what causes the engine to run rich
 

Hey I have a honda civic ex D16Y8 year 89
I have been trying to get my car to pass smog and i don't have the money to take it to a smog repair center and i just want to learn how to do it myself.

Right now the engine is running rich i know that means too much gasoline and not enough air.

What could be the causes of the engine running rich?

change air filter, gas cap and 02 sensor. those are the normal causes.


do you have a check engine light on?

there is no check engine light on

thanks for the clue i will look into it

The engine is designed to run rich until it warms up. If your engine doesn't warm up to normal temperature (wrong thermostat (should be 85C / 193 F), or thermostat stuck open), it will fail smog.

Also check the little vacuum line on the back of the fuel pressure regulator, I think on those it should go to a solenoid on the firewall. There should be a diagram on the hood.

How rich is it running? Clouds of visible black smoke-- or just failing on HC and CO? What were the smog check numbers (and limits) for all 3 pollutants? Is this a California car with the EGR system?

Yea I made sure it was at running temp before I took it to the smog test center. but i may need to get a new thermostate. when i had the car there im pretty sure the temperature was around 100 degrees F

as for the vaccum pressure regulator he checked it for me and showed me that it was at 20 instead of 18 and he played with it to show me that it was running rich and he made it run just under the limit for hc showing me how the computer compensates

it is not passing hc mostly, it is a california car
the limit for hc is 100 and it was running between 300 and 400 at idle

what does EGR stand for

for the O2 sensors he said they seem to be working fine but the only sure way to make sure they are working correctly is with a siliscope (im not sure how it is spelled) a test to make sure the voltage to the O2 sensor is reacting within a milisecond

Start by inspecting/replacing the plugs, wires, cap, and rotor and checking the ignition timing with a timing gun.

A 98 Civic EX (D16Y8) does not have an EGR system.

Operating temp for your engine is about 200F.

yea do a tune up and clean your iacv
http://www.team-integra.net/sections...ArticleID=1174

ok this is what i have done with the car since it first failed smog,
new cat
changed oil
checked plug wires, plugs and gap-good
distributor cap and rotor may need new but looked good
put valve clearance to stock intake .008 inch, exaust .010 inch
AICV is new
cylinder comp is at 150 i was told it is good
timing was checked with timing gun set at 12 dgrees btdc

i think that is it if i remember something else i will put it down
for my intake i have a cool air intake the aem v2 carb legal if that might help at all

have you tried to clean motor with seafoam?

i have put some feul injector cleaner. is seafoam different and how would i put it in the car