Had a major electrical problem while cruising today, and for the first time in over six years, Suzi-Q had us stranded on the side of the road: Cruising along the highway and all is well, then suddenly all power goes out, GEN light comes on for a few seconds, bird poops out along the side of the road. No power going to any circuits (I have HEI by the way)......DANG! I tinker around a bit, but there in nothing obvious to work on...no burning wires, no hot battery, nothing looks wrong. After about 15 minutes....suddenly full power pops back on! I noticed it because my door was open and suddenly the overhead light came on. She she starts right up. See below for part two...
'68 428 HO M3 Monster, 4-on-the-floor! Need I say more?
We turn around of course and head home. 10 minutes into that and the same thing happens again...complete power out, GEN light comes on for a few seconds, bird poops out along the side of the road. No power going to any gages, lights, ignition, etc. Being fast learners, we sit and wait, and sure enough after about 15 minutes suddenly we have full power again. Lights are back, gages are back, she starts right up and we make it home.
What in our electrical systems would cause complete shut-down of power to all electrical circuits, and then come back on again after a 15-minute wait?
'68 428 HO M3 Monster, 4-on-the-floor! Need I say more?
That wouldn't make the car have no power. There is a difference between no power and no spark, the a related union because you cannot have spark if you don't have power.
I always jump on ground like stinkonshit. Clean the terminals, meaning with crome like sheen, and use a light coat of vasiline.
Dew dee car have a fusible link or a ballast resister? I think that the 8 has a ballast resister, but I get in trouble when I think. Again making the mistake of thinking, I think that Mopar and its ballast resister netted total power loss.
Can you hang a link to a schematic so I can look it over?
Had a similar problem years ago, the connection at the junction block near the battery from the positive to the alternator was bad(corroded out), also the breaker on the fire wall that feeds 12 volts may be a suspect. A couple of places to start anyway.
I've never had one of those modules go out but that makes sense. Nash, you don't have an MSD box do you? I've heard other people complain that they have experienced shut down occasionally when they get hot. Mine never has. I'm not sure if that's how it reacts when it does. Just thinking.
Merv, I disconnected the new horn relay the first time power went out, thinking like you that it may have caused the problem. But it happened again 15 minutes later so thats not it. No, I do not have an MSD box Firebob. Battery and terminals are spotless.
The list of possibilities as to whats causing this has to be very short: Complete power loss (with battery showing 12+ volts strong), followed by the system "resetting" itself after 10-15 minutes. Where in our circuitry is a component that could do that?
'68 428 HO M3 Monster, 4-on-the-floor! Need I say more?
I have had this problem years ago ('62 Belaire). The car would loose all electrical power and if rolling at the time, the gen light would come on until engine stopped turning. The problem was the main electrical connector at the firewall. The contacts were corroded inside. I opened it up and cleaned the corrosion as good as I could and that fixed it for the most part. It still did it from time to time though. I think some of that electrical gel might help. Had a similar problem on my van afew years back and my mechanic pointed out how water was channeled off of the hood over that connection.
I had a problem similar to this in my old 74 Dodge Power Wagon. When driving it for a while, it would suddenly loose all power and die until the engine cooled down a while, and then everything was fine again. It was a balast resistor, that was mounted on the firewall. not sure if the birds have something like that.
Check the connection at the starter. All that juice flowing from the positive terminal on your battery does not go directly to the fusebox, it goes to the starter first, then to the rest of the chassis. You could have a short in the starter, or a loose positive terminal down there.
Since you said ALL power is cut, I think that's the only thing that could cut ALL power, including ignition, electrics, and starter, so I don't think it could be a relay or HEI module problem. The fusible link is a possibility, that would also cut all power to the interior, etc, as well as ignition. They're designed to melt and disconnect when too much power goes through them, but do they re-fuse themselves?
Had one that would either die and wouldnt restart till cooled off. Or not turn over when hot. One or the outer, maybe both(the 70's ;)) Turned out to be a bad cell in battery.
I would second the ignition switch. $15 from AutoZone. That would kill all the power in the car.
I would just do a few simple checks:
Battery cables at the battery Battery cable at the block (ground) Battery cable at the starter. Connection point at the positive lead behind the battery. Connection point at the horn relay. Pull the electrical plug at the firewall and check the connections.
1 - rohrt, why would a faulty ignition switch kill all power to lights, gages, etc? 2 - This is not a HOT problem, engine was normal temp, battery and terminals all cool to the touch, nothing hot anywhere. 3 - No issues with battery main cables and connections.
