Wondering if anyone can help.

I have a 1992 Camaro Z28 with a rebuilt (rebuilt 2 years ago) L98 engine (5.7L V8 350 TPI, mild cam, 1.7ratio rockers, custom chip, TES edelbrock headers.

I've had this problem ever since I got the got the car in 1998. The engine was rebuilt in 2008 and assumed it would fix it.. I go thru a set of cats ever 1 YEAR. I have have receipts of all the times I've had to change my catalytic converters (dual cats) every single year. How can this be??

The can has been tuned via custom chip, engine tuned up and still runs lean. There HAS to be something wrong but even my engine builders can't find it? Obviously I can't be forking out $600 every year on catalytic converters!!

When I first start the car when the engine is cold (not started in say 8 hours), unless you wait like 4-5 mins or more, the engine is very chopping when they press the gas. The throttle response runs like there is too much gas and nearly stalls when you press the gas a couple times fast.. Once the car warms up 5 mins or so the car run perfectly. I'm being told the reason is because the engine is running too lean and the excess unburned fuel is killing the cats. If that is the case then WHY.

Thanks

 

Have you ever changed your fuel injectors? If some of them aren't flowing right, your car will NEVER burn the fuel properly no matter how much you try and tune it out.

Could try putting the stock chip back in. It's known for being a bit on the rich side. Most aftermarket chips will lean out the fuel.

Do you have BLM readings? What is your fuel pressure set at? O2 sensor is getting a signal?

I had the startup = choppy feeling. A set of those Innovative Wiring 1/0 battery cables solved that problem.

Exhaust leak would give you a lean reading.

Plugs and wires need to be good. If it's misfiring, it will overheat the catalytic converters, leading to an early demise. But my first thing to wonder about would be the fuel injectors. Our cars are getting to the age where they all seem to go through the original multecs. Especially now that ethanol is in all the gas we buy.

 

interesting.. What is the "Innovative Wiring 1/0 Battery cables"? I believe they are the original (leak I have not changed them since I had the car since 1998) injectors and highly doubt the first owner did.. So they would be the originals. How long do injectors last usually on our V8's and is there a way to test each to see if any are failing? I do know a couple are might some clicking noises by was told my engine builder this was normal.

 

https://www.thirdgen.org/forums/afte...ery-power.html

http://www.youtube.com/watch?v=Emnax2J4FX4

To test your injectors, go here: http://www.youtube.com/watch?v=_g8PdrT0MCU

I'd say you have the original injectors. And if you don't, they're still going to be the old design. Like most people on TGO, once my new injectors went in, the car idled and ran smoother than it did when the car was brand new. The old Multec injectors that GM put in our cars was never designed for ethanol. The new Bosch III design has no problems with ethanol. (I'm referring to the 10% content in gasoline, not E-85)

My injectors died about 2 years ago. Had about 40,000 miles on the car at that time. So it's getting to the point where age is the determining factor rather than high mileage.