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Intake exploded on startup

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Old Apr 27, 2024 | 07:24 PM
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Default Intake exploded on startup

Well today is a bad day to say the least. Cars been on jackstands since January doing a auto swap. So I been trying to figure out the wiring on the Nss switch to start the darn thing without having to zip tie the clutch switch ,one thing I didn't think of and i dont know if it adds fuel every time you push the button and it doesn't crank or what ? Anyhow I couldn't figure out the wiring to make the nss work ,so I zip tied it . then go to start it ,Bang like a 12 gauge going off. Havnt taken it apart yet,throttle body still works fine ,opens and closes doesn't look to be damaged. My thoughts on the cause - either excess fuel injected into the intake from about 5 pushbutton start attempts or intake valve stuck open ?

Thoughts ?
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Old Apr 27, 2024 | 08:28 PM
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No nitrous involved?
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Old Apr 27, 2024 | 08:31 PM
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No nitrous ,its NA ,decent sized cam with overlap
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Old Apr 27, 2024 | 08:39 PM
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I wouldn't think the injectors would fire if the engine wasn't turning over. Damn, bad day is an understatement. Hope you get it figured out.
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Old Apr 27, 2024 | 08:49 PM
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This is also a modified msd,shortened runners ,accepts a 112 TB so not cheap ,sucks big time
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Old Apr 27, 2024 | 09:13 PM
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I haven't seen an msd popped before well done! I don't think the clutch switch or push button would have anything to do with that. Intake back fire, ignition to early (bad timing) or yeah intake valve open.
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Old Apr 28, 2024 | 11:02 AM
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Man I hope its just ignition then I can just adjust that on startup,gonna take it apart today ,leave the injectors and full rails in ,test for leakdown ,if it sprays right ,with the manifold unbolted from car. Then check all the valves ,my year will be shot if I gotta take the heads off. They are mast 305's about 7 seasons on them
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Old Apr 29, 2024 | 09:34 PM
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So far valvetrain looks good ,still gotta pull off the other valve cover, getting a borescope to make sure nothing got into the cylinders. Gonna back off the ignition timing a little bit too be safe.but its not far from stock values, I did notice the #2 injector O ring seal on the msd is torn ,I can see how that could inject fuel into the intake. And the front its where most of the carnage is on the intake. Spray pattern is good on the injectors,no leakdown. Also I found a ls7 msd on ebay ,new never mounted for 700 bucks so that helps
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Old Apr 30, 2024 | 12:08 PM
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Originally Posted by Heathmb
So far valvetrain looks good ,still gotta pull off the other valve cover, getting a borescope to make sure nothing got into the cylinders. Gonna back off the ignition timing a little bit too be safe.but its not far from stock values, I did notice the #2 injector O ring seal on the msd is torn ,I can see how that could inject fuel into the intake. And the front its where most of the carnage is on the intake. Spray pattern is good on the injectors,no leakdown. Also I found a ls7 msd on ebay ,new never mounted for 700 bucks so that helps
also unless your just ultra determined i think its time to get professional help
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