1991 ZR1 Failed Emissions

[Jason 91]

Gbrtng:

The degradation is the main reason I initially thought it was the OE injectors failing.

The gasoline was fresh. Before I took it in for the test, I drained the tank by driving it back and forth between Denver and my CO Springs office which is about 55 miles each way. I refilled it shortly before going to take the test. Also, the car was up to normal operating temperature. The frustrating thing, and I’m not sure if this made a difference, was having to idle for about 45 minutes while waiting in line. This caused the fans to come on a couple of times.

Goldcylon:

Where did you get the 1991 exhaust manifold/catalytic converter from? Did you get it from another member? I just had a member reach out to me. Thanks Greg!

Tomtom72:

The injectors are OE and with the ethanol here, I expect to be replacing them soon either way. Is there specific scan data we should look at that demonstrates the injectors are going bad or is it you need to see a continuing rise/decline in specific results?

I’m not going to let them fail me again for the air injection system after I’ve confirmed that all original equipment is in good working order.

Thanks for the link. I’m still learning (you seem like more of a mechanic than me ) and information is always helpful.

All:

Feel free to comment on any of these above responses. I’m trying to make sure that I respond to all questions asked because I really appreciate you guys taking the time to help me.

I will verify that it is in fact the cat that is bad before anything gets cut, but I have a couple of questions assuming that it is.

Assuming the exhaust manifold/catalytic converter needs to be replaced, how much R & R labor hours am I looking at for each? I’ve read the FSM (and Chilton’s for what it’s worth), but I have little practical experience so I’m having trouble figuring it out and am probably oversimplifying it.

Is a universal cat even an option as a last resort (I see some for sale)?

Are there any header options that I could still pass emissions with assuming everything else is in good working order?

Again, I appreciate all of the help you guys are giving me.

Thanks,

Jason