High CO Emissions (1 Viewer)

[IoN6]

Just tried to get Lucy SMOG'd and she failed... More than double on CO. I just purchased her back in December down in Texas. Drive home was uneventful, etc.

I do not know much about her, other than she is a 1993 with 174k on the clock. Exhaust appears to be original, assuming the cats are too. I did have some Lucas injector cleaner still in the tank (bone head on my part). Without pulling out the shotgun to start replacing parts is there anything you guys would recommend to try?

HC = 2.2543 (2.5 max)
CO = 51.8463 (25 max)
CO2 = 682.4043
NOx = 1.9088 (4.5 max)

Attached is the graph from the test (saw someone ask for this in another thread).

Any help is much appreciated!

 

[IoN6]

I swear there was an edit button before, but damn if I can find it...

One thing (probably major thing) I forgot to mention earlier was that I hosed off the engine compartment and it ended up missing pretty mad until I got it home and checked the distributor. Rotten eggs to the max. I drove it a little once it cleared up, but no WOT for 100 miles or anything crazy.

 

[landtoy80]

Put new cap and rotor and plugs.
Change oil. Drive about an hour before testing at hwy speed. Burn off all the gas.
Go up to Brighton (I assume you are in Denver) and gas up with 100% pure gasoline) Do a search on ethanol free station you will find the station. If you have time run Two takes of 100% pure gasoline.

Set timing to factory setting 3 dog if I remember correctly.

High co could be from additive or carbon fouled dist cap.

I was going to try the 100% gas for my next test but now going to register in AK.

 

[gsi18867]

Looks like a misfire in at least one piston as the tester is letting off the throttle(maybe timing, maybe plugs). I'd get that exhaust as hot as possible before bringing it in. Do you have the newer ( blue top) EGR regulator(prolly wrong name). My old green top opened the EGR too slow. The blue top opens too fast/early. It might help route those unburnt fumes back around for another try sooner. JMO

 

[landtoy80]

His egr must be working as his NOx is real low. As is the cats.

I know that every time I tried adding stuff to get it to pass the CO goes up.

 

[IoN6]

Put new cap and rotor and plugs.
Change oil. Drive about an hour before testing at hwy speed. Burn off all the gas.
Go up to Brighton (I assume you are in Denver) and gas up with 100% pure gasoline) Do a search on ethanol free station you will find the station. If you have time run Two takes of 100% pure gasoline.

Set timing to factory setting 3 dog if I remember correctly.

High co could be from additive or carbon fouled dist cap.

I was going to try the 100% gas for my next test but now going to register in AK.

Yeah, it was your thread that I looked at. I think I will take her for a drive and finish up the half tank that has the Lucas in it.

Looks like a misfire in at least one piston as the tester is letting off the throttle(maybe timing, maybe plugs). I'd get that exhaust as hot as possible before bringing it in. Do you have the newer ( blue top) EGR regulator(prolly wrong name). My old green top opened the EGR too slow. The blue top opens too fast/early. It might help route those unburnt fumes back around for another try sooner. JMO

I will have to check the ERG, I am not sure. One thing I did notice as I was dicking with the water cause misfire, when I unplugged the TPS the idle smoothed WAY out. Ran and drove fine, minus it would not down shift obviously. How are you figuring that it appears to be misfiring when letting off the throttle? (always up to learn something new)

Plugs and wires are easy enough, I did notice that the wires that are on it are super thin. Not sure if they are factory, but they are the thinnest plug wires I have ever seen.

[edit]
Also, she has a fresh oil change that was done last week (less than 100 miles ago) with Mobile 1 0W-40 with a Napa Platinum filter.

HEY! The edit button is back!
[/edit]

 

[gsi18867]

Probably a bad assumption but the hydrocarbons spiked at slower speeds and while reducing speed and coasting. HC count nosedived when he was hard on the gas, or when the slope of the speed line is the most steep. It looks like the biggest changes occur in at the bottom end of 2nd gear. But Kurt has a lot more experience with this. Im just reading graphs.

 

[IoN6]

In my searches on here, I see fuel pressure mentioned. I have noticed from time to time what I assume is the fuel pump make a super loud semi-grinding sound. I also noticed this at the fuel rail when I changed the oil last week.

