Box of Rocks

Hi guys,

I'm baaaaack. Been busier than a cat covering up doo-doo lately.

Speaking of cats........

My buddy has a 1989 Corvette (I know, please hold the ration of shizz) with a problem. Maybe one of you has some exposure to these symptoms:

After jumping on it and running it up through the gears, he has a dramatic loss in power (but it runs on all eight) and a NASTY noise coming from the oil pan / exhaust area.

Here's the weird part: it only makes ugly noises when you let off the accelerator. It sounds like a Box of Rocks (no, not me....the car) in a Folger's can.

Very ugly - like a metal-to-metal contact sound that is commonly heard just before a motor grenades.

He says he did not wing the engine past 5,000 RPM, but it is a 130K motor, so who knows.

I say it's one of 2 things:

1)A piece of cat gut has broken loose, lodging itself in the innards so as to block exhaust flow and also rattle around like crazy on deceleration.

2)The 'Vette may have a baffled oil pan, and said baffle could have come loose. The crankcase has to breathe thru a relief somewhere down there, and the baffle may be obstructing the relief. I pulled the PCV, and found no blowby thru the valve cover hole. This whole idea seems a tad farfetched, but hey, it's the weird ones we correctly diagnose that separate 3rd Gen men from the boys, right ?

So, do we think it's de cat ? De mouse?

Oh, I'm officially a published author. An article entitled "Is there a barcode for a 400-pound Gorilla ?" appears in the spring edition of Parcel Shipping and Distribution magazine.

No, I did not write anything concerning the "POOTERBALL" episodes, although if you want some entertainment from some overly-tired engineering types, try searching this site under the words "Pooterball" and "BOR".

Now THAT'S interesting reading. Vader - you about ready for another moonshot ? If so, I'll call the sidewinder so we can stir up a fresh batch.

Thanks in advance for the help guys.

BOR

[This message has been edited by Box of Rocks (edited May 18, 2001).]

ws6transam

Sorry BOR, ya got me "Baffled"!

It seems to me that if its the cat breaking up, you'd hear the nasty noise when you first start up the car, when the exhaust system is cold.

I guess I'd yank off the exhaust and check, and if nothing was obvious, I'd then proceed to yank out the motor and pop off the oil pan to see what's in there. My dad once found an extra bolt in the oilpan of his 350 Chevy Suburban...

ede

is the exhaust pipe double wall? i've saw the inner wall delaminate and make noise or collaspe and cause power lose.

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ICON Motorsports

1st & 3rd
MM Black Diamond 538 F&AM

IrocLouver

I had this experience two weeks ago. Started with a small tick, and two days later it was a golf ball in a coffee can. Mine was most noticable when barely on the gas. Under hard acceleration I guess it was pinned against the back of the can. I confirmed my diagnosis by giving the cat a good rap with my hand and sure enough you could hear the chunk rattling around in the inboard cat (2-cat system).

Bort62

Ive got the Same deal, On a 6 onth old 3" hi Flow.

Im pretty sure I have somethig Loose in the exhuast. Its entirely possible that a bolt fell down the Ypipe when I had the Motor out, tho.

haha

My car seems like its getting slower, Too ( Maybe its me ? )

So Im suspect that Running rich and without and AIR pump has toasted my cat. Time to cut er out.



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60 Ranchero - Project ( Money Hole )
85 Sport Coupe LG4 - Daily Driver
Reader's ride -> My Ride

Just another Hot Rod kid, or thats what they all tell me.
Livin' the Stereotype

jaretz28

Your #1 guess happened to me last November. It was my cat. So I left it a just got all new exhaust. But it can happen.

Matt87GTA

Well in reading your comments I see that you say it sounds like the sound a motor makes just before it grenades so I will guess that the engine is about to expell some internals just to prepare you for that if it happens .

Laterzzzzzzzzzzzzzzz

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Matt

1987 GTA L98 MD8 GW6

"Stop Lights timed for 35Mph are also timed for 70Mph"

Box of Rocks

Thanks guys.

The car checked at Midas ( $15 ) with both pre-cats bad and the main cat bad.

We've found a guy that will install a Y pipe and new hipo cat for $400, so my buddy is going that way.

I wonder how many guys have sold cars for fear they were about to grenade when it was only a bad cat.

Darned house pets, next thing you know it will pee on the carpet.

Thanks again guys !


BOR