Ctenosaurian

So a bit of an update. Checked and replaced most of my vacuum lines tonight. Everything seemed to be connected properly. I pulled out the EGR and it checked out ok, although the line from the EGR to the EGR modulator was totally clogged. I cleaned out the clog in the line and on the modulator where the line attaches and it flows freely now. I am hoping that this with the new O2 sensor will help take care of my smog issues. I still need to go through the TPS and set my timing and idle, but it was nice to discover and solve the issues that I did tonight.

854x4

What were the numbers on the smog test? High HC and CO usually means ignition misfire and/or running rich. Having a exhaust leak upstream of the cat will make hc go down and nox go up because of the way the cat works but depending on how big the leak is the smog machine could show a dilution error and the test will be aborted but you will still be charged. For this type of failure you should start with Any stored fault codes- compression test to make sure engine is in good condition-check ignition system and timing- fuel system and pressure- vacuum leaks- o2 sensor- and finally cat. Also make sure your cooling system is working properly if the engine is too cold or hot it can affect smog results. Theres more to it but thats the basics and how we usually diagnose smog failures in california.

Ctenosaurian

They were high on both HC and CO. I had a O2 code so I pulled the sensor and it was completely covered in black soot, so the engine has been running rich for a while. I replaced the O2 sensor and the cat, because the cat was the original and was also coated in a thick layer of black soot. I checked and replaced most of the vacuum lines and like I mentioned the hose from the EGR to the EGR modulator was blocked. Next on the list is to check the TPS and then adjust the timing and idle.

Gamefreakgc

There's a few ways to check for an exhaust leak that I use. One, is to grab a length of hose and put one end in your ear and use the other end to "search" for leaks. Look for around joints near the header and along the exhaust pipe. You'll hear a hissing noise or a rush of air if you've got one.

The other method is to use Seafoam as directed by sucking it up the brake booster line and let it sit. When you start it up again, use a flashlight to look for any white smoke leaking out from around the headers or the exhaust pipe. You'll also clean your engine a bit in the process.

Ctenosaurian

Thanks for the help, I have a can of Seafoam that I have been meaning to run through the engine, so I will go ahead and do that tonight. I have read that it is good to replace the spark plugs after doing this, is that correct?

Gamefreakgc

I did a major cleaning as outlined by TexasAce here on the forums. It involved several treatments of Seafoam, water, and even some Mystery Oil through the gas lines. I pulled my sparkplugs on some work I did and they looked perfectly fine, grey-ash color (mine were fairly new). If you need new plugs anyway then do it. Otherwise don't bother. The FSM recommends the NGK V-power plugs, gives two contact surfaces for a spark.

You'll be able to tell if you need them. If after the Seafoam you have trouble accelerating or feel "resistance" when trying to rev to high RPM's, you need new plugs. Bear in mind that Seafoam has been around for 70+ years and they have a good product, so this is not likely.

Ctenosaurian

Ran some Seafoam through the engine twice last night, lots of black/gray smoke, so should be a bit cleaner now. I also put some MMO in with the oil, so that should help as well. Might do another round of Seafoam tonight to see if there are still deposits to clean out.

Gamefreakgc

A word of caution about oil: I've heard mixed reports about putting additives in the oil. I did end up putting MMO in the oil but got a oil change 500 miles later. It does run the risk of cleaning too well, freeing up deposits that could float around in your engine and cause damage. I'd recommend getting an oil change a bit sooner than you normally would, just in case.

Did you see any exhaust leaks?

Ctenosaurian

Thanks for the warning. I was planning on changing the oil again shortly as I figured that all of the gunk would contaminate the oil. Will probably do it after my next tank of gas. The only exhaust leak I saw was the one at the Cat, although it was tough to tell as smokes from that leak was coming up through the engine bay due to the wind. I am going to fix that leak and check again.

Co_94_PU

iTrader: (-1)

I think the best thing you can do before a smog test is a full proper tune up, eg don't forget to change out the oil. If you don't do alot of interstate travel you will have lots of nasty stuff that comes out when they bring it up to speed.

The code 11 "Switch signal", means the ac was ON, the tranny was in gear and someone steped on the gas whie it was in diag mode. Pull the A/C fuse, and it shouldn't reappear unless there is a short in the system. You can test those three switches per the manual.

Ctenosaurian

Co_94_PU - Thanks for the description of that code. I will pull that fuse and see if it comes back.