LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

Huge bang and now the car barely drives

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Old Nov 30, 2006 | 09:58 PM
  #1  
jjminch's Avatar
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Huge bang and now the car barely drives

I've been having a high rpm miss since my header install. I was getting a random misfire code from this. Traced it down to a burnt plug wire (thanks for the suggestion) and I replaced the wire and the plug.

Everything seemed to be running fine since then. Still had a high rpm miss above 5700 rpm. But I figured that was the stock opti, which may or may not be original.

So I was driving to work today and gave it some WOT to pass someone. The car was running hard up to redline and then BANG! A large explosion, sounded like a backfire. Not sure if this was from me but I saw some debris fly out behind me. I thought the exhaust broke, but that wasn't the case. I have no idea what flew off and probably never will.

Afterwords the car had no power, and still doesn't. It idles great. But when you give it throttle it just sputters forward and surges. It's really rough and drives horrible. I really hope I can make it home.
Old Nov 30, 2006 | 10:38 PM
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that happened to me a while back and it turned out being the intake elbow had poped off and it was sucking in air without going through the maf and it backfired and had no power so i would check that
Old Nov 30, 2006 | 11:46 PM
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Originally Posted by slowz2895
that happened to me a while back and it turned out being the intake elbow had poped off and it was sucking in air without going through the maf and it backfired and had no power so i would check that
wow that sux! lol
Old Nov 30, 2006 | 11:52 PM
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20 bucks says that you were running lean and finally blew a piston apart.
Old Dec 1, 2006 | 12:06 AM
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I'll go check the intake assembly now. I don't think I blew a piston though becuase it idles fine without making any noises. If I had blown a piston it would be making one hell of a racket.
Old Dec 1, 2006 | 01:37 AM
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With EFI motors, you can burn holes through pistons, shatter ring lands, seize rings to the lands, etc and the motor will still idle just fine, have seen it many times.
Old Dec 1, 2006 | 03:11 AM
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Intake assembly is in place and no problems. I just found I have a fuel leak from my filter. I just swapped it out today and then test drove it. No problems then. I'm going to get the leak tightened up and see how it goes from there.
Old Dec 1, 2006 | 11:30 AM
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Originally Posted by jjminch
Still had a high rpm miss above 5700 rpm. But I figured that was the stock opti, which may or may not be original.
Rev limiter is set to 5850 stock... thats probably your miss above 5700
Old Dec 2, 2006 | 11:46 PM
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Well I found a missing header bolt, so maybe that was what caused it. I pulled the plug below it and it's got a lot of oil on it. So it looks like I gotta learn how to do head gaskets.

On the bright side I got a new opti distributor and coil from $60! I'm going to ahead and swap them soon.
Old Dec 3, 2006 | 11:23 AM
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Originally Posted by jjminch
I pulled the plug below it and it's got a lot of oil on it. So it looks like I gotta learn how to do head gaskets.
Oil on the plug is not a headgasket issue, it's a ring/piston, valve guide problem.
Old Dec 3, 2006 | 11:35 AM
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yeah this reads like it isn't going to be good... big "BANGS" in the engine bay are never a good sign of anything.
Old Dec 3, 2006 | 08:36 PM
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Thanks for the replies. Help me out here I'm a newb when it comes to engine internals. So since I have oil on my piston it means I have a bad ring around that piston? Can I fix this with the motor still in the car? IE I take off the heads and intake and then replace the pistons and valves? Or will I basically need a new shortblock with new rings pistons, and everything?

Thanks guys. This flat out sucks. I've had the car for less than two months and I don't have the money for this.

I already got a new opti and a coil, because someone that it was an ignition coil. That's what I thought until I saw the oil soaked plug. Anyone have a shortblock they want to donate?
Old Dec 3, 2006 | 08:41 PM
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Originally Posted by jjminch
Thanks for the replies. Help me out here I'm a newb when it comes to engine internals. So since I have oil on my piston it means I have a bad ring around that piston? Can I fix this with the motor still in the car? IE I take off the heads and intake and then replace the pistons and valves? Or will I basically need a new shortblock with new rings pistons, and everything?

Thanks guys. This flat out sucks. I've had the car for less than two months and I don't have the money for this.

I already got a new opti and a coil, because someone that it was an ignition coil. That's what I thought until I saw the oil soaked plug. Anyone have a shortblock they want to donate?
The only way to see if the piston is trashed, is A) you have a small lighted camera that can fit in the spark plug hole to look, or like most people B) you pull the head on that side to check the piston. And no you cant fix it with the motor in the car.
Old Dec 3, 2006 | 10:05 PM
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does the car smoke out the exhaust at all? Oil on the plug could be piston rings or valve seals or very very unlikely a cracked block but since LT1 have iron blocks I would venture to say really really really really really really really unlikely
Old Dec 3, 2006 | 10:43 PM
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Well it smokes a little but only since the header install. Since I deleted the cats I thought this was the reason why it was smoking.

Anyone have any luck with those Bar's Stop leaks? I still have to drive this car, I don't really have a choice. Maybe if I throw some of that in there I can still get a few months without the engine seizing?



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