New engine starting issues

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Penstarpurist

Penstarpurist

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Finally got to the point where we are trying to start our new engine to break it in, it starts for a few seconds and then dies. Turns over strong, starts up again and dies. Everything is new, from carb to pan, timing appears to be dead on, no backfire or sputtering. Good spark, strong fuel flow, definitely good compression. Checked the cap to plug wiring routing and it’s correct, set engine to top dead center, rotor is pointing at #1 when it fires up at first it runs strong then acts as if it’s starving for fuel, but it’s getting good fuel flow. Unhooked the fuel line and ran it into a bottle and it’s definitely there. Good fuel spray from the carb into the intake. Just need some fresh input as to what to try as we don’t want to wipe out the cam cranking it over and over. Thanks in advance.
 
FYI engine is in a 1971 valiant 318 aluminum heads, intake and avs 600 cfm carb, .40 over bore.
 
Penstarpurist said:
Finally got to the point where we are trying to start our new engine to break it in, it starts for a few seconds and then dies. Turns over strong, starts up again and dies. Everything is new, from carb to pan, timing appears to be dead on, no backfire or sputtering. Good spark, strong fuel flow, definitely good compression. Checked the cap to plug wiring routing and it’s correct, set engine to top dead center, rotor is pointing at #1 when it fires up at first it runs strong then acts as if it’s starving for fuel, but it’s getting good fuel flow. Unhooked the fuel line and ran it into a bottle and it’s definitely there. Good fuel spray from the carb into the intake. Just need some fresh input as to what to try as we don’t want to wipe out the cam cranking it over and over. Thanks in advance.
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Verify that you have power to the coil with the key in the ‘run’ position.
You may have power to the coil with the key in the ‘start’ position, so the engine starts, but when the key is released to the ‘run’ position the power is disrupted due to a wiring fault or a defective resistor.
 
my68barracuda said:
Verify that you have power to the coil with the key in the ‘run’ position.
You may have power to the coil with the key in the ‘start’ position, so the engine starts, but when the key is released to the ‘run’ position the power is disrupted due to a wiring fault or a defective resistor.[/QUOTE/]
I will definitely check that. If that’s a problem could I bypass the resistor to test that? We did put in a new engine bay wiring harness as well as a new resistor. But that said I have seen electrical parts bad out of the box.
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Sounds like ignition related. Read this article.
 

Attachments

  • ROAD SIDE TROUBLE SHOOTIMG GUIDE 1 (2).pdf
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Maybe jets are clogged up in the carb? Stuck needles in float bowls?
 
To rule out the ignition you could trickle fuel into the carb while it is running. If it keeps running it's the carb or fuel pump etc
 
Get a clear fuel filter to see if fuel is going to the carb. Maybe get a fuel can run the hose from the fuel pump straight to the fuel can
 
If it is a points dist, make sure the gap has not closed up.
 
Penstarpurist said:
Finally got to the point where we are trying to start our new engine to break it in, it starts for a few seconds and then dies. Turns over strong, starts up again and dies. Everything is new, from carb to pan, timing appears to be dead on, no backfire or sputtering. Good spark, strong fuel flow, definitely good compression. Checked the cap to plug wiring routing and it’s correct, set engine to top dead center, rotor is pointing at #1 when it fires up at first it runs strong then acts as if it’s starving for fuel, but it’s getting good fuel flow. Unhooked the fuel line and ran it into a bottle and it’s definitely there. Good fuel spray from the carb into the intake. Just need some fresh input as to what to try as we don’t want to wipe out the cam cranking it over and over. Thanks in advance.
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Ignition: Check all your ignition wiring, especially the ground connections. Connect a voltmeter to the coil and monitor the voltage.
Fuel: idle speed high enough? Idle mixture screws out about 1-1/2 turns “as a starting point”? Insured idle circuit passages are clear, not plugged?
 
MOPAROFFICIAL said:
Then you're the care taker of this thread. Good luck
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Nope, but I too have not read an entire thread and ended up repeating a suggestion that was already said.

I was just pointing out that your suggestion, which by the way is spot on, way already tried.

Did not mean to ruffle any feathers.

Merry Christmas
 
"Unwire" the ignition system AKA isolate it from the harness. WHAT IGNITION system are you running? Hot wire it to eliminate various harness/ connector/ switch problems

You might consider eliminating the fuel system by plugging it, and running a hose from a siphon/ gravity feed container above the carb direct to the carb fuel inlet

It may be a timing/ carb/ throttle position issue, AKA the throttle blades may be out of the transfer slots. Where is the timing set? If you have a "hot" cam and the timing is less than say, 15* initial --you need to bump it up

Crank the idle screws out some at least 'til it's warmed

Check for vacuum leaks
 
Well it was a bunch of little things all related to the coil, distributor and the ballast resistor. The ballast while new had a small crack, the new msd coil wasn’t putting out enough volts(put the old one on and put it up from 3.5 to 5 with key on) then even though the internals had all been replaced in the distributor it just wouldn’t keep spark going to the engine once the key was fro start to run. Replaced it with a new drop in ready unit and it fired right up. Thank you so much to everyone that commented on it and all the great advice. Ran it for the break in and it’s idling very nice and starts right up every time.
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If I can figure out how to post a video of it idling I absolutely will.
 
Dana67Dart said:
Nope, but I too have not read an entire thread and ended up repeating a suggestion that was already said.

I was just pointing out that your suggestion, which by the way is spot on, way already tried.

Did not mean to ruffle any feathers.

Merry Christmas
Click to expand...

Not ruffled at all.. yes I only skimmed through after reading the opener and just gave my advice on what I'd start with perhaps..Though I've encountered people seemingly claiming threads or oddly enough refereeing them. I look at it like this... sometimes OP's reading responses echoed pushes/reassures them to proceed.. if say.. they weren't convinced enough hearing it 1st ,2nd or 3rd time. Lol

We've had op's ponder from the front to the rear bumper 4 pages and yet not go through the basic page or two of advice and try it.
 
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