'68 428 HO M3 Monster, 4-on-the-floor! Need I say more?
Stealthbird, not to poke you in the eye or anything, I appreciate all help here...but the POS power from the battery does not go to just the starter first. There is a second POS wire coming off the POS battery terminal that goes to a junction terminal right in front of the battery on the radiator support. That line contains a fusible link as you mentioned. From there it goes to the voltage regulator, alternator and horn relay.
'68 428 HO M3 Monster, 4-on-the-floor! Need I say more?
Have you checked the battery when it is dead (ie perhaps faulty intermittent cel?)
Really the only thing you can do is duplicate the situation and quickly check all along the accessory line until you find the spot you no longer have voltage. That's the beotch about those intermittent faults!!
Unless something is different on your car....my positive cable goes directly to the starter solenoid, then another wire from the solenoid goes to the ignition switch, etc.
I was suggesting that perhaps the solenoid stud or something in the solenoid may be broken. That would explain a total loss of power, lights and all, and maybe it has something to do with after the car heats up.
Had this problem years ago on my first bird. ALL power lost gen light on till motor stopped turning. Get out of the car open the hood and slam it as hard as you could and it would come back on. Worked good on a couple of dates. Electrical connector at firewall. Pontiacs do not have mopar ballast resitors. It's rusted up in the connector, clean it grease it and reseat it.
I'd be focused on that junction terminal and also the cables to/from it. I'd also take a voltmeter with you and take it for a drive. And a cellphone.
X2 on that. With a voltmeter and little luck, you should be able to find this. Not that I have ever had this particular problem, but I would suspect a bad connection somewhere. Start at the battery and start tracing the 12 volts back to the fuse block in the car (when it is dead).
Stealth, the 68 V8 wiring is different than your diagram. Main POS goes from battery to starter, but a smaller wire also comes off the POS battery terminal to a juntion terminal, and then on to horn relay, voltage regulator and eventually to fuse box to power the car accesories.
You all talking about the firewall electric connector behind the brake booster assembly? Man, how to you get to and disconnect that?
I hear ya! I took one off of a parts car that didn't have the front clip on, and I still had a h3ll of a time getting it off!
I used to be indecisive. Now I'm not sure. I feel like I am diagonally parked in a parallel universe. 1968 400 convertible (Scarlet) 1976 T/A - 455 LE (No Burt) 1976 T/A New baby, starting full restoration. 1968 350 - 4 speed 'vert - 400 clone (the Beast!) 1968 350 convertible - Wife's car now- 400 clone (Aleutian Blue) (Blue Angel) 2008 Durango - DD 2008 GXP - New one from NH is AWESOME! 2017 Durango Citadel - Modern is nice! HEMI is amazing! 1998 Silverado Z71 - Father-daughter project 1968 400 coupe - R/A clone (Blue Pearl) (sold) 1967 326 convertible - Sold 1980 T/A SE Bandit - Sold
OK, got it off rather easily using a wobbler 3/8 socket and 12 inch extension, not as bad as I thought. This connector is probably the only one I have never messed with/replaced/etc over the years. Wow, it is indeed ugly on the inside but that may just be 43-year-old electric grease in there making it look so bad.
Sprayed both connectors down heavily with rust buster and cleaner, then brushed for quite a while, and will blow both connectors out with air tomorrow. Only one way to find out if this is the fix for my problem.....
'68 428 HO M3 Monster, 4-on-the-floor! Need I say more?
... clean it and use new dielectric grease on it before reassembling. I would still trace it back first with multimeter in your glove box for the next cruise in case it persists. I hope that does it tho!
Last edited by Dave's White Rock '68 Droptop; 03/17/1104:43 PM.
I used to be indecisive. Now I'm not sure. I feel like I am diagonally parked in a parallel universe. 1968 400 convertible (Scarlet) 1976 T/A - 455 LE (No Burt) 1976 T/A New baby, starting full restoration. 1968 350 - 4 speed 'vert - 400 clone (the Beast!) 1968 350 convertible - Wife's car now- 400 clone (Aleutian Blue) (Blue Angel) 2008 Durango - DD 2008 GXP - New one from NH is AWESOME! 2017 Durango Citadel - Modern is nice! HEMI is amazing! 1998 Silverado Z71 - Father-daughter project 1968 400 coupe - R/A clone (Blue Pearl) (sold) 1967 326 convertible - Sold 1980 T/A SE Bandit - Sold