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

[RJRENTON]

On the Mopar starter, the external solenoid does 2 functions:

• It engages the drive pinion gear to the flywheel/converter ring gear via a shifting fork similar to the shifting fork used with manual transmission and throwout bearing
• On the end of the solenoid's plunger is a copper contact washer that connects the battery terminal stud and starter motor winding stud. This washer and both terminals carry the 400+ amps the battery is delivering to the starter and this causes arcing and pitting snd corrosion of these connections over time.

Sometimes the solenoid engages the drive pinion gear but due to corrosion and burning of the high current components the starter motor does not turn and sometimes just tapping on the solenoid causes contact to be made and the starter motor operates. The fix....just replace the copper disc and stationary contacts. Its very seldom the brushes, armature or windings, but it can be the drive pinion clutch...aka "bendix" .
Just my opinion of course.
BOB RENTON

 

[Kern Dog]

To recap, this is not the factory starter. This is a Denso unit, a mini-starter.

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 ?

Here is why:

They have 2 big 5/16" lugs.
Power comes in from one side... (Bottom terminal) Picks up on the other side (Top terminal) and is triggered by the small wire in the middle. The top cable runs up to the starter and is only live when the engine is cranking.
The Chrysler relay only has one 5/16" terminal.
I did try using another solenoid and the results are the same. The cables in the trunk here are in great condition. I still have not been able to check how the 1/0 cable looks at the starter end.
The voltage drops dramatically when trying to start. Even with a fully charged battery now the starter starts turning slow and rapidly slows down with each second of cranking.

 

[Aeronet]

I have a similar problem on the '69 Coronet. If the positive connection on the battery is not perfectly clean it will act like the battery is dying. I have to keep the positive battery terminal and cable connection very clean. It's more critical when it's cold out.
It's the only car I've had that has done that. Mine is all 51 year old wiring.

 

[Kern Dog]

Question out of curiosity...
Has anyone checked the diodes in the alternator? IF one of the diodes in the alternator has shorted, it will drain the battery thru the stator windings. Mopar's alternators (both original round back and the square back design) use a 3 phase full wave bridge rectifier circuit. If a diode short out internally, this will result in a high resistance circuit thru the remaining diodes and stator windings, draining the battery usually over nite or within a few hours.

The alternator is a factory unit, the higher amp version, dual groove pulley and correct for the 1970 model year. When running, the Voltmeter reads approx 15 amps.

 

[khryslerkid]

The alternator is a factory unit, the higher amp version, dual groove pulley and correct for the 1970 model year. When running, the amp gauge reads approx 15 amps.

Does the amp guage ever return to zero? With a fully charged battery and nothing electrical running like lights, blower motor, it should run/return close to zero. 15 amps seems like a lot of output.

 

[Kern Dog]

My mistake: More accurately, the VOLTmeter, not Amp meter or ammeter.
I have aftermarket gauges in the car.
When I turn the ignition to the ON position, the voltmeter drops to around 8 volts. I didn't think that this was unusual because my Power Wagon has an aftermarket Voltmeter and it does the same thing or thereabouts.
The amp gauge probably reflects the alternator properly responding to the need to charge the battery from the high current draw during cranking. It usually does settle back down after a short run time, as if it sensed the reduced need after the battery recovered from the starter application.

 

[khryslerkid]

You stand corrected!

Just for S@G have you ever bypassed the ford solenoid in the trunk. I understand why you are using it. It could be drawing amperage while cranking. Just bolt the two leads together and see if it makes any difference.

 

[Kern Dog]

Bolting the two leads together would result in the starter immediately engaging and staying engaged !
When I release the key to the run position, the starter retracts and the power to it shuts off.
This has worked flawlessly since 2013.

 

[khryslerkid]

Bolting the two leads together would result in the starter immediately engaging and staying engaged !

I thought your leads ran up to the starter relay on your firewall first, then that energized the starter.

 

[Kern Dog]

The reason that I moved the battery to the trunk was for better balance and improved handling. It obviously isn't as convenient as an underhood location. The longer cables add weight too.

 

[Kern Dog]

No, the power runs directly to the starter like stock. From there it deviates though. On the starter, I have a buss bar connecting the big and small terminals together. I have a power wire that does go to the big terminal on the Mopar starter relay so when the key is turned, the system is energized.
I didn't come up with this arrangement myself. A smart mechanic on Moparts posted about it. 383 Man, a guy named Ron. He posts here too.

 

[1 Wild R/T]

If you want to temporarily bypass the ford relay just move both leads to one terminal.... Don't put a nut on it, just slip it on & see if the engine cranks then slip it off.... I doubt it's the relay but I have replaced quite a few through the years....

