gross polluter zr1

[Harold Broerman]

just bought a 90 zr1 with 10 k miles. took it to get smogged, and it failed as a gross polluter .scan tool showed no problems and no codes. car seems to run great,but the mechanic said it was dumping fuel,and running super rich.anyone have any thoughts on this?id really appreaciate any feedback,as id really like to drive this car . thanks, Harold avbattery@aol.com

[1990 quasar blue]

The first thing I would do is post this in Zr1 Tech. I think it will get more traffic there. Also, my first thought would be injectors failing/sticking open. I would also think that the drivability would be poor as well so I may be wrong.

If it's dumping fuel and running super rich, the question should be why is the 02 sensor not picking this up?

Best start is to pull the plugs check the condition. That will at least give you a starting point with out having a data scanner of some sort.

What you may find is that you will have some stuck injectors and lazy O2's. Might as well do a general tune, plugs wires, oil, coolant and trans fluid.

[Z Factor]

Hello Harold and welcome to the forum.

My suspicion would be a faulty injector/s.
I agree with Jeff that you should inspect your plugs first and go from there.
Feel free to ask other questions you might have as we would all like to help get your KOTH running right.

[rkreigh]

if it's been babied alot there is likely carbon build up which can cause the car to fail. get it good and hot. a leaky injector which the 90s are a bit famous for can do it too. a good once over with someone willing to test the car.

change oil, plugs, get it good and hot (drive it HARD) and retest.

my 90 failed the first time but passed with flying colors with just this "fix"

the lt5 is a carbon machine, and many don't drive them hard enough to clear the throat. the car revs safely to 7k, don't be afraid to hit it.

[flyin ryan]

Originally Posted by rkreigh

if it's been babied alot there is likely carbon build up which can cause the car to fail. get it good and hot. a leaky injector which the 90s are a bit famous for can do it too. a good once over with someone willing to test the car.

change oil, plugs, get it good and hot (drive it HARD) and retest.

my 90 failed the first time but passed with flying colors with just this "fix"

the lt5 is a carbon machine, and many don't drive them hard enough to clear the throat. the car revs safely to 7k, don't be afraid to hit it.

i agree, best place to start anyway's. keep us informed.

[GrayZ]

either way...drive it like you stole it...

[Harold Broerman]

I want to thank all you folks out there for your tips, but id like to tell you what we found. in the quest for more performance, the previous owner gutted the cats.got new ones on the way. thanks again, Harold.

[cuisinartvette]

Biog difference, eh? Bring it down to some of the functions we have in the Valley if you have the time. Some real cool cruise-ins and GTGs....Like to see more Zs out and about.
I know they are out here, ya just never see them.

[tccrab]

Originally Posted by Harold Broerman

I want to thank all you folks out there for your tips, but id like to tell you what we found. in the quest for more performance, the previous owner gutted the cats.got new ones on the way. thanks again, Harold.

New cats?

From where?

As far as I know, there are *NO NEW* cats for a 1990 ZR1 *ANYWHERE*.

It's against Calif. state law to buy a used catalytic converter from a business of any kind. You can buy them from a private party, but you get what you pay for.

If you don't already know, the catalytic conveters are integral to the exhaust manifold. GM hasn't had stock of them for years and years, and nobody has ever had any made in the aftermarket.

This is the perfect time to order up a set of headers from Marc Haibec and aftermarket bullet cats. Then take it to the smog nazi's and tell them that you can't buy new catalytic converters, you will get an OK on the headers even though they are not CARB approved (nobody makes CARB approved headers for a ZR1).
This is your One and ONLY chance to get one on the smog nazi's here in Calif.


Good luck!