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Trying to find the electrical draw that drains the battery...

Not so sure on the starter draining the battery but a bad diode in the alternator can drain the battery. The bad diode can cause the circuit to charge even with the engine off, draining the battery.
 
Can an alternator be bad if it is charging correctly ?
YES

Can a starter draw so much power that it drains a battery just by sitting?
Normally no, starters don't draw any power unless it's cranking... There is no power passing through the wire that triggers the solenoid... But there is a big battery wire supplying power that in theory could drain the battery, But I've never seen one do it...
 
Trunk mount Battery? Have you checked your cables?
Yeah, the battery is in the trunk. The positive cable runs to a Ford solenoid then across the axle hump and to the left side. Inside, it runs along the left rocker inside and up through the firewall to the starter. It isn't exposed to the elements except in the engine bay.
I did check the voltage reading at the starter relay and the number is almost the same as the battery. It is hard to test the alternator stud for voltage with the car running since it is so close to # 2 header tube.
 
This wasn't the problem.
The problem persists. With a battery over 12.6 volts, the car spins over. Below 12.4, it drags like there is 20 to 1 compression!
I put the starter in in 2008. When the engine is cold, the starter doesn't spin that fast. When the engine is warm, it seems to spin faster. When the engine has been run awhile, it turns over slower but still enough to start. It never seems to crank over fast like I have heard other big block cars with the Denso mini starter. I am wondering if this starter is a contributing factor.
Last time I was going around with this problem, I found the map light to be A problem. It obviously is not THE problem.
I did not disconnect the alternator. It is charging. The voltage at the relay and battery is higher with the engine running. Can an alternator be bad if it is charging correctly ? Can a starter draw so much power that it drains a battery just by sitting? That makes no sense to me but who the heck knows. I have another new mini starter here to try. It requires unbolting and moving the header so I'd rather save that task for later if I can.
I am going back to square one tomorrow. Pulling the alternator wire, fuses and who knows what else. I have been intending on correcting a few errors with the wiring anyway. When I changed to these aftermarket gauges, some of the lighting wires got grouped together and connected to the wrong power feed. The trunk light only comes on with the key ON. The radio won't hold a memory.
Lots to do !
Maybe last time I quit looking too early and didn't
Do not discount the starter motor.
I am going to relate a story from a recent problem with a Ferd car that we have. The engine is a 250cui straight 6, and EFI...blah blah. Anyway...I had been getting a load of fault codes up for a while now. One day not long ago, I drove for about 40 miles, pulled up at my electrical supply shop, and tried to restart after about 10 minutes. The engine would not even turn over. Immediately I suspected the battery, and sure enough - it was hot to the touch on both posts - Pos &Neg. So, we tried jump starting with another running car...no luck. All the engine would do was 'grunt' and not even look like turning over.
***Worth noting that this is quite normal - if the non-running car battery is dead, most likely another running car & battery will not help much.

I went over to the local SuperCreep Auto store and bought a new battery - big spendy (mucho denaro) ....installed, and still no go.

Called a local Tow Truck to drag the POS home for inspection. He pulls up, drops his ramps, and e are ready to winch the car on board the flat deck. Just for S&G the Towie says "Give me the keys" ....he jumps in and tried 3 times to start the car - third time it roared into life.

Luckily for me, I know the guy, so he said it was my lucky day, and no charge for stopping by. He wouldn't even take some beer money when offered. I get home and start trying to figure this out. The very next day, when the car was cold, it started fine...a little sluggish winding over....but it started.

I went out to see my buddy Cliff, and we discussed the situation over coffee.....decided the best course of action was to check the codes. The guy in the shop next door had the comprehensive Scanner tool...so he found dozens of codes. The crux was that it looked like the voltage was dipping just a little too much - and since the Ferd model we have is very sensitive to voltage variations, the on-board computer was throwing a hissy-fit every time we started it.

The decision was made to replace the starter motor - a bit radical at this stage, but other ideas didn't seem to stack up as much. I had remembered that the car had wound over a bit sluggish for some time. The original battery was put on a super duper battery charger, and showed up as being as good as the day it was installed....nothing wrong with it. After we installed the new starter motor, the car absolutely roared into life, with much more vigour than I could remember ...ever. At this point we decided to examine the old starter (it had been only in the car for about 3 years) - we found a massive build-up of carbon dust, and the commutator looked a bit heated. It would appear that the excessive carbon build-up was causing enough of an electrical short to pull down the battery voltage during cranking. This was what appeared to have been triggering the codes.

