Voltage issues

iamtherealJayy

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Spent $340 today on two batteries… one for work truck and one for the 76. Work truck cranked and started after a few cranks, ran like absolute garbage sounded terrible smelled terrible running absurdly rich and shooting massive flames from exhaust. Initial timing is at 8° btdc. Mechanical advance works, not positive on vacuum advance. Timing was at 4° because “too much advance will crank slow” so I retarded it slightly. My voltage issue has got to be within the starter somewhere since that’s all I’ve changed recently. But what would cause the truck to run absurdly rich all of a sudden? I’ve been getting alright fuel mileage the truck hasn’t been backfiring and today it’s doing all of the above and drinking fuel. Vacuum reading is right at 19/20 at idle. I’m going to go change the battery on the 76 and see if it cranks once warm while waiting on the 78 to cool off so I can work on the pos.
 

iamtherealJayy

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** meant to insert this video.
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Revving from idle to ~3500 rpm.
Edit: there’s also a new noise that sounds similar to a blow off valve or turbo flutter in a way. Here’s a clip
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iamtherealJayy

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I think I found an issue on the work truck. The solenoid is missing a bolt and it moves, all connections are tight except that, also the “turbo” noise is the alternator lol. Is this missing bolt/screw an easy to replace one like can I obtain it from a parts bin ? Or is it some specialty bolt? I did not get to put the starter brace on because I have 0 idea how it went on but by dumb luck I noticed the 76 already has a starter brace. I got the 76 cranking when warm but you have to hit the pedal once for it to light off. I’m just glad it’s cranking once hot.
 

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If the voltage drops show the cables to be goods, the battery is new, the last thing is the starter. When a starter tries to work in a low voltage and it's cranking too slow, it ends up compromising the connections from the brushes to armature along with overheating the windings.

Once a copper wire is overheated and it's color has changed, it's junk. It will have continuity but will not pass voltage.

I purchased a new Autozone starter for one of the trucks, worked great until I needed it to crank an extended amount to time. From that point forward, it cranked like yours when hot until I warrantied it.
 

iamtherealJayy

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Damn I really don’t want to change the starter. But I’ve got two of those mini starters would one of them work? I can get photos of them later I was going to try and use one on my 357
 

iamtherealJayy

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I went and checked my mini starters, one is a staggered bolt other straight, so I should be able to use the staggered one correct? Is the wiring the same?
 

iamtherealJayy

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Took the starter off cleaned it with brake clean reassembled, replaced missing screw and tightened another screw holding the end cap on and so far it’s working pretty well truck fired up instantly I drove it around the yard to operating temp shut it off and it fired right back up. It is still popping and making flame noises from exhaust. I’ll work on the carb tomorrow I’m moving to 76 for today. I got it cranking when warm but it won’t start without a pump of the pedal, I’m thinking idle may be too low not positive yet. It stalled when I first put it in drive earlier.
 

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Gettin' there!
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iamtherealJayy

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I’ve got both trucks cranking now, but what could be causing the 78 to suddenly run rich and pop and crackle through exhaust? I showed a video of a flame lol
And what’s up with the 76 not firing? It’ll crank and fire but if it doesn’t catch it won’t stay running and then it will crank infinity I reckon. One press of the peda and it instantly fires and is in high idle so blip throttle to return normal idle speed and it idles fine. I have not installed a tachometer yet so I’m not positive on idle speeds. I did find the timing tab on the 76 but it’s bent and flattened into the front of the block
 

iamtherealJayy

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Oh since you might not have been on any of my other threads, the 78 is a 350/sm464/np205 with an edelbrock 1405. The 76 is a 350/350/np203 with a factory quadrajet. My issue with the 78 is off idle rich black haze from exhaust fuel smell and popping/crackling. The 76 will fire up and run no issues but if you shut it off and go to start it back it instantly fires but doesn’t run on its own, if you press the pedal once it’s fires no problem and runs fine(high idle blip pedal and it runs fine) is there something in the carb that should shoot some fuel when cranking? The carb is supposedly freshly rebuilt and I have to admit it looks clean and new gaskets atleast.
 

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So on the starter thing, I believe you said your 78 is a manual right? if so you justn eed to make sure the bolt pattern is right and the flywheel and starter drive wheel have the matching teeth counts.
If you used a mini starter, I hope you used new bolts.
Also, starters on manuals bolt to bellhousing I think and automatics to the engine.


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Past that,
Your 78 sounds like timing issue to me , like r-tarded timing, have you set it back with a timing light? you said you played with it.

76 sounds like possibly a heat soak or something. Does this truck have a return line?
 

iamtherealJayy

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The 78 is a manual, the 76 is the only automatic I own. I did not change the starter as the thickness was different, I would’ve needed shorter bolts by around a half inch. The timing on the 78 is at 8° btdc mechanical advance works but I don’t think the vacuum advance is functioning. It’s not causing a vacuum leak but I don’t think it’s pulling timing.
I believe the 76 has a return line on the fuel pump but I’m not positive I’ll go look right now. Yes there’s three lines on the fuel pump. It cranks fine now but if you don’t give it one press of the pedal I guess it’ll crank infinity? I just hit the pedal once if it doesn’t instantly fire
 

AuroraGirl

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The 78 is a manual, the 76 is the only automatic I own. I did not change the starter as the thickness was different, I would’ve needed shorter bolts by around a half inch. The timing on the 78 is at 8° btdc mechanical advance works but I don’t think the vacuum advance is functioning. It’s not causing a vacuum leak but I don’t think it’s pulling timing.
I believe the 76 has a return line on the fuel pump but I’m not positive I’ll go look right now. Yes there’s three lines on the fuel pump. It cranks fine now but if you don’t give it one press of the pedal I guess it’ll crank infinity? I just hit the pedal once if it doesn’t instantly fire
if its not pulling its either incredibly not hooked up/broken or there is a vacuum leak.. lol.... the vacuum advance needs to be capped for your timing anyway

In my opinion if you have the emissions components off,desmogged that 78, you should run 10-12 advance.But that is just my opinion. it shouldnt be like crappy to great running for example. and on your fuel line situation, can you confirm that the line to the tanks (to return) is not blocked? Im surprised a 76 has return lines.. can you see between the cab and bed if the tank has 3 ports?
 

scrap--metal

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if you press the pedal once it’s fires no problem and runs fine(high idle blip pedal and it runs fine) is there something in the carb that should shoot some fuel when cranking? The carb is supposedly freshly rebuilt and I have to admit it looks clean and new gaskets atleast.
This is normal. You should always hit the pedal to set the choke on a quadrajet. That will also give it some gas before hitting the key. The carb should hold fuel between start-ups, but it can leak out of evaporate during extended periods of sitting.

There is nothing in the carb that will shoot fuel just because you hit the ignition.
 

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