No sparkplug firing while starter turns engine over on low battery

[CosmickGold]

When my engine battery is low, the starter turning the engine over pulls the voltage down below the point where the sparkplugs can fire.
Is there a way to add a small battery for the ignition system to power it separately while the main battery is overloaded by cranking the engine?

 

[Malamute]

On many newer vehicles, if the voltage isnt at a certain level, they simply wont fire, unlike older points type systems. generally the only thing to do is jump it or charge it.

You can borrow a battery thats charged to jump yours, or buy one, whatever. If adding one, be sure you are hooking them up in parallel (+ to +, - to -) rather then in series so you maintain 12 v and not make it 24 v.

Some people add another battery under the hood for extra cranking power.

 

[bullfrog]

Another issue is that if your vehicle has fuel injection the fuel injectors usually won't work below 11.5 volts.

 

[abnorm]

Is this new since you added the cutoff ?

 

[CosmickGold]

Is this new since you added the cutoff ?

Nope. On the contrary, I added the cutoff to try to keep the battery up so that the low-voltage problem will stop happening.

 

[abnorm]

............a little TOO late !...................just get a new battery

(My concern with the switch was that the "Bolt" makes so little contact....MORE is Better)

 

[user 16179]

Perhaps a starter draw test is in order. Kinda step #1. A starter with a problem with draw more current. It's a simple test probably done free at "chain" auto parts stores that test batteries and charging systems to determine what you need. No sense guessing and throwing unnecessary parts at it.

 

[Dennys Adventures]

my 1996 Subaru will not start with a low battery. I have used the what i call the house battery to jump start it. are you sure you do not have a battery drain problem. if you do you need to repair that problem. I agree with wrongway2 have a auto parts shop check the starting and battery systems out.

 

[kklowell]

If the battery is going low while disconnected, replace the battery.

 

[jonyjoe303]

If the engine is cranking it should start. Does it turn over very slowly? I had similar problems with my van, where after sitting over a weekend it crank very slowly but it would start every time barely.
One thing I found was one of the side terminals was loose, the bolt was too short, after replacing the terminal it did fixed it but every once in a while I still got slow cranks because I didnt drive often enough to keep the start battery fully charged and the 14.4 volts wasn't enough for my agm.
I built a 2 amp charger (using a boost buck converter) and every day I top off the battery before I start it. I'm using a 27ah agm (10 year old battery) as a start battery it requires 14.7 volts to fully charge, my charger is set to 14.7 volts. The best part I charge it from the cigarette receptacle. No need to run wires all over the place. To top it off, I usually turn the charger on 5 minutes before I get ready to start the engine, that quickly tops the battery off. In the 2 years I been doing this, haven't had any more dead batteries or slow cranks.
I used a boost buck converter with an LED because I like to see the status of the battery as its charging. But any 2 amp or 4 amp charger will work as long as it puts out 14.4 volts for regular lead acid. 2 amps is all I ever needed, its rare it takes more than 5 minutes to reach 14.7 volts.
The input goes to the house battery, the output goes to the cigarette receptacle on the console.

 

[CosmickGold]

Another issue is that if your vehicle has fuel injection the fuel injectors usually won't work below 11.5 volts.

I didn't know that. So it might be that the spark is just fine and it's the fuel that isn't getting there.
Same solution needed!

 

[CosmickGold]

.

 

[CosmickGold]

....

....

....

You guys are coming up with some truly brilliant answers. Wow!

 

[tzagi]

A battery for the ignition is not possible, and even if it was, it wouldn't help, when the ecu reads less then 12v at cranking it will not fire the plugs or the injectors, the solution is not to have a low battery, furthermore, everytime you bring the battery to a state under 12 volts you shorten its life by 10%

 

[CosmickGold]

A battery for the ignition is not possible, and even if it was, it wouldn't help, when the ecu reads less then 12v at cranking it will not fire the plugs or the injectors, the solution is not to have a low battery, furthermore, everytime you bring the battery to a state under 12 volts you shorten its life by 10%

Thanks, tzagi. I didn't know separating the cranking battery wasn't possible; so that's why I can't find others who have done it. I probably need a new battery -- again -- got one two years ago, but have run it down to nothing more than once. (Duh!) But now I have a battery disconnect switch, hoping to never run it down again.

 

[tzagi]

For your house battery you can't beat the group 27 rv/marine, $69 at walmart, Keep it isolated when parked.Starting batteries do not like to be discharged and charged on a normal basis hence the short life span, rv batteries are not bothered by it as much...as long as you don't bring them under 12v, alarms/automatic disconnects are available to solve that issue.

 

[John in Montreal]

I didn't know that. So it might be that the spark is just fine and it's the fuel that isn't getting there.
Same solution needed!

Have you done a spark test?

In my experience an "engine cranks, no start" usually means the battery is ok and either the engine's not getting fuel or there's a problem with the ignition system.

If you're not getting spark I'd check the ignition control module. And while you're poking around in there get some sandpaper and some little wire brushes and clean every electrical connection you can get to. Battery posts, starter cables, plug boots and check all the connections in your ignition system are tight.

 

[CosmickGold]

Have you done a spark test?
In my experience an "engine cranks, no start" usually means the battery is ok and either the engine's not getting fuel or there's a problem with the ignition system.

I'm sure you are correct in many if not most cases, and gave good advice.

But in my case, I had this problem two years ago of cranking and cranking and no start. I was told "if you've got enough power to crank the engine, it's not the battery because that's enough power for a spark and gas. However, when I fully charged the battery, it started right up! So I bought a new battery which solved the problem that year. It was the most expensive battery -- about $300 -- but I think I have abused it so much it's now mosying slowly toward "The Elephant Grave Yard". So this time I'll take tzagi's advice and just get the $69 battery; he said it can't be beat.

 

[tzagi]

* Can't be beat on capacity vs price, as you are in Arlington...check around Jefferson BL in GP, Years ago there was a guy there selling reconditioned batteries for like $30, 6 month warranty but that was like...over 10 years ago.

 

[John in Montreal]

I'm sure you are correct in many if not most cases, and gave good advice.

But in my case, I had this problem two years ago of cranking and cranking and no start. I was told "if you've got enough power to crank the engine, it's not the battery because that's enough power for a spark and gas. However, when I fully charged the battery, it started right up! So I bought a new battery which solved the problem that year. It was the most expensive battery -- about $300 -- but I think I have abused it so much it's now mosying slowly toward "The Elephant Grave Yard". So this time I'll take tzagi's advice and just get the $69 battery; he said it can't be beat.

Bad ground strap could be why the battery isn't charging.