Since then, the codes have been cleared, touchwood none have returned, and the car can be cranked & started after 3 weeks of sitting idle. Before this, if it was left for anything more than one week, the starter motor was very sluggish.

So, please do not rule out your starter motor Greg......you never know.

:xscuseless:

Here's a picture of the car....photo courtesy of the Speed Infringement Division of the NZ Police. :D

upload_2020-6-14_18-39-29.png
 
Thank you.
I have heard other Mopars with high performance engines and they seem to crank over much faster than I do. It has almost always been this way with this car. When the engine has been warmed up, it fires up quickly...The starter spins pretty fast and the engine fires up right away. I run a 10w40 oil so it isn't as if I'm trying to crank over a cold engine on 60 weight Harley Davidson oil!
 
Thank you.
I have heard other Mopars with high performance engines and they seem to crank over much faster than I do. It has almost always been this way with this car. When the engine has been warmed up, it fires up quickly...The starter spins pretty fast and the engine fires up right away. I run a 10w40 oil so it isn't as if I'm trying to crank over a cold engine on 60 weight Harley Davidson oil!
Are you running a factory style gear-reduction starter motor? This will make the car sound more sluggish than others if they are running a direct-drive (1:1 ratio) starter motor. And the fact that you have the battery in the trunk, probably accounts for at least 1 Volt of loss at the starter under cranking conditions....and remember you are lucky to see 9 Volts at the starter under cranking conditions.

I ran a direct drive starter motor in my GTX, and it was way easier to start than with the original style. Most people refer to them as a Mini-starter. They can make the firing of an engine so much quicker, and for less harm to the condition of the battery.

There is nothing worse than the sound of a factory starter on a dying battery.
 
Yeah, the battery is in the trunk. The positive cable runs to a Ford solenoid then across the axle hump and to the left side. Inside, it runs along the left rocker inside and up through the firewall to the starter. It isn't exposed to the elements except in the engine bay.
I did check the voltage reading at the starter relay and the number is almost the same as the battery. It is hard to test the alternator stud for voltage with the car running since it is so close to # 2 header tube.
This is interesting! My 94 GT Mustang does the same thing. As I was reading previous posts I said, "it sounds like my Mustang problem" unfortunately I have not been able to fix that either. But I would consider the Ford solenoid??
 
Yeah, the battery is in the trunk. The positive cable runs to a Ford solenoid then across the axle hump and to the left side. Inside, it runs along the left rocker inside and up through the firewall to the starter. It isn't exposed to the elements except in the engine bay.
I did check the voltage reading at the starter relay and the number is almost the same as the battery. It is hard to test the alternator stud for voltage with the car running since it is so close to # 2 header tube.

Do a voltage drop from the battery to the to the starter for both power and ground
 
Good idea.
I just went out to check on it. To charge this AGM battery, I have to use a conventional battery as a go-between.
First, I disconnected the negative cables from the battery and bridged them to the post with the test light. There is no spark and the bulb does not light up.
I connected the cables and checked voltage. Sometimes these AGMs charge to 13 volts or slightly over, sometimes the charging unit shuts off in the 12.6 range. This time it was at 12.5. The car would barely turn over. I used jumper cables to the other battery and it spun over fine, actually faster than usual. Is it the AGM battery to blame?
No. I disconnected the cables from the AGM and connected jumper cables directly from the good battery. The starter spun over just as slow as it did with the AGM battery alone.
In short, neither battery on its own can adequately spin the engine over despite having adequate voltage. The batteries together work just fine. I do suspect the starter now or at least the connections at the starter.
 
I had a '63 Pontiac Grand Prix (389) that would overheat in traffic and burn up starters right and left. Coincidently, when I replaced the automatic transmission the overheating/starter problems went away. Need to think outside the box sometimes.

Pontiac Grand Prix.jpg
 
Throw a normal short cable on the starter & temporarily move the battery up front, if it cranks normally look are your cables front to back, if it doesn't focus on the starter...
 
I read the whole post and I didn't see anything about what gauge wire you are running from the trunk mounted battery.
On the dirt track cars we run #4 fine strand and run a short ground to the frame in the back near the battery and then
another short ground from the frame to the block.
 
