My 91 is Knocking, Fuel Injection and Catalytic Converters

[MikeYESfan]

Hi All, This 1991 is my 1st Vette, so this means I know Nothing about this Car. I kinda knew it had Fuel injecter problems when i Purchased the car but did Not test drive it enough to get the car Hot and hear this Knocking noise.

So far It run Great, but I only have put a few hundred miles on it.
The car runs fine but when you stop and Idle, it sounds like a LOUD Knocking Sound. If you increase the Idle a little the Knock goes away. It's coming from both sides of the car where the Catalytic converters
Are. It also gets Real Hot..You can feel the heat in the Car and especialy when you park.
I was Told that the Cat converters were blown out and that was because of the Fuel injection problem.
Tommarrow I'm headed to Long Island to see the Vette Show at Ramp Chevy, and was hoping to get some answers.
I do want to see the C6....
Thanks
Mike

 

[Moonunit 451]

Welcome Mike, but this doesn't sound good Give us a LOT more info on the car, and don't drive it too far without AAA Plus. Give ALL detals you can think of.

 

[virdtoy]

knock,knock

sounds like u have a bad pre-cat, i had the same problem thought it was the injectors. the mechanic told me the rod bearings were bad,and wanted to replace the engine. check out your cats first.

 

[Hib Halverson]

It is possible that the rattle you hear at idle is the cats. One type of cat failure has the substrate breaking-up and the rattling you hear might be chunks of substrate rattling around in the shells of your pup cats.

Cat failure is caused by a varitey of problems. One can be overly-rich fuel mixture causing the cats to get too hot and their substrates melting or disintegrating. The overly rich AFR can be caused by a fuel injection problem.

Taking the car to your service facility for a "check-up" is a good idea and one thing you could have them do is simply remove the pup cats and leave the main cat in place. You'll get rid of the damaged cats and gain a little power due to the decreased restriction.

At the same time, fix the problem with the injection that took out the pups or it may take out your main cat, next.

 

[MikeYESfan]

It is possible that the rattle you hear at idle is the cats. One type of cat failure has the substrate breaking-up and the rattling you hear might be chunks of substrate rattling around in the shells of your pup cats.

Cat failure is caused by a varitey of problems. One can be overly-rich fuel mixture causing the cats to get too hot and their substrates melting or disintegrating. The overly rich AFR can be caused by a fuel injection problem.

Taking the car to your service facility for a "check-up" is a good idea and one thing you could have them do is simply remove the pup cats and leave the main cat in place. You'll get rid of the damaged cats and gain a little power due to the decreased restriction.

At the same time, fix the problem with the injection that took out the pups or it may take out your main cat, next.

Thanks, I was at the Corvette Show at Ramp Chevrolet. I will bring it to Ramp Chevy on Long Island to Check it out.