Hi everyone-
I just got the engine rebuilt in my 1983 Civic, and I am needing it to pass smog. It failed right after because the hydrocarbons at idle were too high, so I talked to my mechanic and they told me it needed to be driven to seat the pistons and burn off any excess build up from the rebuild. So we drove it a couple hundred miles and brought it back for testing, but the hydrocarbons were still too high. When I got it back again they told me they had leaned it out so that the engine would have to work harder, and that I needed to drive in more, at least 500 miles. I've driven it about another couple hundred miles but I'm starting to worry that the lean condition might actually cause damage. It does stall right after warming and start up, and every once in a while at a stop light, but that is to be expected from the lean condition. Any input or advice? I really need to get it to pass smog so I can finally register it, and I am of course extremely concerned about any potential damage this could cause. Thanks all!

(sorry for the repost if you saw this in the Engine Management forum, just trying to figure things out asap!)

 

First, what state are you trying to get this car registered in? As for your smog problem, are you using a brand new catalytic converter? Are you using a newer carb like a Weber 32/36?

 

So I am in CA, I talked to my mechanic after the weekend and asked about how much they had leaned it out ect. and going from the behavior of the vehicle and from their response, I'm going to assume it won't cause any damage... but as far as smogging goes, we will see. The catalytic is the original, and I've had multiple opinions that it's probably not what is causing the fail at the moment, but again- I'll find out in the future. The carb is also original. Continuing to drive it- I've noticed the intermittent white smoke from the exhaust has stopped, so I'm going to hope that is a good sign that any initial blow by issues from the rebuild might be subsiding? I'm really new at automotive education, but I'm learning. Still much, much more to learn of course.

 

High hydrocarbons is usually a sign of a bad catalytic converter ($300 to $400 for a new cat). Let's not forget install fees/welding ($100 or so)

First, I'm going to assume you are using new sparkplugs (gapped correctly) and new wires, and your ignition is system is working perfectly since is very important in this aspect. Also, prior to taking it to the smog testing center, did you at least drive it for 30 minutes or more? I'm also going to assume you changed your oil prior to taking it to smog shop for the test? Lastly, prior to changing your cat for a new one, have you tried using some Seafoam and driving around to burn it all off before buying a new catalytic converter and installing it? Also, fill your tank with 91 and add some of the "snake oil" Guaranteed to Pass emissions additives to your gas tank before you take it in for testing.

Or just do it the easy way and find a sleazy smog shop, pay the asking price to "pass" smog.

 

What are the other numbers for smog test? this is a dynamic test and all these values give you a picture of your real emission O2, CO2, HC, CO and NOX in that order for the 15 and 25mph test

here is a good explanation for those numbers

https://www.916smog.com/smog-fail-categories

and here a lambda calculator

http://smogstats.com/Lambda_CAT.aspx

Best

 

I'm quite a bit late in this discussion but...

https://www.ebay.com/itm/1980-1983-H....c100752.m1982

...may be a good bet plus it's an easy direct fit DIYS install!