rather than dredge up an old post..........

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rather than dredge up an old post..........

Postby rtm » Fri Mar 22, 2013 5:20 pm

I wired my alternator into my battery cutoff switch using the two wires that plug into the side of the alternator, (small brown wire to one small post of cutoff switch, red wire from same connector at alt. to the other small post of cutoff switch.)
when the switch is left on, this causes a drain in my charging system.
I remember spence telling me to wire in a diode, or light bulb (to prevent this problem?) :oops:
if so, what am I looking for in a diode (as far as values? ) do they have a polarity? (blue stripe comes to mind)
another issue I am experiencing is; after driving the vehicle , and shutting it off, I have to jump start it (due to a semi- discharged battery, I believe)
The battery does not seem to charge during normal operation.
the volt meter struggles to maintain 13 volts while driving. (100 amp alt.)
poor ground?
battery is in trunk, I used 1 gauge wire to feed everything forward,
and grounded the battery to a roll cage plate in the trunk, which is welded to a factory subframe point.
I have sub frame connectors.
I grounded the block to the S.F. connector,and firewall
also grounded transmission case to S.F. connector (because someone recommended it.)
I have a mechanic friend who told me to run a ground wire from battery (neg. post) to starter bolt.
Is this necessary?
I think I have a two fold problem, but they may be related.

BTW. when at idle (750 RPM) the idiot light on the dash is visible(GENERATOR)
at higher RPM it goes out.
I turned the idle up, thinking it would help, but, :bang:
I have yet to take a long trip, or drive at night , because of these issues.


thanx for any help guys

rick the mason
rtm
 
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Re: rather than dredge up an old post..........

Postby duckblaster67 » Sat Mar 23, 2013 1:54 am

Wilson Electric makes an adaptor with a built-in diode that just plugs in between the alt and the original plug-in! I believe the part # is 20-01-9030?? I can check at work for sure!
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Re: rather than dredge up an old post..........

Postby spencerforhire » Sat Mar 23, 2013 7:27 am

Your alternator should make 14.4-14.8 volts; maybe a little less at idle if you have normal sized pulleys. It doesn't sound like you've got a ground problem, but you should check is there's a difference in voltage between the post on the back of the aIternator and the battery in the back. I'm still trying to decipher how you've got the alternator wired; it looks like the way you've got it now it's on all the time killing your battery. If you want the battery switch to shut off the alternator, you would need to run the brown switched lead from the light in the dash to one small terminal of the battery cutoff switch and then the other small terminal goes to the brown on the alternator.. The diode or light in series with this circuit keeps the vehicle from running on after you shut off the ignition. If you're using a diode, the band or stripe goes toward the alternator. But your light still works, so the diode isn't really necessary.
My race car has a "charge" light in the alternator circuit(good thing too; I flipped a belt one time and knew instantly), and even with underdrive pulleys I've got full voltage by 1500rpm(idle speed with a big cam). The 2 small terminals on my battery master switch are wired to shut off the ignition power to the MSD box instead of the alternator.
The "fleet"-
72 Vega HB Drag Car -383/'Glide/9"(9.35@146.19)(5.94@117.28 1/8th)
77 Vega Estate wagon- project(someday)will have TPI305/T-5, S-10 spindles/axles
76 Vega GT- 400/4spd/9" retired from active duty(rusty)
06 Silverado 2WD ex.cab daily
03 Silverado 2WD ex.cab (retired)
06 Haulin' 20ft enclosed car transporter
06 GMC Canyon Shop truck
07 Colorado project( 5.3 4L60e swap)
99 Saturn SL1- wife's car
01 Saturn SC2- son's project
07 Saturn Ion Redline project
and 4 more Saturn "parts cars"
Note- the very act of listing all of these has made me realize I have some kind of problem.....

Visit http://www.spencerforhire.ca
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Re: rather than dredge up an old post..........

Postby rtm » Sat Mar 23, 2013 9:11 am

My bad Spence,
I DID only run the two ends of the brown wire to the two small posts on my taylor switch.
It does cause a drain at the battery though, (switch on, car off), not sure why.
When running ,the alternator is only developing about 13.5 volts at idle.
I believe I have a smaller than stock pulley on the alt, which would make it spin faster.
Is this detrimental?
rtm
 
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Re: rather than dredge up an old post..........

Postby spencerforhire » Sun Mar 24, 2013 7:51 am

You had me worried there with the description of how you had the switch wired. Are you sure the drain is from the alternator? The brown wire is from the "GEN" light in the cluster that has ignition switched power on it. No way it can draw power with the key off. Where is the 2nd( red) wire in the alt plug hooked up? It should go to the post on the back with the big red.
The smaller pulley would make the alternator run faster, not slower so that's not the source of the low voltage at charge. Normally, the alternator runs about 3X engine RPM, and you have to be down around 1.5x RPM before you start to have trouble charging at idle. It all depends upon the alternator; what exactly is on there?

