S10 having trouble passing Smog

I took in my 84' 2.8L S10 in to get smogged, but it did alright with the load test and FAILED HORRIBLY at idle. :screwy:

Anyone an expert on smog that could help me out?

Here are some numbers:

RPM: 911
HC: 2000 PPM (His sensor wouldn't go any further.)
NO: 19 PPM
CO: 0.12%
CO2: 7.7%
O2: 9.4%

RPM: 2489
HC: 192 PPM
NO: 227 PPM
CO: 0.04%
CO2: 13.8%
O2: 1.5%

The truck runs like a champ, never missfires, what could be wrong? I know HC stands for unburnt fuel, but was the sensor SOAKING in gas for gods sake?

Back when I had to run my cars through tests I used to do a complete tune up, and then add about 4 bottles of gas line antifreeze (methol hydrate, which is straight clean burning alchol designed for running in cars, plus it's used in cooking fondoo's)
I passed with flying colors every time, even though my car was tricked out where I shouldn't have.

Sounds like timing.

Also, ever done a tuneup?

you truck is 20 yrs old?? maybe you can register it as a "collectible"? no smog test required ever again

collectable.. :lol2: I wish I was so lucky.

I did some more searching and I came across this:
http://www.recarbco.com/technical/smog/smoginfo.html

It's a smog diagnostic.

Judging by the chart, I might have a cracked vacuum hose, so yesterday I looked under the hood and, look at that... its cracked reeeally bad!

So I go by the auto parts store and buy some little hoses for $1.

It would be unbelievable if this was the problem.

I'm also leaning towards a few other things.

ha ha ha blazerLT and his "tune-up", but how true that is... basic maintinance is the key.

ha ha ha blazerLT and his "tune-up", but how true that is... basic maintinance is the key.

Got a problem with my advice?

96Civ, I hope that the hoses were all your problem, do let us know if it passes

if you miss your 68 so much I know where there's a sweet 69

no dude, i just think how funny it is that most people don't ever do basic work on their cars until something big happens to it.

no dude, i just think how funny it is that most people don't ever do basic work on their cars until something big happens to it.

Ah, that is true, that is why I like to see if they have done it yet.

like me friend Todd, didn't care about leaking oil until "the danger light" came on... what a tard... he's put on 40,000 miles in a few months (drives everywhere... and is unemployed)

As an emission tester in PA the number 1 cause for high HC is worn or dirty spark plugs for fuel injected engines , for the old school carb engines most times it the mixture set screws need a little adjustment and new plugs

Do you know where the idle mixture screw is? I'm not mechanicly inclined, but it looks as though the mixture is set by the computer, in which case I can't do anything about it...

they are at the base of the carb, if they have never been used then they are still covered with a metal cap that has to be punched out , most time you must remove the carb and turn it over and drill and then punch out the mixture screw cover caps

i used a bottle of 104 emissions something or another in my old 87 cutlass (350, cams, roller rockers, hydraulic lifters,) and it passed like a champ. of course i ran it up and down the hwy in 2nd gear getting it good and hot, (not to mention killing every mosquito in a 10 mile radius) before i brought it in.

I work at a State Vehicle Inspeciton station in Texas. I recently bought an '87 S10 Blazer 2.8 V6 2dr 2wd auto and I did did a sample state inspection on it to see how it was running. Everything was perfect because the previous owner tuned it up recently and replaced the EGR system. Therefore, the HC, CO, and NOx readings are lower than most vehicles I inspect.

As you stated, your HC reading is basically an indicator of how much unburned fuel you are simply blowing right out of your tailpipe as a result of incomplete combustion. For example, I am willing to wager that your gas mileage on your S10 sucks bigtime.

Simple fix: do a complete tune-up (this is what we tell all people who fail specifically on high HC and CO readings). It will obviously make your engine run better and cause your emissions readings to go way down, but it should also give you at least a little boost in fuel economy since you'll be wasting a lot less fuel than you previously were.
Get a new air filter, new spark plug wires, spark plugs, distributor cap, and distributor rotor.

(Timing could also be a problem if the above recommendations are not enough...although I would definitely get the complete tune-up done first and foremost.)

Big vote for retarded timing.

Hey just move to kansas. They just make sure you have an engine under the hood. They dont check anything. sorry i cant help, anyways good luck dude.

Actually the car gets excellent gas mileage. I spend about $100 a month on gas, and that is about a 30 mile commute every day.

Updates: I took the car to a smog diagnostic and they basicly said my carb is most likely the problem AS WELL AS the EGR (It was full of gas) I ordered a carb rebuilding kit and I am working on fixing the EGR and PCV.

not sure what state that is for, but i am an inspector in texas, in an emissions county. That is the highest HC count i have EVER seen(and i've seen some pretty high ones)....definately running rich at idle. If your EGR is full of gas, then u definately have something leaking more gas into the engine than required at idle, hence the carb needing attention(rebuild or whatever is needed)


@borninski: ESP machines SUCK!


"EDIT" Ya know, someday when i get more time i might read the whole thread all the way through....until then please bear with me guys...lol