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Post Info TOPIC: Ok electrical guru's. Figure this one out


A Poncho Legend!

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Ok electrical guru's. Figure this one out


I've been trying to figure out the cause of an electrical problem on the Laurentian. The car quit charging a few weeks ago so I replaced the original alternator and external regulator. I measured voltage across the battery with the car running and got 14.4 Volts. So far so good. Then a few nights later I had the car out with the headlights on and I noticed the headlights would really flicker at idle-slow flickering. They'd go bright then dim and then slowly get brighter than drop off. If I revved the engine it would stop briefly. The dash lights did the same thing. I intalled a volt gauge under the dash and the needle would act very erratically. Sometimes at idle there was no charging at all-the needle would drop below 12 volts. I'd rev the engine and it woud jump-sometimes to 16 volts-shake and then drop to 13 and then fluctuate wildly between 13 and 14. Putting the brakes on would cause the needle to drop to 12v (seems like a lot of draw for brake lights-shouldn't the alternator/regulator "recover" after the initial draw?). Anyway, I suspected a faulty new regulator. I put a new Delco on last night- no change. I disconnected the battery after the car was started-no change. I ran direct grounds from both the alternator and regulator-no change. I thought perhaps the alternator was bad so I put my original back on-STILL NO CHANGE! What the? Still, when everything is flickering, I still get a fairly steady reading at the battery 14.2-14.4. I put the car in gear-no charge at all until I accellerate. I'm stumped by this one. I drove the car last night and the dash lights "pulsate" while driving a steady speed. It behaves like the regulator is slow to activate the solenoids. Its like water building up in a dam and then the pressure reaches a certain point and it releases and then starts to build up again.
Any suggestions? I'm going to start looking at wiring-perhaps I have high resistence in a wire and the current builds up to a certain point and finally overcomes this resistence. The alternator felt pretty hot last night too.

  Todd


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Canadian Poncho Superstar!

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Possibly bad diodes in the alternator.  I had a few of the newer style internal regulator ones do this too.  It was bad diodes.

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Beaumontguru

MY BEAUMONT HAS 4 STUDDED TIRES AND 2 BLOCKHEATERS......AND LOTS OF OIL UNDERNEATH.  The other one has a longer roof.



A Poncho Legend!

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I have alternator (xtra) with good diodes..

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A Poncho Legend!

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Could you have a dirty connection (green corrosion) along the charging circuit somewhere?

That sure sounds like a weird one. That car sat many years, right?

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1966 Strato Chief 2 door, 427 4 speed, 45,000 original miles 

1966 Grande Parisienne, 396 1 of 23 factory air cars



A Poncho Legend!

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Would I have two alternators doing the same thing? The odds seem kind of slim.. The car sat since '78 drenched in oil spray. It came out once in 85 and I suspect it was towed home as I found a towing bill from then. It came out again last year.


-- Edited by 69Laurentian at 22:13, 2008-09-26

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Addicted!

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Not a guru by any means,but i do remember an electrical "guru" telling me that the root of most evil electrical ghosts is in your grounds.So my guess is check grounds everywhere..

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Poncho Master!

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i say kick the tire and swear at it, that sometimes works!!

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Gengiskhan wrote:

Not a guru by any means,but i do remember an electrical "guru" telling me that the root of most evil electrical ghosts is in your grounds.So my guess is check grounds everywhere..




 Dido ,it does sound like a short or ground fault weirdface



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you know sounds like a loose connectoin some where.

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Poncho Master!

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I would also say it's a ground issue. My engine ground was off and then grounded thru the tranny cable.

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Uber Guru

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sounds like a ground problem possibly...
battery ground lead (smaller guage) bolts to the fender,
volt reg bolts to the rad support,
we used to see the rad support lose ground connection to the fender.
also be sure the alt. has clean grounds where mounted on the engine.

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A Poncho Legend!

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I've run jumpers from the alternator to ground (at the battery) as well as from the regulator to the battery. No change..


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A Poncho Legend!

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I know this isn't a great way to diagnose, but do you have anyone you know close by who has a known good regulator and alternator that you could try on your car?

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1966 Strato Chief 2 door, 427 4 speed, 45,000 original miles 

1966 Grande Parisienne, 396 1 of 23 factory air cars



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455gto wrote:

I would also say it's a ground issue. My engine ground was off and then grounded thru the tranny cable.




  My buddy's old Trans Am had the same problem, grounding thru the trans cable...Went thru 3 cables before we realized what it was. 