Edit:- I just had a thought; if you had the 2 wires(brown & red) mixed up in the alternator plug, the alternator would be on all the time the master switch is on regardless of key position and not only would it kill the battery, it wouldn't charge properly either. If you have a normal 1970's GM alternator, the terminal closest to the post on the back is the brown.
The "fleet"-
72 Vega HB Drag Car -383/'Glide/9"(9.35@146.19)(5.94@117.28 1/8th)
77 Vega Estate wagon- project(someday)will have TPI305/T-5, S-10 spindles/axles
76 Vega GT- 400/4spd/9" retired from active duty(rusty)
06 Silverado 2WD ex.cab daily
03 Silverado 2WD ex.cab (retired)
06 Haulin' 20ft enclosed car transporter
06 GMC Canyon Shop truck
07 Colorado project( 5.3 4L60e swap)
99 Saturn SL1- wife's car
01 Saturn SC2- son's project
07 Saturn Ion Redline project
and 4 more Saturn "parts cars"
Note- the very act of listing all of these has made me realize I have some kind of problem.....

Visit http://www.spencerforhire.ca
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Re: rather than dredge up an old post..........

Postby rtm » Sun Mar 24, 2013 2:12 pm

From your description spence, everything appears correct,
the two wire pigtail at the side of the alternator is wired correctly.
In the factory G.M. harness,there is a large (10 gauge? )red wire from the bulkhead connector,
it splits at a soldered junction into three.
Of these three, two go to my alternator, one to the post in back , the other to the lower slot in the
pigtail on the side.
the other wire, which has a fusible link, is routed to the positive post I have up front on the firewall, (which is powered by my trunk mounted battery).
does this sound correct?

with my key off, the small brown wire at alternator is drawing 0.05 volts,

the three red wires I mentioned, obviously are reading whatever the battery voltage is at the time,
as they are all joined to the positive side of the battery.
Is this normal?
rtm
 
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1976 Chevrolet Monza Towne Coupe

Re: rather than dredge up an old post..........

Postby spencerforhire » Sun Mar 24, 2013 4:53 pm

Sounds like the wiring is all correct. If you unplug the alternator does the drain stop? There could be something wrong inside the alternator or in the cluster wiring.
The "fleet"-
72 Vega HB Drag Car -383/'Glide/9"(9.35@146.19)(5.94@117.28 1/8th)
77 Vega Estate wagon- project(someday)will have TPI305/T-5, S-10 spindles/axles
76 Vega GT- 400/4spd/9" retired from active duty(rusty)
06 Silverado 2WD ex.cab daily
03 Silverado 2WD ex.cab (retired)
06 Haulin' 20ft enclosed car transporter
06 GMC Canyon Shop truck
07 Colorado project( 5.3 4L60e swap)
99 Saturn SL1- wife's car
01 Saturn SC2- son's project
07 Saturn Ion Redline project
and 4 more Saturn "parts cars"
Note- the very act of listing all of these has made me realize I have some kind of problem.....

Visit http://www.spencerforhire.ca
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Re: rather than dredge up an old post..........

Postby rtm » Sun Mar 24, 2013 8:17 pm

spencerforhire wrote:Sounds like the wiring is all correct. If you unplug the alternator does the drain stop? There could be something wrong inside the alternator or in the cluster wiring.


yes, it does, will have alt. tested before I rip anything else apart.
may have to upgrade to higher amperage alt. anyway.
rtm
 
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Re: rather than dredge up an old post..........

Postby duckblaster67 » Sun Mar 24, 2013 10:01 pm

Sounds like it probably has a diode or 2 burnt out in it.
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Re: rather than dredge up an old post..........

Postby spencerforhire » Mon Mar 25, 2013 7:17 am

Alternator upgrade is always a good idea especially if you have aftermarket electric fan and fuel pump and ignition box; all these things draw a lot of current. I still don't understand some drag racers who don't run any alternator; whatever few HP it takes to run the thing surely is made up for by a hotter spark and more consistent fuel delivery. Just one of my pet peeves.
The "fleet"-
72 Vega HB Drag Car -383/'Glide/9"(9.35@146.19)(5.94@117.28 1/8th)
77 Vega Estate wagon- project(someday)will have TPI305/T-5, S-10 spindles/axles
76 Vega GT- 400/4spd/9" retired from active duty(rusty)
06 Silverado 2WD ex.cab daily
03 Silverado 2WD ex.cab (retired)
06 Haulin' 20ft enclosed car transporter
06 GMC Canyon Shop truck
07 Colorado project( 5.3 4L60e swap)
99 Saturn SL1- wife's car
01 Saturn SC2- son's project
07 Saturn Ion Redline project
and 4 more Saturn "parts cars"
Note- the very act of listing all of these has made me realize I have some kind of problem.....

Visit http://www.spencerforhire.ca
User avatar
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Re: rather than dredge up an old post..........

Postby rtm » Wed Mar 27, 2013 8:10 am

spencerforhire wrote:Alternator upgrade is always a good idea especially if you have aftermarket electric fan and fuel pump and ignition box; all these things draw a lot of current. I still don't understand some drag racers who don't run any alternator; whatever few HP it takes to run the thing surely is made up for by a hotter spark and more consistent fuel delivery. Just one of my pet peeves.



will 120 amp be sufficient? I have twin spal fans up front, a trans cooler fan under car
mallory 140 gph. fuel pump ,as well as everything G.M. installed (no A/C ).
NO stereo installed either., but that may change someday.
rtm
 
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Joined: Thu Jan 31, 2008 9:06 pm
Location: new hartford conn.

