"The Car, Like, Blew Up"

Turboguy

Turboguy

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That's what the wife called and said to me just as I walked into work today :mad:

Apparently the LS started, stopped, made some horrific noise, and let out a nasty smell. Kind of like what I do in the morning.

Now I get to sit here at work trying to figure out WTF she did to it. Ugh.

:(
 
So you are one of those guys that figures she had to have done something wrong for a problem to happen? Sounds like it could be as simple as a blown belt or as bad as a rod through the block. Good luck!
 
Yep Josh, she drove it the last 3 days in a row, the last time I drove it I checked fluids, looked under the hood, etc.

Of course, it might not be her fault. But she racks up wrecks and parking tickets like a pro, so blaming her is all in good fun. And she blames me for wrecking her living room with my car junk. Good times.
 
Thanks Nick. From the way she described it, I wonder if the chains went (of course, not her fault :)) I'll let you know...
 
Actually, the electronics should give some sort of warning before something catastrophic happens. Just hope for the best. Unless some warning indicators have been disabled it might be ok. Look under the hood for the belt just like Mac Mac said.
 
Thanks Robot.
Just talked to her again, she left an important part out of the first conversation. Apparently she started it up again and it idled rough (but was idling) so that's a hopeful sign. I'll go plug the scanner in tomorrow and see what we're dealing with...
 
Well, I think it's OK.

I can't blame her for thinking that it blew though: after pulling codes (have cat going otherwise clean) and checking belts, fluids, vacuum lines etc. I started it. Backfired like a mofo and idled rough. No brake pedal vacuum, either.

My layman's guess is that maybe after she's been pulling onto snowbanks to park, she smacked the exhaust/converter and something dented or broke something loose in the cat, plugging up the exhaust almost totally.

So Nick...how do your weekends look these days? :)
 
Turboguy said:
...My layman's guess is that maybe after she's been pulling onto snowbanks to park, she smacked the exhaust/converter and something dented or broke something loose in the cat, plugging up the exhaust almost totally...
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I don't blame you for that hope, but it sounds more like a timing chain skipped to me.
 
Turboguy said:
Ugh, that's not what I was hoping to hear joe...Damn. Guess it's time to tear into the old girl...
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Well, you can remove the front two O2 sensors as a test. If it will idle okay with those removed (to reduce exhaust back pressure), then your theory is probably correct. If it makes no difference, you can rule out exhaust blockage.
 
sounds like timing chain. its acting like the one i fixed a skipped secondary chain on.
 
Update: Back of intake blew off. Reasons???

Just heard from my crack LS mechanic Nick.

The back of the intake manifold blew off, which is why it ran like crap, smoked, died, was loud as hell, and had no brake vacuum.

That answers one question. Now comes the why. I know one of my cats is bad so it has been running richer than it should.

Any of you had this happen to your V-8 LS? Did you find a cause, or was it just a bad backfire?
 
Fixed!

Well, here's the original intake with the back blown off. Don't know the whys or hows, but found a used manifold on ebay for $125 and it's running like a top again, thanks Nick!

I know one cat is plugged, so gonna take the opportunity to swap in new cats, ball joints, and tie rods.

Boom1.jpg
 
That's crazy! I'd be looking deeper into that for sure.

A clogged cat could cause more back pressure, but it usually just clogs the air flow causing stalling etc due to poor scavenging of the cylinders.

The only thing I could think of is somehow the combustion or exhaust gases blew by an intake valve.

Unless joegr or someone with more mechanical experience can say, I'd be doing a compression, or leakdown (more preferable) to make sure one of your intake valves isn't leaking. Either that or your getting preignition going on via carbon or timing. Those are the only things I can think of.

Either way, this issue needs to be solved or else I have two intakes I can spare for a nominal fee ;)
 
It's easy for combustible gasses to get into the intake manifold. If nothing else, the PCV system can deliver this. To me, the real question is what was the ignition source?
 
joegr said:
It's easy for combustible gasses to get into the intake manifold. If nothing else, the PCV system can deliver this. To me, the real question is what was the ignition source?
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I thought about that, but I would think it's hard for that much combustion gas to make it all the way through the crankcase to the valve cover, and back through again. I could see an issue if the PCV system failed, but beings the V8 is simply a tube, I don't see how that could be. I think the V6 would be more prone to something like this.

What if the PCV was clogged? That would cause pressure build up in the crankcase correct? Again, I would think unlikely since ours is a pretty wide-opened hose.
 
A clogged PCV tube could cause pressure build up in the crankcase, but I don't see how it could in the intake manifold.

I have seen that the intake manifold can have a pool of oil in the bottom of it [I assume] from the PCV system. I've seen this on my 04, and other members have seen this. A pool of oil would have combustible vapors over it. Of course, I don't know if that was the case here. (Note that my 04 is not consuming a noticeable amount of oil between 5K oil changes. It could be up to 1/2 quart short, but I think it is less than that.)
 
When I put the new/used intake i got as much oil out of it as I could before installing it. I took a fuel pressure test over about a 2 hour period and compared it to my car and readings are very similar so I dont think there is a injector leaking even though it does not settle in the intake figured I would check. So far car is running ok, only drove it 5 miles. After putting cats on it this weekend I will have a little more confidence to drive it more, I could see a lean condition doing it also, would have to drive it for a period of time and see if fuel pressure drops off after pump is running a while. Hopefully dont find out by blowing another intake.
 
Yeah, it was pretty wild. Thanks for the responses, it's in good hands now so we'll just have to see...I'll post an update once it's back from Nick.
 
joegr said:
A clogged PCV tube could cause pressure build up in the crankcase, but I don't see how it could in the intake manifold.

I have seen that the intake manifold can have a pool of oil in the bottom of it [I assume] from the PCV system. I've seen this on my 04, and other members have seen this. A pool of oil would have combustible vapors over it. Of course, I don't know if that was the case here. (Note that my 04 is not consuming a noticeable amount of oil between 5K oil changes. It could be up to 1/2 quart short, but I think it is less than that.)
Click to expand...

We're talking oil going from the valve cover tube, to intake, through the throttle body and to the bottom of the intake manifold correct?

If so, that would be alott of oil to have enough combustibal properties to do damage like that
 
Broseph said:
We're talking oil going from the valve cover tube, to intake, through the throttle body and to the bottom of the intake manifold correct?

If so, that would be alott of oil to have enough combustibal properties to do damage like that
Click to expand...

Yes, that it's due to oil in the intake manifold is a long shot, but I do know that oil can be sitting there. I've seen it.

As for the source of the explosion, I have no other guesses, but I wouldn't place any bets on the one that I have presented.
 
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