HELP Holley super Sniper 4 bbl woes, 502 ci big Block

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Vbb199

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So, I've been having issues with my 502, getting it fired up.
I will try to give a short overview of what all has been done.

The CTS is ran into the intake, the O2 is at the correct length away from the collectors (weld in bung), the trucks 12v iginiton is ran to the HEI distributor. The holley is wired directly to the battery as instructed, I also have a almost virgin deep cycle marine battery to feed it.

I'm running a acdelco EP381 for my fuel pump, in line on the correct sending unit.

I have checked my base timing, reset it myself, as the engine's documentation requested, 10° BTDC,

I DID make sure the spark plug Hole was blowing out air, rolled the crank a bit further until I reached 10 degrees "BTC" labeled on the balancer, made sure my Dizzy was pointing at cyl #1, as well as the caps #1 tower was pointed at the same place.

I know without a doubt it's at a reasonable place to at least fire up.

I took my fuel gauge, and verified was getting a well primed 60 pounds of fuel (per the efi booklet), but I will add, when turning the key to make it prime the 60, the pump would make a slurp noise and kinda drop pressure on its way up to 60.

Regardless, it does create 60 AFTER the fuel filter. (also brand new, K&N brand)

No matter what I've done, motor rolls over, won't fire up, if I try to give it gas, it spits back thru the throttle body.

I'm at a loss as to what to do.

I do the setup wizard, select the 4 barrel super sniper, coil negative setup, 502 displacement, 8 cylinders, naturally aspirated.

No luck whatsoever.

I need help!

I even tried turning off fuel learning, and put the O2 in an open loop, as well as coolant temp sensor readings, with no success.

I honestly am stumped at this point.


Can someone please help me?????
 

Vbb199

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Target AFR was set at 13.5 I think.

Because it's just a GM HEI dizzy, the sniper is NOT controlling timing.

I have vacuum advance capped off as well, per the engine's instructions.
 

Poppy 87

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Are you sure that you are getting spark? Sounds like you have fuel and compression "close enough" to start. I'd go ignition diagnosis next. Good luck

Sent from my XT1254 using Tapatalk
 

Vbb199

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I got to piecing together everything that's happened today.

I recall hearing a popping noise occasionally while cranking (loud arcing)

Towards the end of the day, when I was resetting timing to put my mind at ease, I noticed one of the wires had a small crack in the shielding.

Upon pulling the plugs to roll the motor manually over to TDC, 4 smelled like raw fuel, the other 4 looked like they had a heat cycle or 2 on them.

Putting this all together now that I'm not in a frenzy and thinking more clearly, I think some of the plug wires were arcing over to the block and not actually sending spark to the plugs..

I'm gonna inspect all the wires really really good tomorrow.

Not to mention, the wires have all the nice little guides on them, plugs could've been arcing over to one another.
 

Frankenchevy

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I got to piecing together everything that's happened today.

I recall hearing a popping noise occasionally while cranking (loud arcing)

Towards the end of the day, when I was resetting timing to put my mind at ease, I noticed one of the wires had a small crack in the shielding.

Upon pulling the plugs to roll the motor manually over to TDC, 4 smelled like raw fuel, the other 4 looked like they had a heat cycle or 2 on them.

Putting this all together now that I'm not in a frenzy and thinking more clearly, I think some of the plug wires were arcing over to the block and not actually sending spark to the plugs..

I'm gonna inspect all the wires really really good tomorrow.

Not to mention, the wires have all the nice little guides on them, plugs could've been arcing over to one another.
or in the dark tonight with a family member cranking it
 

Old77

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Maybe @bluex can help? He’s got some Holley efi experience....
 

Frankenchevy

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It sounds like you have a handle on it. I had to set my crank at 50*, but mine was with timing control.
 

Vbb199

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Only person next week who could even help is my wife.
Which she said she'd turn the key for me while I look under the hood and test some things.
 
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Make sure you are not 180 degrees off on the timing . I done this many of times
 

Vbb199

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Make sure you are not 180 degrees off on the timing . I done this many of times

Man, I see you reading threads all the time, but never comment! Welcome lurker! Lol just kidding!!!

No sir, I'm not 180 off, I rolled the motor over manually until it was blowing air out of the #1 sparkplug hole. Stuck a screwdriver in there, slowly rolled the crank until I saw the handle start lifting, removed it, then continued rolling the crank until the dampener read 10 degrees BTC on it.
 

bucket

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It happens to the best of us from time to time. You are 110% sure it's not 180* out... but then it turns out to be 180* out, lol.
 

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