94TA25ann

I finaly got my 3.73's broke in and decide to take itfor a spin on my lunch break at work. I gunned it at the light and took her up to about 70 shifting at 6200. When I came to the next light the car shut off, which I figured was a uel pump problem or maybe the coil wire came loose. Well I started the car and it had a loud knock to it which was clearly audible over my true duals. I drove it about 100 feet to a parking lot and let it sit till the next day. That day I pulled both valve covers and inspected the valve train and everything was working properly. I figured it was time for a rebuild, until my neighbor who is a mechanic said it might be a piece of carbon buildup making the noise(this is not my daily driver and have only put 9000 miles on it in 2.5 years). He siad to find the vacuum line and dip it into a glass of water to steam clean the cylinders out.

I wanted to get your opinions because my car runs normal besides the knocking sound, has the same oil pressure as before, and has no metal shavings in the oil.

Also, where and which vacuum line would I pull to dip into water?

shoebox

Never have heard of any carbon causing a sound that could be mistaken for a rod knock. If it sounds like a rod knock, it probably is. You might not have metal particles you can find now, but you will later.

rngilliland

I've had a piece of carbon on a piston make a loud knocking noise before. I haven't seen it on a fuel injected car though. We used to fix it by pouring transmission fluid in the carb with the engine running. I would give the water trick a try. It shouldn't hurt anything and might fix your problem.

LT4orbust

do you know how to float the rpm around 2000 rpm and ck for rod knock, slightly move the rpm just above and below 2000 rpm , a rod will knock as the rpm drops.

94TA25ann

It knocks no matter what RPM your at, and it doesn't matter if the car is cold or not, it still knocks.

94TA25ann

What parts (crank, rods, pistons, rings, bearings) should I go with. I plan on getting the LE2 pkg and want my bottom end to be able to spin high without spinning rod and main bearings. I already plan on my car sitting for a while and I'm willing to put about 3000 possibly 3500 towards a shortblock rebuild.

List me some engine combos and prices. Also, I wouldn't mind running a 100-150 shot of nitrous sometimes.

Jon

Cmr0z28

My car was making a knocking sound and had sufficient oil pressure, etc just like you're describing.

Wanna see what my flexplate looked like?

http://img.photobucket.com/albums/v4...8/DSC02976.jpg

94TA25ann

I treat my car so well. It's hard to believe that it would have a rod knock, but I guess it happens to the best of us.

LT4orbust

You have a manual trans right, no flexplate.
Anyways how loud is it? was the trans out lately, maybe loose bolts on the flywheel , if it's there all the time it must really be loud, it sounds like more than just a worn bearing... maybe a fractured piston

94TA25ann

No, I have an A4. My car is pretty loud with the true duals and the knocking is louder than the exhaust. I just don't understand why the car doesn't idle messed up or something. If it had a fractured piston wouldn't it run terrible? I haven't driven the car because I'm afraid of screwing my motor up.

LT4orbust

shifting at6200 i figured it was manual, a flexplate can sound like a rod knock, for it to happen all at once, it could be a flexplate, bearings usually come in slower

94TA25ann

I wonder if my flexplate is cracked. It is the first time I hammered it from a stop since getting my 3.73's installed. I wonder if the combination of my Nitto 305/35/18 DR's and my 3.73's could have cracked my flexplate?

30696bird

It's something to check, the reason I have a hard time believing it's a bearing is because of the oil pressure. I know when I spun my bearings (ALOT of them because I drove 50 miles after it happened ) I had 0 oil pressure and the car shut down from the heat. I waited about 15-20 minutes, it started right up and I drove it to a friends house. Went back the next day, WHILE COLD it had GREAT oil pressure (40-45) and as it warmed up it got worse. Point being, when cold oil pressure may be fine but as it warms up.......it'll drop.

shoebox

When I spun a bearing, my oil pressure never changed.

94TA25ann

I'm going to check it out today and see what I find.