowly goes down as the battery and alternator volts go down.

what I did
-took out the whole alarm system ( I think)
-replaced all the spark plugs
-put correct ampage fuses in the small efi fuse and charge fuse
-had battery checked at auto store but I knew it would score low because I had been trying to start truck with it.

wondering what the next step is, could it be the connected at the alternator or the alternator itself?
or is it just a dirty or corroded point or wire
Click to expand...
Have you replaced the battery yet?
 
Old Nick said:
Have you replaced the battery yet?
Click to expand...
If you’re seeing your voltage drop, your alternator is almost certainly toast, as is your battery. Nothing wrong with the things you’ve done, but they are dancing around the issue. I’ll emend my post above to say that you’re likely in need of a new alternator and a new battery. BUT, start with the battery and quit throwing money at your rig until you’ve addressed those two things.
 
Old Nick said:
If you’re seeing your voltage drop, your alternator is almost certainly toast, as is your battery. Nothing wrong with the things you’ve done, but they are dancing around the issue. I’ll emend my post above to say that you’re likely in need of a new alternator and a new battery. BUT, start with the battery and quit throwing money at your rig until you’ve addressed those two things
Click to expand...
but won't I just fry the new battery if the altnernator is bad?
 
cruisingalong45 said:
but won't I just fry the new battery if the altnernator is bad?
Click to expand...

If the alternator isn't charging the battery properly, the battery won't get a full charge, meaning it will struggle to provide enough power for the starter, electronics etc.

The alternator should be putting out a minimum 13.5 volts, or slightly higher.
A fully charged battery should read about 12.5-12.7volts.
If the alternator output is low, eventually the battery will die, but it won't happen immediately.

Some of the car's electrical system will tolerate low voltage, some things will not.
Things like lights will just be a little dim if volts are low.
Some electronic components ( like inside the ECUs) will only work properly if voltage is within a fairly small range.
If you're seeing 11.5 volts, I would say that's logs enough that things aren't going to function properly
 
Please read post #2.
Please read post #28.

Please read post #2.
Please read post #28.

Please read post #2.
Please read post #28.

Please read post #2.
Please read post #28.

Please read post #2.
Please read post #28.

Please read post #2.
Please read post #28.
 
COS80 said:
What's your battery's V with the engine off, after sitting for a while?
Click to expand...
sitting at 12.12 with the battery out of the car right now. for jonhelds sake and mine I put my moms battery in the my truck and it started up and idles correct then goes down, the voltage was around 12.23 with the car running and the alternator was not charging the battery. so either connection or the alternator (I will be buying new battery when my check comes in)
 
cruisingalong45 said:
sitting at 12.12 with the battery out of the car right now. for jonhelds sake and mine I put my moms battery in the my truck and it started up and idles correct then goes down, the voltage was around 12.23 with the car running and the alternator was not charging the battery. so either connection or the alternator (I will be buying new battery when my check comes in)
Click to expand...
Seems like the alternator is the main culprit, then. I'd start there. Put that battery on a charger until you have the alternator replaced, so it's fully charged.
 
cruisingalong45 said:
sitting at 12.12 with the battery out of the car right now. for jonhelds sake and mine I put my moms battery in the my truck and it started up and idles correct then goes down, the voltage was around 12.23 with the car running and the alternator was not charging the battery. so either connection or the alternator (I will be buying new battery when my check comes in)
Click to expand...
What car does your mom have?
On the label on your mum's battery, it should have a few different ratings.

One will be CCA. What is this number?
It should also show an AH or A/Hr number too.

CCA is cold cranking amps. This is what gets the car started.
AH is amp hours. This it's good long the battery can supply a certain amount of power before it drops too low in voltage.

If your mom has a small car, the battery might be just enough to start the landcruiser, then be low enough it's struggling to keep feeding the engine power when the alternator isn't also providing power.