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1960 Laurentian Safari 
1960 Laurentian 4door(scrapped)
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2002 Hyundai Accent(SOLD)
1968 Grand Parisienne Scrapped and SOLD

 

Calgary, Alberta, but raised in Peterborough



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Could be a faulty headlight switch. It's a quick change out if you have another one.

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A Poncho Legend!

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I don't think it's the headlight switch as the volt gauge is not on the same circuit and it still fluctuates with the lights off. What I don't get is sometimes at idle I'll get no charge at all-it falls to 12 volts and sometimes a bit below. Sixtywagon: What ground was missing on your buddy's Trans Am? My cowl to engine grounds are present..


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A Poncho Legend!

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You should have engine to frame, body to frame and engine to body grounds, correct?

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1966 Strato Chief 2 door, 427 4 speed, 45,000 original miles 

1966 Grande Parisienne, 396 1 of 23 factory air cars



Guru

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Pull all your fuses out and pop them in one at a time till the problem re-surfaces.
This should put you in the ball park.
Definitely sounds like a bad connection/ground. Does the engine still have the factory copper grounding straps from the valve covers to the firewall?
You can also, unbolt every ground/connection and wire-brush the surface of both and reseat.
Hmmmmmm, also, have you changed the battery out for a known good one, a bad/shorting cell might act similar.
Now tht I think of it.
I'd swap the battery first.

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65 Catalina 2+2 421 4bbl,  Auto, White, w/red interior, Buckets w/column shift.

66 Grande Parisienne, 2dr HT, 327 4bbl, Auto.

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Both still require a lot of work.


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69Laurentian wrote:

I don't think it's the headlight switch as the volt gauge is not on the same circuit and it still fluctuates with the lights off. What I don't get is sometimes at idle I'll get no charge at all-it falls to 12 volts and sometimes a bit below. Sixtywagon: What ground was missing on your buddy's Trans Am? My cowl to engine grounds are present..



  It was the Engine to Firewall, had broken off due to a bad motor mount and too many brake stands...biggrin



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1960 Pontiac Strato Chief Safari
1960 Laurentian Safari 
1960 Laurentian 4door(scrapped)
2001 Grand Am Traded on a '96 Suburban 2WD
2002 Hyundai Accent(SOLD)
1968 Grand Parisienne Scrapped and SOLD

 

Calgary, Alberta, but raised in Peterborough



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I have the ground straps on the valve covers. I have even disconnected the battery after the car is running- no change. I've ruled out bad connections at the starter as if they were bad I'd assume it wouldn't engage. I'd convert to a internally regulated alternator but I have a fair bit of $$ invested in the new alternator and regulator..


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Guru

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have you tried pulling fuses to see if one particular circuit is shorting etc.?

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65 Catalina 2+2 421 4bbl,  Auto, White, w/red interior, Buckets w/column shift.

66 Grande Parisienne, 2dr HT, 327 4bbl, Auto.

Had the 66 since about 83 and the 65 since 88.
Both still require a lot of work.


Guru

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The regulator is on the fenderwell or rad support?
Check the ground to the frame from there?

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65 Catalina 2+2 421 4bbl,  Auto, White, w/red interior, Buckets w/column shift.

66 Grande Parisienne, 2dr HT, 327 4bbl, Auto.

Had the 66 since about 83 and the 65 since 88.
Both still require a lot of work.


A Poncho Legend!

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The regulator is on the rad support. Shouldn't running a ground from the regulator to the battery eliminate this as a possible problem? I did that and there was no change. I just spent an hour with it and it really has me boggled. I pulled the cover off the regulator and sure enough, the little relay in there moves in relation to the volt gauge. There is no pattern. I filmed the gauge and will post the video on Youtube later. Sometimes it will sit steady at 14 volts, other times it will drop to 13 then slowly creep to 14 and then the relay in the regulator kicks in and it drops down to 13. Other times it will switch fast. It does this with the headlights on or off. Funny though, with the high beams on the gauge is steady at just over 12volts. Does anyone on here have the same system with a volt gauge? What does your gauge do?

Todd


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Poncho Master!

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When you have the high beams on does the gauge match the reading from your meter on the battery? The headlights ground on the rad support as well as the regulator. Maybe you have a bad ground on one of the headlight grounds or a bad headlight bulb. Unplugging the headlights will let you know pretty quickly.
 To eliminate the headlight switch just unplug it.
 You could try exciting the alternator manually with the plug disconnected. Also run the power wire directly to the battery to eliminate the junction block.

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A Poncho Legend!

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I talked to a friend tonight and he said a bad field wire will cause all kinds of problems. I'll bypass that wire first and see what happens..


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