Electrical problems/need help - The 1947 - Present Chevrolet & GMC Truck Message Board Network

406cid70Chevy · 10-24-2003, 07:28 PM

What would cause the headlights to be dim but when the engine is revved they grow brighter? I've had electrical problems with this truck(70 chevy 3/4ton) ever since I had a mechanic put the motor in. I have MSD ignition. External voltage regulator. I have the starter type with the mini solenoid on top of it (piggyback?).

One day I was driving on the freeway and the battery started getting overcharged and began to boil. I replaced the voltage regulator and got a new battery. But since then I've been having problems. Sometimes the truck will fire up no problem, the next time i'll have to crank and crank and crank...sometimes it won't even start. Then other times when I turn the key over all I get is a "click" sound, no cranking at all. Then sometimes I can be driving along fine and all of the sudden the truck dies out. Sometimes I will start back up after cranking for a bit and other times it won't start. I can't figure out what the problem is.

I've also had to replace two alternators that went bad.
One time I did hook up the battery terminals on the wrong posts for a few seconds, but I was having problems before this, this just probably made it worse. Also one I hook the battery terminals on the CORRECT posts I get a pretty good spark...is that normal?

Also what is that little cylinder-like thing right next to the voltage regulator that has a wire which plugs into the voltage regulator?
Maybe that needed replaced when I replaced the voltage regulator.

Well that's the best I can describe my problems. I hope maybe you guys can help me out with the info I've given.

Sorry for so many questions, I'm not the most knowledgable car guy.

Denny · 10-24-2003, 07:46 PM

If you are getting a spark when you hook up the battery cables, something is drawing juice. I would aso check your wires down at the starter, sounds like you may have a bad on down there. Also check that you have a good ground at the engine, also from engine to body and frame.

406cid70Chevy · 10-24-2003, 09:04 PM

On the starter solenoid there are 3 posts, one for the battery cable, one goes to the distributor I think(it has an.....eh I just took a picture. What does the R and S stand for, the S post leads to the distributor if I remember correctly. There was never any wire connected the the R post, should there be?

jhow66 · 10-24-2003, 09:28 PM

Do you have a point system or HEI? The S post goes to neutral safety switch (if automatic) then to ignition switch--straight to ign. if manuel. The R post goes to the + side of coil if you have point system. If this wire is not there you will not get current to coil when cranking. ( does it start sometime when you let off the key ?) As to the round cylinder it is a condensor to filter out static for your radio. Has nothing to do with running.

jhow66 · 10-24-2003, 09:28 PM

sorry did not see MSD ign.

406cid70Chevy · 10-25-2003, 06:24 PM

bump

Longhorn Man · 10-26-2003, 12:10 AM

Sounds like you are not charging very well at low RPMs...which is normal.
I would toss the alt and regulator in the trash and get an internally regulated one. More amps, and better charging at low RPMs.
Next to the HEI, I think it was one of the best swaps I have done.

pro-flo72 · 10-26-2003, 05:35 AM

i had pretty much the same prblem i ran agood ground from motor to frame then got a smaller pulley from march performance for my altenator worked for me

10-24-2003, 07:28 PM	#1
406cid70Chevy Registered User Join Date: Nov 2002 Posts: 43	Electrical problems/need help What would cause the headlights to be dim but when the engine is revved they grow brighter? I've had electrical problems with this truck(70 chevy 3/4ton) ever since I had a mechanic put the motor in. I have MSD ignition. External voltage regulator. I have the starter type with the mini solenoid on top of it (piggyback?). One day I was driving on the freeway and the battery started getting overcharged and began to boil. I replaced the voltage regulator and got a new battery. But since then I've been having problems. Sometimes the truck will fire up no problem, the next time i'll have to crank and crank and crank...sometimes it won't even start. Then other times when I turn the key over all I get is a "click" sound, no cranking at all. Then sometimes I can be driving along fine and all of the sudden the truck dies out. Sometimes I will start back up after cranking for a bit and other times it won't start. I can't figure out what the problem is. I've also had to replace two alternators that went bad. One time I did hook up the battery terminals on the wrong posts for a few seconds, but I was having problems before this, this just probably made it worse. Also one I hook the battery terminals on the CORRECT posts I get a pretty good spark...is that normal? Also what is that little cylinder-like thing right next to the voltage regulator that has a wire which plugs into the voltage regulator? Maybe that needed replaced when I replaced the voltage regulator. Well that's the best I can describe my problems. I hope maybe you guys can help me out with the info I've given. Sorry for so many questions, I'm not the most knowledgable car guy.

10-24-2003, 07:46 PM	#2
Denny Registered User Join Date: Jul 2002 Location: Cedar Hill, MO Posts: 426	If you are getting a spark when you hook up the battery cables, something is drawing juice. I would aso check your wires down at the starter, sounds like you may have a bad on down there. Also check that you have a good ground at the engine, also from engine to body and frame. __________________ 1969 Chevy C10. Dakota Digital Gauges, 383 Votex Engine, MSD 8361 Distributor, MSD 6A Unit, Demon Carb, Phoenix Transmission 4L80E trans, 3:73 Posi Rear End Early Classics 6 Lug Disc Brakes and Spindles All Stainless Lines

10-24-2003, 09:28 PM	#4
jhow66 Registered User Join Date: Jun 2002 Location: Knoxville Tenn. Posts: 3,058	Do you have a point system or HEI? The S post goes to neutral safety switch (if automatic) then to ignition switch--straight to ign. if manuel. The R post goes to the + side of coil if you have point system. If this wire is not there you will not get current to coil when cranking. ( does it start sometime when you let off the key ?) As to the round cylinder it is a condensor to filter out static for your radio. Has nothing to do with running. __________________ 56 Chevy Bel-Air 2dr. HT (purchased new) 71 Chevy Cheyenne SWB PU (502HO) 65 GMC short bed step--work in progress and my gofer

10-24-2003, 09:28 PM	#5
jhow66 Registered User Join Date: Jun 2002 Location: Knoxville Tenn. Posts: 3,058	sorry did not see MSD ign. __________________ 56 Chevy Bel-Air 2dr. HT (purchased new) 71 Chevy Cheyenne SWB PU (502HO) 65 GMC short bed step--work in progress and my gofer

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10-24-2003, 09:04 PM	#3
406cid70Chevy Registered User Join Date: Nov 2002 Posts: 43	On the starter solenoid there are 3 posts, one for the battery cable, one goes to the distributor I think(it has an.....eh I just took a picture. What does the R and S stand for, the S post leads to the distributor if I remember correctly. There was never any wire connected the the R post, should there be?

10-25-2003, 06:24 PM	#6
406cid70Chevy Registered User Join Date: Nov 2002 Posts: 43	bump

10-26-2003, 12:10 AM	#7
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	Sounds like you are not charging very well at low RPMs...which is normal. I would toss the alt and regulator in the trash and get an internally regulated one. More amps, and better charging at low RPMs. Next to the HEI, I think it was one of the best swaps I have done.

10-26-2003, 05:35 AM	#8
pro-flo72 Registered User Join Date: Aug 2003 Posts: 18	i had pretty much the same prblem i ran agood ground from motor to frame then got a smaller pulley from march performance for my altenator worked for me



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