Hey guys need help, I have taken this car to multiple techs and no one seems to want to work on it and they want to charge me 200 just to inspect it last time they did the inspection they told me I needed a new carb, got a new carb then they said need to rebuild heads did that, now still won’t pass and they want 200 more to tell me why is not passing, any help will be appreciated, I have uploaded the inspection report

 

Get a new fuel cap that will fix failed cap.
Is your check engine light on or not working at all? That will cause the obd failure.
How old is your cat? Are all your service items done... Cap rotor plugs pcv valve? High Nox at
The 15mph test is either timing off, egr not functioning or the cat. Check them all. Make sure your getting vacuum at the egr make sure the egr is working and the egr passages are clean. Check timing and set it to stock. Check the cat if its original or very old. Replace it

 

It was just the bulb for the check engine now that’s fixed, the egr valve was replaced recently, not sure when the converter was replaced previous owner said he replaced cat and exhaust system in 2006, one tech said it was the converter is there a way to check for the converter, car had been sitting for about 8 years it runs really good but the smog check has been a hassle

 

Check your timing. It could be too advanced. It could also be too lean at idle. Check for vacuum leaks as well.
And just because a carburetor is "new" doesn't mean it's properly adjusted for your application. If it's a Q-jet, they were made for hundreds of applications, and need to be properly tuned for your engine.

 

Your definitely lean at idle. When the carb was put on was it adjusted?( Air/fuel mixture) Double check your timing juat a few degrees off will cause your problem. Make sure the car is driven a while defore the test to make sure the cat is good and hot. No real way to test the cat but if everything else is withing spec and working properly then the cat would be your only next option.

 

Thanks for all the advice will try that is there instructions anywhere I can fallow to adjust carburetor

 

Read through the carb section here, there are several posts on how to adjust the Qjet. There is also a facebook group dedicated to Quadrajets. Finally, call Cliff Ruffles at Cliffs High Performance is a great resource. He loves to talk and has written a couple of books on them.

 

With the vehicle on a lift and running, on infrared thermometer is used to measure the temperature of the exhaust pipe going in to and out of the cat. If the temp is the same, or very close, the cat is dead. Exactly how much deviation is acceptable, I do not know.

 

Update:

I've made the car run even leaner. Used the #68 jets and the 50V metering rods. With help of the AEM folks, I finally got a working Wideband gauge on the third try, and unless I goose the throttle, it'll run at 15.3:1 AFR consistently, which is a little lean.

Failed again, this time even worse than the last two times. Still high HC and CO, still negligible NOx, all of which indicates a rich condition. There is something wrong if the car runs leaner than it did the first time, and it is failing the test with a progressively worse "rich" running condition.

There are still a few things I can adjust. I need to check the APT settings, and I can make the pump on the carb shoot less fuel. I can also increase the size of the idle tubes to allow more air during idle (the cam likes a rich mixture at idle, though).

Going to try again. Wish me luck.