Failed Emission test

Im reaching out to you guys and gals hoping you might be able to steer me in the right direction, I went to take my smog test today and failed one portion Idle speed HC was high. Im not sure what that means or where to begin to work on the vehicle, it runs great, but there is a somewhat strong smell if its idling in my driveway, not enough to make you sick but it is noticeable, I should mention I have only one cat but its after the O2 sensor. The vehicle is a 1989 Bronco 5.0 302 XLT all stock with the exception of a flowmaster 40 series muffler.

I have done some research and should mention that since I purchased my Bronco, the temp gauge barely moves past the first line on the left, even while driving with the AC on and in traffic, Im thinking the thermostat is sticking open and not allowing the truck to get up to normal operating temperatures, just a thought, or a bad Cat, I have no CEL or anything of that sort, and it does have an unburned fuel smell, anything to help me pass emissions and save some fuel will make me happy happy happy haha

JLasvegas,

I am so glad I don't have to worry about emissions here. allows owners here to have all kinds of cool rides.

JLasvegas said:

I have done some research and should mention that since I purchased my Bronco, the temp gauge barely moves past the first line on the left,

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Mine doesn't go past the o in normal so I wouldn't worry about it.

JLasvegas said:

or a bad Cat,

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Could be. But I don't think that it other wise it would fail some of the other tests.

JLasvegas said:

and it does have an unburned fuel smell

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Spark plugs might be dirty. When was the last time all 8 were changed? and if your not a performance nut, replace them with the cheap ones. Just make sure you don't get the (junk) cheap ones.

Other things I can think of include (but not limited to)

air filter

injectors (mot likely not... 5% chance)

EVAP system malfunction

The air pump (might be pulling at straws their)

All I know, is because you can smell fuel its either going to waste (not getting used in the cylender) or leaking from some where. Best of Luck.

Thanks Skitter, I will look into those items. I purchased the Bronco from ebay and have only had it about a month, have not really done anything to it except install a new drivers side exhaust manifold that was leaking, In the state of Nevada, since I failed, I have to have a Official Smog station do the repairs and if it exceeds 450.00 then I can get a one year exemption, So Im thinking of changing the plugs, wires and change the oil myself before taking it in for them to look at. After I do pass, I can register it as a classic vehicle and never have to smog it again, you just cannot go past 5k miles a year which I never do

yo J,

As Skitter advised &;

Try a Self Test for Diagnostic Trouble Codes (DTC)s by my pal, BroncoJoe19

http://broncozone.com/topic/14269-code-reader/page__pid__74587__mode__threaded

Joes also shows a vacuum leak test; and, check vac w/vac gauge

The vacuum gauge should show around 18-22 in-Hg @ idle & maintain a steady needle. Rev it up to ~2500 rpm, hold it steady, and you should see the needle drop, then slowly increase to a level close to the idle reading (though slightly lower is normal).

Gas Saver Vacuum Gauge, PM1520, 2 inch http://www.autoparts2020.com/rsdev/part_detail.jsp?PART_HDR_ID=87069

Run vac hose through clutch blank and use a grommet or =; attach to vacuum tree on intake manifold; Vacuum Tree Location pic by Booba5185 @

http://i14.photobucket.com/albums/a304/booba5/overhead-2.jpg

and; The air handling system is designed to provide defrost when no vacuum is applied to any of the three air door vacuum motors. This is done to prevent a situation where defrost cannot be obtained due to a system vacuum leak. Instead, a leak in the vacuum control circuit will send all airflow to the defroster outlets. This condition may occur during acceleration (slow leak), may exist at all times (large leak) and may happen only when certain specific functions are selected, indicating a leak in that portion of the circuit.

The engine temperature must be greater than 50° F for the Key On Engine Off (KOEO) Self-Test and greater than 180° F for the Key On Engine Running (KOER) Self-Test.

Run it around to heat the engine up and shift thru all gears incl Reverse. Then turn off all accessories/lights, etc. Use heater temp (feels hot) to help determine if it is warmed up enuf for self test KOER

Engine Coolant Temperature & Sender Testing; "...If you take that single wire that Seabronc is talking about and ground it to the block the guage will imediately go to HOT that will tell you if its the guage or the sender . There is another mounted back farther in the intake and that is for the EEC to determine timing curves and injector pulse time..."

Source: by BLADE262US & Seabronc (Rosie, Fred W) at Ford Bronco Zone Forums

Testing; "...Pull the R/Wh wire straight off the sender & ground it to the block, intake, or head. Then turn the key to RUN. If the needle pegs, replace the sender. If not, diagnose the circuit

Sender Location Diagram Source: by Gacknar (The Mall-Crawler, Jeremy, "Big grey megga beast") http://www.supermotors.net/getfile/265237/original/GT-40%20lower%20intake.JPG

Make sure A/C is off and transmission is in Park (automatic) or in Neutral for a Manual & release clutch.

Do Key On Engine Off (KOEO) portion first.

And Post em here according to:

KOEO

&

KOER

=============

Smog Diagnostic Chart; see http://www.recarbco.com/technical/smog/smoginfo.html

altho most apply to carb engines, a lot applies to EFI

&

by Recarbco Fuel Systems recarbco.com:

PCV valve; Is it sticking open or sticking closed? Are the passages clogged or is the hose itself collapsing? A defective PCV can cause high CO or HC readings. A high CO reading will result if the crankcase oil is contaminated with fuel. A high HC reading will result if the PCV valve does not meter the airflow properly, if the incorrect valve is installed of if the vacuum side of the system is leaking air (such as through a cracked or broken hose, loose fitting, etc).

Another condition to be corrected or eliminated is catalytic converter failure or a blocked exhaust system. To check for proper operation, first block the wheels, put the vehicle in Neutral or Park, disconnect the air injection system and check that all fluid levels are satisfactory for safe operation. A) Disconnect the evaporative canister purge line.

B) Measure the HC, CO, CO2, and O2 tailpipe readings with the engine at idle and at normal operating temperature.

C) If CO and HC are above specs but CO2 is low and O2 is between 1% and 2%, the problem could be either temporary saturation of the catalytic converter or a defective cat.

D) To check for temporary saturation of the cat, run the engine at 2500 rpm for three minutes and observe the HC, CO, and CO2 readings. If the cat is functioning properly, CO and HC readings should decrease and CO2 should increase. If CO and HC do not decrease but CO2 does, repeat the procedure. If CO and HC still do not decrease, go to step 6 above.

E) Check the O2 level. If it is below 1%, the engine may be running too rich. Investigate and repair. If the O2 rises above 3 or 4%, the engine may go into a lean misfire, causing HC to rise. Again, investigate and repair. Note: the use of oxygenated fuels may push the O2 up to 3 or 4% even though nothing is wrong.

Update, performed an oil and filter change, a full tune up including the following, plugs, plug wires, cap, rotor, airfilter, and pcv valve and she passed emissions easily. Good to know that it was something so simple and nothing major. I want to thank you guys for all the help and info.