When everything is working properly, the battery starts the car, then the alternator provides power to keep it running. The battery is only a reserve of power for times the alternator isn't producing enough power. A properly functioning alternator in a modern vehicle (newer than about the 1960s) should make enough power at idle to run the engine.
If the alternator isn't producing enough power to keep the engine running, the battery will drain down fast.

The alternator needs to put out 13.5 comes so it exceeds the 12.5 volt charge in the battery.
If the alternator is reading less than 12 volts, it doesn't just charge a little bit, it charges not at all.
A weak alternator trying to charge a good battery is like you having a pissing contest with a 2" fire hose.
 
mudgudgeon said:
What car does your mom have?
On the label on your mum's battery, it should have a few different ratings.

One will be CCA. What is this number?
It should also show an AH or A/Hr number too.

CCA is cold cranking amps. This is what gets the car started.
AH is amp hours. This it's good long the battery can supply a certain amount of power before it drops too low in voltage.

If your mom has a small car, the battery might be just enough to start the landcruiser, then be low enough it's struggling to keep feeding the engine power when the alternator isn't also providing power.

When everything is working properly, the battery starts the car, then the alternator provides power to keep it running. The battery is only a reserve of power for times the alternator isn't producing enough power. A properly functioning alternator in a modern vehicle (newer than about the 1960s) should make enough power at idle to run the engine.
If the alternator isn't producing enough power to keep the engine running, the battery will drain down fast.

The alternator needs to put out 13.5 comes so it exceeds the 12.5 volt charge in the battery.
If the alternator is reading less than 12 volts, it doesn't just charge a little bit, it charges not at all.
A weak alternator trying to charge a good battery is like you having a pissing contest with a 2" fire hose.
Click to expand...
also side note, I did take the battery out after got my rig started and it died so... alternator no work for sure.

her car info:
Honda Odyssey
650cca
800 ca
not seeing a reading for ah
its a 24f battery
 
First things first if your battery is healthy you can drive for quite the distance with no alternator output my record is 58miles and I really waited to tun on the lights till the last second of visibility and ran no music or heater.
1- get a new battery
2- get a DMM and test voltage at batt
3- if less than 13.9-14.5 at battery
4- check power output at alternator main wire Is it less or more than 13.9-14.5
5- steal underpants
6- profit.
 
cruisingalong45 said:
sitting at 12.12 with the battery out of the car right now. for jonhelds sake and mine I put my moms battery in the my truck and it started up and idles correct then goes down, the voltage was around 12.23 with the car running and the alternator was not charging the battery. so either connection or the alternator (I will be buying new battery when my check comes in)
Click to expand...
You don't seem to be following along with the rest of the class.
ANYTHING you do besides getting the charging system (BATTERY; FUSIBLE LINKS; ALTERNATOR) replaced or tested is a waste of your time.

This vehicle WILL NOT RUN without a proper charging system.
This vehicle WILL NOT RUN without a proper charging system.
This vehicle WILL NOT RUN without a proper charging system.

So I'll say it one more time for those in the back of the room.

IN THE FOLLOWING ORDER:
1. REPLACE THE BATTERY
2. REPLACE THE SET OF 3 FUSIBLE LINKS
3. HAVE YOUR ALTERNATOR TESTED/REPLACED

NOTHING ELSE YOU DO WILL MAKE ANY DIFFERENCE
 
The day has Come! I replaced my alternator, fusible links, and battery, all seems to be working. volts are reading good 14.2-6. but may have a new problem... when I got the truck I heard a small air release from radiator and I popped the hood today after driving it around 7 miles and there was a small few inch long crack along the plastic top tank of radiator. not shooting out, just seeping.
 
cruisingalong45 said:
The day has Come! I replaced my alternator, fusible links, and battery, all seems to be working. volts are reading good 14.2-6. but may have a new problem... when I got the truck I heard a small air release from radiator and I popped the hood today after driving it around 7 miles and there was a small few inch long crack along the plastic top tank of radiator. not shooting out, just seeping. also the car still is idling down at stops
Click to expand...
 
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