 

[khryslerkid]

No, the power runs directly to the starter like stock. From there it deviates though. On the starter, I have a buss bar connecting the big and small terminals together. I have a power wire that does go to the big terminal on the Mopar starter relay so when the key is turned, the system is energized.
I didn't come up with this arrangement myself. A smart mechanic on Moparts posted about it. 383 Man, a guy named Ron. He posts here too.

I know Ron well and his word is good if that's what he recommended.

 

[Kern Dog]

If you want to temporarily bypass the ford relay just move both leads to one terminal.... Don't put a nut on it, just slip it on & see if the engine cranks then slip it off.... I doubt it's the relay but I have replaced quite a few through the years....

I could do that. I did try a new one today though and the results were the same. Slow cranking that just got S L O W E R !

 

[1 Wild R/T]

I could do that. I did try a new one today though and the results were the same. Slow cranking that just got S L O W E R !

Just something to consider, last year I put a new relay on an F350 that didn't fix the truck... I'd done a pretty complete testing & diagnosis of the truck so I was kinda baffled for a second, then I did exactly what I described above & it cranked perfectly... I had another truck that the customer didn't plan to fix, grabbed the 15 year old relay off that truck & it worked perfectly... New doesn't mean good...

 

[vance.dykes]

Bolting the two leads together would result in the starter immediately engaging and staying engaged !
When I release the key to the run position, the starter retracts and the power to it shuts off.
This has worked flawlessly since 2013.

if you are using a mini starter like the magnum 360 use's then you have 2 wires going to it and the stock starter solenoid has worked fine for me. i have the main battery cable bolted to the starter from the battery then the solenoid is what energize to crank to start. i'm telling you those ford starter relays build resistance in side.

 

[kiwigtx]

Just for S@G have you ever bypassed the ford solenoid in the trunk. I understand why you are using it. It could be drawing amperage while cranking. Just bolt the two leads together and see if it makes any difference.

I fail to see how a stand alone solenoid will draw 'power' while disengaged. There is a slight cahnce of leakage, but not what we are talking about here.

For clarification @Kern Dog - by the term 'lug' I meant the actual crimp/solder lug on the ends of the cables. We don't refer to the bolts on a solenoid as a lug, they are studs.
This is a crimp lug...

Solder lug...

This is the crimp tool that I use for work normally...

I won't even discuss 'sizes' of lugs, as we are metric here. And we don't normally use AWG as a cable sizing measure....we use a "Cross-sectional area" in terms of square millimeters. The tool pictured above has a rotating head with multiple sizes available....from 6mm up to 120mm for use on copper crimp lugs.

 

[vance.dykes]

I fail to see how a stand alone solenoid will draw 'power' while disengaged. There is a slight cahnce of leakage, but not what we are talking about here.

For clarification @Kern Dog - by the term 'lug' I meant the actual crimp/solder lug on the ends of the cables. We don't refer to the bolts on a solenoid as a lug, they are studs.
This is a crimp lug...
View attachment 963857

Solder lug...
View attachment 963858

This is the crimp tool that I use for work normally...
View attachment 963859

I won't even discuss 'sizes' of lugs, as we are metric here. And we don't normally use AWG as a cable sizing measure....we use a "Cross-sectional area" in terms of square millimeters. The tool pictured above has a rotating head with multiple sizes available....from 6mm up to 120mm for use on copper crimp lugs.

it is not about a drain it seems to have 2 problems to me slow crank and drain and those relays are a moment touch and arc internal and resistances can increase over time

 

[RJRENTON]

IMO....
The Ford starter relay/solenoid is nothing more than a good high current switch, which, when energized, conducts current from the two large terminals. The smaller terminals performed the following: 1) provided power to the internal solenoid coil to cause it to move. 2) The second terminal provided 12 volts to the ignition coil to give it full battery voltage while cranking, bypassing the ballast resistance (Ford used a wire not like Mopar). The reason for this design was the Ford starter used a moving pole piece to engage the starter drive, unlike GM or Mopar's external solenoid. There is nothing magical about this component, its just a high current switch with a good contact structure, relatively inexpensive and easy to replace.
BOB RENTON

 

[Kern Dog]

I went out today and with the battery charged up to THIS number:

....I tried the suggestion by 1 Wild R/T. I took the lead cable off the solenoid and pressed it against the live positive lead. The starter spun faster than it has in awhile.
Hey....Maybe the Ford solenoid , even the new one...is bad?
I connected the cable back and turned the key, Same thing, the starter spun over faster than it has in awhile.

Now I started thinking of this electrical chart that I have in my files....