 

[landtoy80]

In my searches on here, I see fuel pressure mentioned. I have noticed from time to time what I assume is the fuel pump make a super loud semi-grinding sound. I also noticed this at the fuel rail when I changed the oil last week.

Mine was doing the same thing, thus why I removed the fuel pump on other post.
I found that the vacuum hose from the charcoal canister that goes to the VSV was disconnected. I assume that the CC was not being evacuated fully as there was not enough vacuum. I also assume that when the CC was full, the noise was from the CC trying to vent the tank.
I am just guessing as I found the disconnected hose yesterday and have not driven enough to see if noise goes away.

Check all the hoses under the intake plenum.

The vacuum leak might of been why I didn't pass emission test.

 

[Pin_Head]

CO comes from a rich mixture: either too much fuel or too little air. Misfiring produces HC, not CO. Look for leaky injectors, a clogged air filter or leaky air pipe between the MAF and the throttle. There are other possible causes listed in the FSM.

 

[IoN6]

Well, I went by a stealership and picked up new plugs. My ESP must have been working because I told myself I would not pay more than $5/plug and they ended up being $4.7something. Put them in and a new air filter (had a K&N in it :/ ) and she idled like a dream! Got a little over excited and took her by for another run at emissions...

She failed. Slightly worse this time.

HC = 2.1565 (2.5 max / 2.2532 previously)
CO = 53.9329 (25 max / 51.8463 previously)
CO2 = 731.5868 (682.4043 previously)
NOx = 2.1617 (4.5 max / 1.9088 previously)

The intake is all snugged up, so now I am looking through the FSM to troubleshoot the TPS. When you flog it, it almost dies. And as I mentioned when unplugging it the idle smooths way out and slightly up.

Shot of the plugs, crazy discrepancy on the gap. All were over .031, two were over .04. 2,3 and 4 were not tight at all in the head.

6 --> 1

 

[IoN6]

Looks like a misfire in at least one piston as the tester is letting off the throttle(maybe timing, maybe plugs). I'd get that exhaust as hot as possible before bringing it in. Do you have the newer ( blue top) EGR regulator(prolly wrong name). My old green top opened the EGR too slow. The blue top opens too fast/early. It might help route those unburnt fumes back around for another try sooner. JMO

The EGR valve is a "green top"...

 

[gsi18867]

The EGR valve is a "green top"...

EGR modulator

 

[IoN6]

EGR modulator

Even though NOx is well below the max?

 

[ajax1]

Check your timing?

 

[Ridgerunner78]

Sub'd....

No constructive input but I just failed Colorado emissions for only high CO too. New plugs, wires, cap, rotor, air filter, recent oil change, timing @ 3 deg, and blue top EGR modulator recently installed that fixed my CEL for an EGR code.

 

[IoN6]

Sub'd....

No constructive input but I just failed Colorado emissions for only high CO too. New plugs, wires, cap, rotor, air filter, recent oil change, timing @ 3 deg, and blue top EGR modulator recently installed that fixed my CEL for an EGR code.

My gut is telling me the TPS, found the test procedure in the FSM. Going to check it tomorrow and see. Also found the procedure for the EGR and will test that too.

 

[Pin_Head]

As you found out, spark plugs aren't going to have anything to do with rich mixture. This is either too much fuel or too little air. Spark / timing has nothing to do with this. Read the FSM for solutions.

 

[gsi18867]

Sub'd....

No constructive input but I just failed Colorado emissions for only high CO too. New plugs, wires, cap, rotor, air filter, recent oil change, timing @ 3 deg, and blue top EGR modulator recently installed that fixed my CEL for an EGR code.

What code did you see previously? With the blue, Im seeing p0402-EGR flow excessive detected. Before, it was p0401-EGR insufficient flow

 

[IoN6]

As you found out, spark plugs aren't going to have anything to do with rich mixture. This is either too much fuel or too little air. Spark / timing has nothing to do with this. Read the FSM for solutions.

I downloaded a 1993 FSM from the site (this site), but the navigation of it is *ahem* tedious to say the least. I am starting to think it is incomplete too. I'll keep searching through it, but if you know a page or section off hand it would be greatly appreciated.