Good idea.
I just went out to check on it. To charge this AGM battery, I have to use a conventional battery as a go-between.
First, I disconnected the negative cables from the battery and bridged them to the post with the test light. There is no spark and the bulb does not light up.
I connected the cables and checked voltage. Sometimes these AGMs charge to 13 volts or slightly over, sometimes the charging unit shuts off in the 12.6 range. This time it was at 12.5. The car would barely turn over. I used jumper cables to the other battery and it spun over fine, actually faster than usual. Is it the AGM battery to blame?
No. I disconnected the cables from the AGM and connected jumper cables directly from the good battery. The starter spun over just as slow as it did with the AGM battery alone.
In short, neither battery on its own can adequately spin the engine over despite having adequate voltage. The batteries together work just fine. I do suspect the starter now or at least the connections at the starter.

Out of curiosity, what size is the positive cable that runs ftom the trunk mounted battery to the engine compartment connection point? The cable size should be expressed as a gauge number such as # 4 AWG (Ametican Wire Gauge). Then the VOLTAGE DROP can be calculated based on the OHMS/Ft published resistance data. Bear in mind that the typical Mopar reduction drive starter motor is a compound wound design with both series and shunt windings. And this arrangement needs a nomimal voltage, typically greater than 10.5 volts to allow the motor to develop the locked rotor torque (innitial or starting torque). IF LESS than this nominal value occurs, due to voltage drop in the supply cable, the motor will struggle to develop the locked rotor torque and results in slow cranking and HIGHER than normal AMPERAGE draw, which results in even more voltage drop, etc.
The mini starters use permanent magnet fields in lieu of the copper wound field coils. This design requires less voltage to produce more locked rotor torque and subsequently less amperage needed and this will result in lower (less) overall voltage drop.

Moral of the story.....the voltage drop of the supply cable must be determined and provisions to minimize this loss. Likewise, the negative cable to the frame must be the same size as the positive cable.
BOB RENTON
 
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In 2013, I made some changes.
I moved the battery to the trunk. I ran a #2 gauge cable from the positive of the battery to a Ford starter solenoid.
It sits behind the right wheel tub on the other side of that black steel panel.
Trunk battery.JPG


The above is an old picture with another battery but the setup is the same.
On the other side of the solenoid, a 1/0 stranded cable runs up and to the starter. The engine has a ground cable to the core support. There is a ground from engine to battery and from battery to the rear frame rail.
The starter terminals are connected by a buss bar. The starter is activated through the Ford solenoid. A 10ga wire runs from the Mopar starter relay to the Ford solenoid to trigger the starter.
Putting a battery up front to test....I guess I could rig together something stock based to do that.
 
I was thinking the wire you ran was a little off for the application, but when I plugged the numbers in for #2 and for the 1/0 wire (allowing for a 3% voltage drop running 45 amps) you are good for 16 feet and 25 feet respectively. So if the wire is in good condition, that should not be your problem.

1 Wild R/T advice about a short cable to the starter sounds like a great plan to eliminate any other problem with your wiring from the trunk.
 
Now that I have everyone thinking about voltage drop and the reason for it....if you have an opportunity @Kern Dog .....take the battery along to an Auto Electrician and get them to do a "Load Test" on it....to rule out the possibility of a dead or dying cell.
The test takes less than 30 seconds, and hopefully you won't be charged for that (see what I did there) :)

Another thing you could tell us is a little about the lugs that are on the ends of the cables....are they crimped or soldered? If they are soldered, is the connection good enough? If they are crimped, was the correct tool used?

Also, tell us what the CCA of the battery is.....Cold Cranking Amp capacity.
 
maybe that ford solenoid is bad i have had them make my trucks crank slow. the starter solenoid that mopar works good. why the ford starter solenoid ?
 
I am having a similar issue with my A body. I can come out after a few days and it acts like a dead battery. I jump it and its fine for about 24hrs. I thought it was the battery and after checking all the connections again and then again I was mad and just started tapping the starter and it sprang to life. I'm thinking something internally is wrong with the starter. Like the bendix or something is getting hung up.

I just read through this quickly so I apologize if I'm repeating a solved question.
When its not starting whats kind of voltage are you getting at the starter.
 
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