Running rich - failed emissions

1987 camaro z28 failed emissions - running rich - what should I be aware of - any easy solutions i can try before taking it to mechanic?

Has this car been modified in any way? Does it have fuel injection or a carburetor?

I thought you were going to take it to a mechanic? If you did, take it BACK there, he’s not finished!

Hi Mustangman - carburetor. Not been to mechanic yet. Thinking fuel additives. and any other suggestions. I read somewhere that a new battery might contribute and low tire pressure. Any thoughts? I had both of those btw. it’s a 350 with 100,000 miles.

Low tire pressure making a vehicle run rich , Nope - battery also Nope.
Where does this stuff come from ?


Just curious, is this the original engine? I believe the 350 was Tuned Port Injection (TPI). I had an 86 Camaro (IROC) with a 305 TPI.

yes it is all original even the upholstery. In good condition - runs great - made in Canada. I imported it - bought it from my friend who’d kept it in his garage for 15 years.

If this is all original and a 350, it has fuel injection. If someone has changed that, all bets are off.

1 Like

Many people find techron etc. and a long drive on the highway can help them pass. No check engine lights etc?

no ck engine light

will try fuel additive

seafoam? STP? both?

Techron and seafome seem to be the most popular, 1 is enough.

I had this problem with my carbureted '87 Toyota pickup. It turned out that the choke had stopped working, the lever had popped out of the coil, probably on that -17° morning. I had to drill out the rivets that held the cover on the choke, then put the lever back in the coil’s hook, no new parts. It’s an unlikely cause. Do you backfire?

Here’s the thing. No one could really offer any solid advice with that minuscule amount of information. For example, when you fail emissions testing, you fail a specific test- “not running rich”. It matters in the diagnosis if it was a dyno test and what section of the test failed. Or if it was some other type of test. The inspection report will list the specific test criteria it failed. For IM testing, they will also provide the other measurements being taken and those can also help diagnosis. High HC while idling or at some point in the drive test for example. Also, conditions leading up to the failure. I’ve had this car for 10 years never failed versus I just bought this off a guy that had it in a barn for 10 years makes a big difference. If you have that info, post it. You’ll get better advice on next steps. You reap what you sow :wink:


The vehicle should fail the emission test because someone installed a carburetor. As mentioned, this vehicle is fuel injected.

I wonder if it even has the catalytic converter installed?


1 Like

no backfire

Mary… does this car have a carburetor?? If it does, it is not a factory carburetor as no 350’s came with one.

1 Like

Or, high HC/CO2.


It has a carburetor - factory - made all in Canada. I know it’s weird, but there it is. It’s also an automatic which is even weirder eh?

nope carburetor is factory. just weird - made in canada. eh?

Look at the VIN. Is the 11th digit an L or N? If neither, what is it? This is the last letter before the numbers at the end of the VIN.

It never came with a carburetor.


1 Like