failed emmisions due to hi idle hc

my 93 ranger 2.3 5 speed failed the hc part of emissions this morning.allowed is 220..mine read 230...new plugs, wires,timing belt,water pump, cat is recent, truck runs fine..driven 250-300 miles per day getting 25-28 mpg at 70 plus mph..recent oil change..no mechanical problems i can detect at all..i can not see or hear any vacum leaks....it might be possibly throwing a cel...but the bulb is burned out so i can't say for sure on that..what will reduce the hc level to pass ?? thanks...pj

Ford added the dual spark plugs because of emissions requirements, so both coil packs need to be working.
The exhaust side coil is used for starting, intake side coil isn't used until engine is running.
So you can often test coils by swapping them, if you get a no start then that coil is bad.
Or if you have an old timing light test if intake side coil is sparking while engine is running.

There are no noticeable effects of a failing intake side coil, other engines run just fine with one coil or coil pack, lol, and so does 2.3l, but it can effect emissions and tach, low RPM reading and will often set a code and turn on CEL.

All fuel injected engines are run richer at idle this prevents overheating of combustion chambers, this also raises HC, but it should stay below requirement for that model year.

1993 should run the AWSF-32PP spark plugs, speced gap is .044, I would increase that to .048, that will give you a more complete burn at idle.
And just a heads up, any time you are using a Ford coil pack system it will be a Waste spark setup, so either run regular copper spark plugs or Double platinum, single platinum is a waste of money on this type of setup and will wear out same as regular copper.

Rule of thumb is larger gap gives better low RPM performance, smaller gap better high RPM performance, the spec of .044 is the middle.

Also what is the idle RPM?
2.3l usually has a higher idle, manual trans 700-750, auto 800
When you get down below 700 the HC will go up.

Dirty injector tips can drip fuel at idle vs spraying it, this will cause higher HC readings as fuel and air are not mixed completely at idle.
Run a can of Seafoam or similar treatment in the fuel tank, this can help clean injector tips.

In my area they fail you if Check engine light(CEL) doesn't come on when it should, so burned out bulb is a no pass, they won't even test vehicle.

Also run a higher ethanol content fuel for the test, E10 is 10% ethanol/90% gasoline, this lowers HC.
HEET is sold in auto parts stores it is an alcohol based product used to remove water from gasoline but also will lower HC.

Just FYI, Gasoline and water don't mix, and water is heavier than gasoline, "bad gas" is often when water in the storage tank(gas station, or last delivery truck) gets pumped up and into your gas tank.
It will settle to the bottom and get sucked up by fuel pump causing rough running, not high HC though.
Ethanol/alcohol does mix with water(H2O), and will still "burn", so running E5 or E10 helps keep gas tank fuel free of water and acts as an anti-freeze during winter months because unmixed water freezes at 32degF, mixed with ethanol it won't freeze until -100degF or more
HEET is sold for this purpose as well.

Thanks..running e10 as far as i know..fill up every morning at the same place and the pump states it has a 10% mix of ethanol..don't recall the exact plug it is motorcraft as i work for a major parts dist that houses motorcraft, ac'delco..etc..i do remember the plug said fine wire electrode...all systems as far as idle, running, acceleration are fine..no stumbling or hesitation..my son is a certified tech..talked to him..as he does all the maitinance..said he thought might be the O2 sensor since that hasn't been changed since i've had the truck for 2 years..i know my '96 ranger 2.5 had two O2 sensors...how many does the '93 have ?? been trying to google..but an't find out..looks like maybe one from trying to look at fuzzy pics...thanks again..pj

Two thoughts. The older pre-OBDII systems did not check the catalytic converter efficiciency. The second O2 after the converer looks for a stable output w/o any excess O2s floating by, more or less. It is just a monitor. You would be able to see it in the pipe immediately after the converter.
I would look down the intake, past the throttle plate, and inspect for a 'coated' intake manifold. The PCV feeds its stuff right into the intake, and can end up coating the intake with condensed oil vapors, it seems. Well, mine does, I think.
I would get some converter safe Carb or Intake cleaner and squirt the beans out of the intake. I would actually remove the throttle plate so I could see the intake and use the spray to clean off the inside walls. My truck would not pass its emissions test when it had ~5k miles on it, and there was no 'fix' except to raise the idle speed to ~900rpm.
It finally passed using that 'get around', but was not a good option in my opinion.
I found that douching the intake, and letting the spray cleaner sit on the inside of all the closed intake valves for a while after doing the spray, led to an engine that liked to idle run and start better. And it passed the test every time since using the cleaners now and again. You will get a cloud of smoke on the next startup, so be prepared, but don't worry.
tom

Pre-1995 2.3l engine will have 1 O2 sensor.

