12-12-2018, 11:02 PM
Join Date: Nov 2016
Problems passing smog...due to rough idle
I've been trying to get my beloved 88.5 Sammy smogged in CA, and I'm hitting some trouble. The tech did a sniff test and said it was clean as a whistle (as it should...just installed a new cat!) However, he said he couldn't do the test due to rough idle.
I checked and the Sammy idles around 800, dips slightly, then races to about 830...then slowly drops down to 800. Rinse and repeat. What could be wrong? Should I try another smog location?
Things of note:
- Had the carb rebuilt and calibrated by GuaranteedCarburetors about half a year ago.
- Replaced spark plugs, leads, distributor cap&rotor,ignition coil (my aftermarket tachometer works now instead of just spazzing out uncontrollably!)
- Replaced fuel filter
- Found clogged MCV jet, replaced that
- It used to die at low idle, until I enriched the fuel/air mixture (bonus: can now hit [email protected] RPM now!)
- Disconnected idle-up circuit
- Disconnected EGR (plugged the hose from charcoal canister to carb)- made it run smoother
- Adjusted timing to 10°
- Attached a vacuum gauge to manifold. Vacuum's at 21 at idle, but flutters by 3-4mm? If I rev up, the needle steadies. It fluttered much worse when I had the charcoal canister connected. When it automatically revs up, the flutter lessens.
What should be my next plan of attack? Someone suggested the distributor springs? Looking online about the vacuum readings point to worn valve guides? Even if it's worn valve guides, would it cause that revving pattern I described above?
Thanks for any insights in advance!
Last edited by Norad2000x; 12-12-2018 at 11:04 PM.