I know many of us have gutted the converter on our cars. What are some steps you need to take along with that to prevent running poorly? What types of symptoms do you normally see?

 

Nothing really.
Cars of this age do not use post cat 02 sensors so you get no codes.
And even then running no cat or gutting it affects anything as far as its running, just the air gets affected!

 

What about back pressure?

 

Yes is lowers back pressure and thats why people do it, to add some performance by it being lowered.
Does not affect how the car runs in anything negative other than emissions output rises.

 

Re: The TBI glitch that I can't fix
Quote:
Originally Posted by cal30_sniper
Will definitely check the timing this weekend. I wouldn't think it would be the fuel pressure, as the problem would only get worse as I went further down with the throttle, not better.

Unplug and block the EGR hose to the EGR valve. See if your problem goes away. If it does, install an EGR valve for a TBI 305/350 truck. The stock L03 car EGR valve relies on exhaust backpressure to keep it closed. Truck EGR setups require backpressure to OPEN. You have taken the backpressure away from your exhaust system which allows your stock EGR valve to flop right open. That is the difference between positive and negative backpressure EGR valves.

This statement was made on another thread. I always thought that engines needed a certain amount of back pressure to operate properly, but I didn't know how much. Given that this is the first time I have gutted a converter, I have no history to go by. I thought I might get the thoughts of my fellow 3rdGenners.

 

Just gutting a cat doesn't affect the back pressure as much as your thinking, having a bunch of big pipes straight out the heads is bad because of not enough pressure, but having a full exhaust out the back with headers and a gutted cat is perfectly fine

 

I was hoping that is okay since I already did it! Just trying to chase down an idle stumble and poor high rpm performance.