Need alot of help quick!

[94 formula]

I was driving home from my girlfriends tonight and my car started knocking bad. Its knocked once in a while I figured opti or plugs but it was never bad I just got plugs to change them (98,000 miles) and am planning soon but tonight I started loosing power and it sounded like the 3rd or 4th cylinder back on the pasengers side was not firing at all. I was only about 2 miles from home so I figured that I could limp it home I didn't make it far and heard a horrible hissing sound I pulled over poped the hood and the manifolds on the pasenger side were orange they were so hot. I'm guessing it wasn't burning the gas at all and when it hit the hot manifolds it was detonating. Now I can hear air leaking out when its running (I let the engine cool then limped it home). I'm hoping that I just blew the gasket for the manifolds or cracked the manifold and didn't crack the head. I know with aluminum sometimes it doesn't take much for them to go. Has anyone else had this happen would the manifold go first? If it is the head is it repariable at all or do I need a new head?

[FRMLAV8]

Normally when that happens (overheating), it will blow the head gasket. If it didn't blow it, it is going to.

But definitely sounds like the gas wasn't combusting, or the fuel injector wasn't firing.

That happened to a friend of mine - Inj. stopped working, cylinder overheated, and his piston shattered.

Definitely have the motor checked out. Probably want to do a leakdown test and compression test.

[N20LT4Bird]

gotta tell us what kinf of car you're dealing with.

[jim97ss]

Sounds like your catalytic converter could be blocked.

[FRMLAV8]

If the cat was blocked wouldn't both sets of manifolds be overheating? I have never ahd that happen so I don't know, so I am just guessing there.

Randy

[94 formula]

I'm talking about my 94 firebird formula. Its not the cat the overheating was caused by a cylinder not firing and when the gas that wasn't detonated hit the hot manifold it combusted i'm wondering what i'm looking at for repairs?

[Joe 1320]

Nobody can tell how much it's going to cost without more diagnostics. A leakdown test and compression test will be a must in order to find out what's happening inside.

[hotwhip9]

i feel the pain. Something similar happend to my z a while back, had to have the motor checked out, and what happened was a rod bearing went which in turn messed up a lot of components. 4000 later, i have a rebuilt ls1 with only 600 miles in it now, because im in Iraq and haven't even driven it yet! Its sad! it was driven home by my father after i was already overseas and says it runs fine now though, it better or ill be mad. But the knocking noise your talking about is what mine was doing. then it would get quite for a second then really loud, sounded like 2 peices of metal being beaten against each other.

[94 formula]

Just got back from working on my car. I just figured I'd get the new plugs and opti out of the way that was a pain. Tommorow the manifold is gonna come off. I'm thinking theres a crack in the manifold (hoping its not more). If its not to bad I'll just drill a hole at both ends of the crack and try welding it if that doesn't hold up time for a set of headers. I had it running for a little bit just by sound I think that the 3rd or 4th cylinder wasn't detonating and the gas was going off when it hit the hot manifold. I'm really not sure if thats the problem but I'm hoping its not a cracked head or something down in I guess I'll find out tommorow.

[N20LT4Bird]

Originally posted by Joe 1320
Nobody can tell how much it's going to cost without more diagnostics. A leakdown test and compression test will be a must in order to find out what's happening inside.

I'd listen to Joe before I started ripping and tearing. Those 2 tests are easy and will tell you a lot about the internals.

[94 formula]

What is the leakdown test? lol I thought I knew a bit about cars but I've never even heard about a leakdown test. I'm gonna pull the manifold off, tried today but need some different tools. It made a loud pop and a hiss when it went. The tube that runs up from the crank (something with the emissions) was horribly burnt and you can see where its blew out the side. I'll do the tests to save any trouble but I'm 90% sure that theres a crack in the manifold and the engines ok but I'm not positive.