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Diagnosing charging system health '70 Barracuda EFI

Started by Mopsquad, June 14, 2019, 11:12:35 AM

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Mopsquad

Quote from: crackedback on June 15, 2019, 02:04:56 PM
I'm not far from you over in Indio.

I build the 6 and 8ga charge wires with a fusible link.  Try to make them stealthy as well.   Simple to install.  I may have an ad up here somewhere.

Where are you tapping the system for your EFI?    Battery or starter relay on our mopars is a horrible spot with the factory charging system.

Let me know if I can help.

Thank you. I will certainly contact and inquire.

The EFI and MSD battery source are tapped at the junction pictured.

Mopsquad

Quote from: Chryco Psycho on June 15, 2019, 01:40:25 PM
The large stud on the Alt  with the 1/2" nut & the start relay , 1 wire from the positive battery terminal bolts to the relay

Is this the stud on the alternator that I tap into? Black plastic cover

See pic


crackedback



Mopsquad

Quote from: crackedback on June 15, 2019, 03:29:15 PM
That's the starter relay.

I used it as a junction block to limit the amount of wires direct to battery pole.

YellowThumper

Quote from: Mopsquad on June 15, 2019, 03:07:59 PM
Quote from: Chryco Psycho on June 15, 2019, 01:40:25 PM
The large stud on the Alt  with the 1/2" nut & the start relay , 1 wire from the positive battery terminal bolts to the relay

Is this the stud on the alternator that I tap into? Black plastic cover

See pic
Yes that is correct alt stud. Notice how small the factory wire is... now picture that and only a blade terminal thru bulkhead.
Life is to be viewed thru the windshield. Not rear view mirror.
You are the only one in charge of your destiny.

Mike.

Mopsquad

Quote from: YellowThumper on June 15, 2019, 04:00:01 PM
Quote from: Mopsquad on June 15, 2019, 03:07:59 PM
Quote from: Chryco Psycho on June 15, 2019, 01:40:25 PM
The large stud on the Alt  with the 1/2" nut & the start relay , 1 wire from the positive battery terminal bolts to the relay

Is this the stud on the alternator that I tap into? Black plastic cover

See pic
Yes that is correct alt stud. Notice how small the factory wire is... now picture that and only a blade terminal thru bulkhead.

Thx. So I'll directly connect a 8ga wire from that pole to the battery.

crackedback

That wire MUST have circuit protection of some kind.

Yeah, people use the starter relay as a bus point and it's a horrible place to do it on our cars without the wire around set up.


73440


Mopsquad

Quote from: crackedback on June 15, 2019, 04:57:55 PM
That wire MUST have circuit protection of some kind.

Yeah, people use the starter relay as a bus point and it's a horrible place to do it on our cars without the wire around set up.

I can use a separate junction pole outboard of the relay and use a 8 ga or so to connect to battery.

What amp fuseable link?

RCman

I'm also going with the stock alternator doesn't have enough gusto to keep up with the EFI / electronic ignition demands.
I ran into this exact same issue. I ended up grabbing some brackets from AR Engineering from Mancini Racing (Brad's post linked it) so I can run a Denso alternator for a 4cyl 2.4L 4Runner from 85-92 which has the same style v-belt pulley. 93-95 will also have a v-belt pulley but is a different plug end. Mancini has the plug and wiring for the 85-92 style. I now have no problem with 14.1+ V at idle. It is a slick setup and super easy to do, especially if you've already run the wire from the alt to the starter relay/battery (with protection of course).

Mopsquad

Quote from: RCman on June 15, 2019, 06:02:25 PM
I'm also going with the stock alternator doesn't have enough gusto to keep up with the EFI / electronic ignition demands.
I ran into this exact same issue. I ended up grabbing some brackets from AR Engineering from Mancini Racing (Brad's post linked it) so I can run a Denso alternator for a 4cyl 2.4L 4Runner from 85-92 which has the same style v-belt pulley. 93-95 will also have a v-belt pulley but is a different plug end. Mancini has the plug and wiring for the 85-92 style. I now have no problem with 14.1+ V at idle. It is a slick setup and super easy to do, especially if you've already run the wire from the alt to the starter relay/battery (with protection of course).
.

Thx for the suggestion. I'm going to test the alt first.


1 Wild R/T

My stock frame round back style alternator with upgraded diodes will push 85 amps so I see no need to put a Japanese alternator on my car....  I know the Denso's work great & I'm not saying thee's anything wrong with doing the change, I just prefer to keep my car "looking" stock...

73440

Example,
10 Ga. wire, 14 Ga. fusible link.
8 Ga. wire, 12 Ga. fusible link.

Chryco Psycho

You have already proven there is more load than the alt can handle at idle so if you get caught in traffic you can run the battery dead & fairly quickly too as you have proven  , so My belief is you need to upgrade the alternator output to keep up with the load wether you modify the stock alt as Wild suggests or change to a high output one you will have to do it  , I have run into this a few times now with modern upgrades !
  You absolutely still need the bypass especially if the alt can produce more than 60 amps as the ammeter gauge cannot handle more than 60 amps & the connections through the bulkhead do not like 60 amps either .

Mopsquad

Quote from: Chryco Psycho on June 15, 2019, 08:05:46 PM
You have already proven there is more load than the alt can handle at idle so if you get caught in traffic you can run the battery dead & fairly quickly too as you have proven  , so My belief is you need to upgrade the alternator output to keep up with the load wether you modify the stock alt as Wild suggests or change to a high output one you will have to do it  , I have run into this a few times now with modern upgrades !
  You absolutely still need the bypass especially if the alt can produce more than 60 amps as the ammeter gauge cannot handle more than 60 amps & the connections through the bulkhead do not like 60 amps either .

I can see a new alternator in my future. I'm curious about this bypass test with 8ga wire. Can I just temporarily connect the 8ga wire from alt stud to battery to test voltage?  I had to read up on what a fuseable link was - didn't know. For this test, can I not use a link?