1976 Chevrolet Monza Towne Coupe

Re: rather than dredge up an old post..........

Postby spencerforhire » Wed Mar 27, 2013 11:10 am

120 amp should be fine. The original 1970's GM
alternator had less than half that capacity.
The "fleet"-
72 Vega HB Drag Car -383/'Glide/9"(9.35@146.19)(5.94@117.28 1/8th)
77 Vega Estate wagon- project(someday)will have TPI305/T-5, S-10 spindles/axles
76 Vega GT- 400/4spd/9" retired from active duty(rusty)
06 Silverado 2WD ex.cab daily
03 Silverado 2WD ex.cab (retired)
06 Haulin' 20ft enclosed car transporter
06 GMC Canyon Shop truck
07 Colorado project( 5.3 4L60e swap)
99 Saturn SL1- wife's car
01 Saturn SC2- son's project
07 Saturn Ion Redline project
and 4 more Saturn "parts cars"
Note- the very act of listing all of these has made me realize I have some kind of problem.....

Visit http://www.spencerforhire.ca
User avatar
spencerforhire
 
Posts: 2442
Joined: Mon Jul 03, 2006 9:02 pm
Location: Halifax, Nova Scotia

1972 Chevrolet Vega Hatchback

Re: rather than dredge up an old post..........

Postby spencerforhire » Wed Mar 27, 2013 11:11 am

120 amp should be fine. The original 1970's GM
alternator had less than half that capacity.
The "fleet"-
72 Vega HB Drag Car -383/'Glide/9"(9.35@146.19)(5.94@117.28 1/8th)
77 Vega Estate wagon- project(someday)will have TPI305/T-5, S-10 spindles/axles
76 Vega GT- 400/4spd/9" retired from active duty(rusty)
06 Silverado 2WD ex.cab daily
03 Silverado 2WD ex.cab (retired)
06 Haulin' 20ft enclosed car transporter
06 GMC Canyon Shop truck
07 Colorado project( 5.3 4L60e swap)
99 Saturn SL1- wife's car
01 Saturn SC2- son's project
07 Saturn Ion Redline project
and 4 more Saturn "parts cars"
Note- the very act of listing all of these has made me realize I have some kind of problem.....

Visit http://www.spencerforhire.ca
User avatar
spencerforhire
 
Posts: 2442
Joined: Mon Jul 03, 2006 9:02 pm
Location: Halifax, Nova Scotia

1972 Chevrolet Vega Hatchback

Re: rather than dredge up an old post..........

Postby rtm » Wed Apr 03, 2013 4:58 pm

update; A local starter/alternator rebuilder loaned me a C.S. 130 alternator.
car runs fine, battery charges normally.
These units have higher amps at idle, I believe.
Trouble is, it is a one wire alternator.
I have my taylor four pole switch wired to the brown "exciter" wire (to kill alternator power)
with the one wire unit, the car will now continue to run.
I drove it to the guy's shop, and showed him my dilemma.
He's going to put together an alternator that has the higher amps at idle, but can still be wired like my previous one. I will ask him what he's using for internals in the "hybrid" unit.
I may have to lose the factory pigtail, but, he will show me which pins to use(the c.s. unit has a four pin connector) to make it work.
I'm just glad I figured out my issue,I'm tired of second guessing myself, :rolleyes: and tearing into my wiring harness. :bang:
now I can concentrate on other aspects of my build, and, I can finally drive the car. :th:
rtm
 
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Joined: Thu Jan 31, 2008 9:06 pm
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1976 Chevrolet Monza Towne Coupe

Re: rather than dredge up an old post..........

Postby spencerforhire » Wed Apr 03, 2013 5:12 pm

You can use the one wire alternator; use the other 2 terminals of the battery switch to interrupt ignition power to the distributor or ignition box instead .
The "fleet"-
72 Vega HB Drag Car -383/'Glide/9"(9.35@146.19)(5.94@117.28 1/8th)
77 Vega Estate wagon- project(someday)will have TPI305/T-5, S-10 spindles/axles
76 Vega GT- 400/4spd/9" retired from active duty(rusty)
06 Silverado 2WD ex.cab daily
03 Silverado 2WD ex.cab (retired)
06 Haulin' 20ft enclosed car transporter
06 GMC Canyon Shop truck
07 Colorado project( 5.3 4L60e swap)
99 Saturn SL1- wife's car
01 Saturn SC2- son's project
07 Saturn Ion Redline project
and 4 more Saturn "parts cars"
Note- the very act of listing all of these has made me realize I have some kind of problem.....

Visit http://www.spencerforhire.ca
User avatar
spencerforhire
 
Posts: 2442
Joined: Mon Jul 03, 2006 9:02 pm
Location: Halifax, Nova Scotia

1972 Chevrolet Vega Hatchback

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