Failed idle test

[Vanner1993]

I went to inspection and passed 2000 rpm test, but failed the idle test. It was way high like 1500 Hydrocarbons. The 2000 rpm test was more then good. What could cause this? I am gonna try to run codes today.

 

[jhammel85]

Damn NJ.

You are running cat's right? I take it that it's had a recent tune up? Is the idle at 750 rpm (manual trans)

 

[Vanner1993]

Yeah both cats are on, it idles average, but I have no tach. Yes a manual trans. Recent tuneup along with all top end gaskets etc. New valve stem seals, new plugs, etc. I ran codes today and I can not remember the #'s because I blew another dam brakeline. But the only engine related was poor circulation egr? My teacher for shop said it may be a bit clogged but would not cause unburned gas at idle.

 

[Psychopete]

I would run the tests again and see what you come up with, and resolve what you can. Poor fuel atomization is also seems to be a common cause (eg, injectors not working up to snuff or low fuel pressure - the fuel pressure is part of what atomizes the fuel). With all of that work done, be absolutely sure there are no vacuum leaks.

 

[Hahnsb2]

Pulling the SPOUT connector so it runs at base timing helps, but probably not with the HCs that damn high (limit here is 220 at idle).