1997 camaro with 3.8 almost failed smog. Does this look like the cat?

jeffp1167 · 08-26-2009, 05:40 PM

I bought this car brand new so no mods have ever been done to it. Car has no DTC's present & runs/idles perfectly. The only things ever done to this car are 2 drive belts and 1 transmission service. However it has never had a tuneup. The smog guy says this could be the reason and before you say wow never had a tuneup it was designed so they say to go 100k before it first tuneup which I must say it did. It is at 112K now but being it runs so good I dont see how these readings could be tuneup related.

HC's
15mph max 52 average 9 measured 51
25mph max 36 average 7 measured 17

CO%
15mph max .49 average .02 measured .03
25mph max .46 average .03 measured .00

NO
15mph max 424 average 57 measured 120
25mph max 711 average 58 measured 167

It's the 15mph HC's that were where it almost failed. But eveything else was high as well. Two years ago it ran equally as good and no performance differenced have been noticed but was wayyyyy cleaner. I've also heard a previous gross poluter car can heavily contaminate the sniffer and if another car is tested right after it can cause the next car to fail as well.

OH and dont even bring up cash for clunkers cause thats not going to happen with this one.

angel71rs · 08-26-2009, 08:45 PM

I know the GM plat plugs installed on LS1s in those years have little pucks on the ground electrode that have a habit of falling off. This results in a huge gap, makes it harder for spark to jump the gap, initiate ignition. One 98 I changed the plugs on had half with missing pucks, ~50k/miles on it. Engine seemed to be running fine, but after the plug change, felt like it picked up 20-30 hp.

If the same plugs were used on the 6s, your smog guy is probably right.

jeffp1167 · 08-27-2009, 06:26 AM

Quote:

Originally Posted by angel71rs

I know the GM plat plugs installed on LS1s in those years have little pucks on the ground electrode that have a habit of falling off. This results in a huge gap, makes it harder for spark to jump the gap, initiate ignition. One 98 I changed the plugs on had half with missing pucks, ~50k/miles on it. Engine seemed to be running fine, but after the plug change, felt like it picked up 20-30 hp.

If the same plugs were used on the 6s, your smog guy is probably right.

all I know is it is supposed to have platinum according to books. But wouldn't the ecm detect some sort of a miss fault code?

angel71rs · 08-27-2009, 11:02 AM

Yup those factory installed "100k" plats are crap. The 98 with the 1/2 missing pucks wasn't throwing any codes, felt like it was running good. I just did the plugs cause of all the threads I read about the factory plats being crud. Not only did power improve, so did mileage, and I was able to put it in 6th a few mph lower and have it pull the gear smoothly.

The PCM is programmed for a certain threshold before throwing a misfire code, won't pop the code for just any misfire. Another possiblility is leaky injectors. You can put a pressure tester on the rail and see how quickly pressure bleeds off to test for that. Plugs are cheap, cats are $$$, another reason to try plugs/wires 1st.

bradNTx · 08-27-2009, 09:19 PM

I'm surprised you never had any misfire issues since 97. Go ahead and get yourself some new plugs and wires, give yourself plenty of time for the swap since this will be your first time. Stock replacements are overpriced just get yourself some NGK's and rock on.

jeffp1167 · 08-28-2009, 05:41 AM

Quote:

Originally Posted by bradNTx

I'm surprised you never had any misfire issues since 97. Go ahead and get yourself some new plugs and wires, give yourself plenty of time for the swap since this will be your first time. Stock replacements are overpriced just get yourself some NGK's and rock on.

Nope this car has been a really good car. It's not a tradionally abused f-body though thing still looks new in all aspects. So original still even has the factory shocks on it ... Yeah I know they are wayyyyy past changing.

OutKlast · 08-28-2009, 08:28 AM

Quote:

Originally Posted by jeffp1167

all I know is it is supposed to have platinum according to books. But wouldn't the ecm detect some sort of a miss fault code?

I have a 1997 3.8, car started jumping around and acting weird. Zero codes till it got REALLY bad then I got some random misfire codes. Turned out it was the coils. The Coils on these cars tend to go bad, good news is they're easy and cheap to fix. You can also just check the coils for corrosion. In my case one set of coils was pretty well corroded.

There may be some way to check if the coils work, but you're at 112k and all 3 coils will set ya back maybe $70 bucks and 20 minutes of your time. I'd do it just as preventative maintenance at this point.

bradNTx · 08-28-2009, 10:13 AM

Quote:

Originally Posted by jeffp1167

Nope this car has been a really good car. It's not a tradionally abused f-body though thing still looks new in all aspects. So original still even has the factory shocks on it ... Yeah I know they are wayyyyy past changing.

Well then plugs should probably be done at the least, hoenstly I wouldn't worry about coils until you get a misfire code. Give yourself plenty of time as they aren't exactly easy to get to.

If you have never done it before here is the easiest way I have found to get them out.
You can remove cylinders 1,2 from the top with a spark plug socket and 3 inch extension.
Cylinders 3,5,6 are done from the bottom. On 3 I used the socket and a wrench, on 5 and 6 you should have room to use the socket and ratchet.

Cylinder 4 is the tricky one. You start under the car sliding a socket with 3 inch extension attached over the spark plug, then from the top you'll be able to slide a universal joint and another extension into the 3 inch extension and break it loose that way.

My 98 has about 140k miles and I have changed the plugs 3 times.

If you decide to do wires also take your time as there are a bunch of wire looms and clamps which hold the wires in various places to keep them from burning on the exhaust.

Raven02TA · 08-31-2009, 08:22 PM

OP mentioned that it was Designed to go 100K before a tune up.... yes they were designed for it but not recommended for it. Just because they say it can go that long doesnt mean you should. by not doing the tune up you are effecting a NUMBER of things that could have caused you to almost fail. and next year you probably will

not doing the tune up this long will result in improper fuel burn in the cyl. which yes will result in extra carbon build up, in your cats, your egr valve, and on your oxygen sensors. which over time will slowely cause to run like ass, and of course make poor gas mileage.

my recommendation would be change the plugs and wires. best to buy an NGK plug, either an NGK iridium or a standard will do just fine, gapped to the factory spec. change the fuel filter, and also pull the EGR valve and clean the carbon out of it (use electronics cleaner or standard carb cleaner) as well as change the oxygen sensors.

doing this will result in your gas mileage picking up. the car will run and feel much better by the seat of the pants. and also next year you will pass emissions much easier.

jeffp1167 · 09-01-2009, 09:48 AM

I had the cat replaced and then the car was pretested and was very low on its emmisions again. Basically now it reads right around all the averages. I will have it tuned up when I get a chance again though. But first needs shocks in a bad way as well as other more important stuff.