Could be O2 sensor but I would think that would skew HC at all RPMs not just idle, and computer software often ignores O2 data at idle, same as it does when engine is cold, because idle needs to be a richer mix.
And your MPG would go down as well if O2 was showing false Lean, making computer add more fuel than was needed.
But if O2 sensor has close to, or more than, 100k miles it is due for replacement in any case.

Could try cleaning MAF(Mass Air Flow) sensor, MAF sensor data is what computer bases 14:1 air:fuel mix on.
Ford uses a "heated wire" MAF sensor, these tend to fail Lean not Rich, i.e. coating(dirt) on "heated wire" makes MAF data report less air than is actually flowing in so computer adds less fuel and you get Lean condition, less HC, O2 sensor corrects this Lean condition but you can get Lean codes because of it.

The PCV Valve check is a good idea, PCV Valve should be closed at idle, highest vacuum in intake, so no oil vapors should be coming in from valve train crankcase, if it is not closing all the way that could skew the HC at idle.

Two other things to consider: Thermostat and Coolant Temp Sensor. Either one could cause the HC to be higher than expected to a degree. If the coolant didn't get quite as hot as specified, or the sensor didn't detect the coolant temperature, the computer might be adjusting a bit rich.
There is a table of resistance values for the CTS at specific coolant temperatures. You can use a non-contact thermometer to measure the coolant temp in the upper radiator hose, stat outlet. I would expect it to measure a bit under the stat temperature, but sor of close.
Have you checked the fuel pressure regulator to see that it is close to spec? A failed regulator will/can cause mileage to be close to 1/2 normal, though you don't report any mpg concerns. High 20's on the highway if you keep it under 70, in the mid 60's, should be reasonably expected. IMO.
If the heater will not drive you out of the cab, then I'd take a closer look at the thermostat.
tom

Thanks for all the input..cleaned the throttle body throughly before the test..temp guage runs about 1/3 on the dial regardless of speed...always constant once warmed up..plenty of heat as we replaced the core, water pump, timing belt and tensioner last month...this truck sat for about seven years prior to me buying it..the plugs, wires, and timing belt were the original from Ford...all that has been replaced prior to the test..truck has 259K on it..today just to see if I could get it through...I put a bottle of Royal Purple Max fuel additive to a full tank of REAL gas...no ethanol...drove 250 miles on my route..and ran it through the test again..the HC read HIGHER than it did on the previous test..I'm guessing the O2 sensor is the original from Ford as everything else was...before I replaced those items mentioned above..BTW this model only has one O2 sensor..before the cat..oh...the cat is less than a year old as well..thanks for the help...pj

Pat

All really good info as always. I was going to suggest to you to get the cat really hot before you test but it looks like you already did that. Read this thread as the OP had the wrong cat put on his truck and that is the reason why he failed his test. So if you have not tested since the new cat was put on I would look at that also.

http://www.therangerstation.com/forums/showthread.php?t=164149

Bryan

thanks...passed he test last year with the new cat..where is the pcv valve locate ?? i'll get a new O2 sensor today...

PCV is 'in-line' behind the alternator or PS pump depending on model. There's a canister on the side of the block under the intake. The canister has an oil separator to grab liquid oil and route it back to the crankcase, letting vapors continue out through the hose.. The PCV valve is jammed into the end of the hose leading from the canister. The continuation of the hose goes on to the intake manifold.
Does your fuel system hold pressure after shutdown? You might have a leaky injector.

Have you pulled any stored EEC-IV codes? You can use an analog VOM or a dedicated connector to read the codes. You could have a problem with the evaporative system that is making it read too much HC. You could have a break in the ribbed tube feeding air to the engine. They can crack and allow un-metered air as the engine moves under load and opens / closes the aperture.

Got the truck through emissions by simply testing at a different location...took it to a test station I pass every day on my route in a town about 20 miles down the road...two previous tests had HC readings of 230 and 256 ...reading today was 133 on the HC..what did I do to make it pass ?????????? not one damn thing...just a different location..exact same test procedure...guess all locations are not calibrated the same...regardless of what one of their "techs" told me...haha..Thanks again to all who offered advice..I will change the pcv since I feel the one in it is most likely the one that Ford installed in '93..

I think they are calibrated.

I would suspect your vehicle before the test equipment, could just be computer is getting old and electronic voltage is varing and failing to lean mix enough at certain RPMs now and then, or mix is being bias by a failing sensor.
One day it is good next day bad.

You might have found the 'sweet spot' in engine/oil/coolant temperature that allowed it all to come together and meet the spec. Sometimes it seems like there is a magic incantation that needs to be said, but there isn't. In some areas of the world, the engine actually produces exhaust that is cleaner than the surrounding atmosphere.
tom

I agree it could be as simple as the engine was the proper temp at the time of the test. For the first two tests did you run the engine at least 1/2 hour at highway speeds? Possible engine coolant temp senser out of spec?