Emissions and Bushings

[Weber3211]

I have this horribly loud creaking noise coming from my front suspension. It only happens on my way to work in the morning when it's cool out, so i'm assuming it's my bushings up front. Is this right or could it be something else? If needed I can take a sound clip.

And secondly, I failed my emissions test due to excess hydrocarbons, which means I have too much unburnt fuel. Could this be from spark plugs? I don't have cats so that could be it too, but my hydrocarbons were more than twice the legal limit which is what makes me think it's the plugs.

Thanks guys!

[PAintballa45]

its because of the cats, or lack there of. Run self diagnostic for codes, specifically the 02 sensors. Why did they run emissions on a 91 anyways?

[Weber3211]

we started doing emissions on all vehicles here in CO which is ridiculous because we have some of the cleanest air in the country. i should have figured the cats would be the problem but my emissions levels were so high that i thought it might be something else as well.

[robomatic12]

You should do a general tune-up before you go hunting for other things, like suggested check the 02 sensors with the ecu diagnostic mode. Air-filter, fuel-filter, plugs, oil change can make a difference, pcv valves, blocked cat converters. Make sure the Z is running in top shape.

[Z31toZ32]

i there is a hose on the top of the plenum that you can unplug that magically fixes emissions problems. some guy made a website on it and it was recently discussed on here.. search on google.

[NissanFairladyZ32]

Its because you are not running cats, replacing 02 sensors could help.

[robomatic12]

LOL good catch fairlady, I didn't see that. Of course you need cat converters to pass a smog test!! Throw them on and pass the test, then you can put your test-pipes back in.

As for the creaking, check the sway bar end links for excess slop or seized joints. Shake/rock the suspension checking for tie rod play, ball joint play, wheel bearing play. Look over all rubber parts for cracks or wear and tear.

[es.biggs]

yep cats eliminate (or try to eliminate) unburnt fuel before it goes out the tailpipe.