Just bought another 3rd Gen 5.7L Z28

[96RS Alex]

Re: Just bought another 3rd Gen 5.7L Z28

Do you have print out of your smog test?

Post it and maybe we can help you sort it out.

Sure do and really appreciate the V8 help!


So I have the entire weekend to wrench on this temporary problem and perform the following basic maintenance parts swap:

Spark Plugs ( YOU tell me which ones are L98 350 TPI decent? )
Cap
Rotor
Ignition Wires
PCV Valve
Coolant Flush
Thermostat ( 180* or stock 195*?)
Gatorback Poly V-Belt
Oil Change + Filter ( going Mobil 1 Synthetic VS Valvoline )
Fuel Filter
K&N Air Filters ( done )

I won't mess with the EGR valve yet but my O2 Sensors are in question and I'm not afraid to change them if it would definitely help me pass the next test. I just need your opinions about the Hydrocarbons PPM & CO% readings shown at the top of this post. I'll state that this is an original Dual Catted exhaust with a Flowmaster Cat-Back setup ( original GM catalytic converters ).

A deeper 'Search' in other L98 related websites mentioned using denatured alcohol to raise my chances to pass this test or mess with the timing. I can do the denatured alcohol bit but how much if any of you used this trick? I still have 3/4 of a tank of 87 plus Seafoam, should I expel all that and refill with 93 Super Unleaded?

Newbie Question #1: Would you Seafoam an 88K mile motor?

Newbie Question #2: When's a good time to replace the catalytic converters?


I'm being real here, the previous owner was a cop and didn't mention doing anything else besides an oil change and I did ask him about the rear and transmission fluids and he said "it's all original".
So with all that information, I have much to attack later.

[transamtom1]

Re: Just bought another 3rd Gen 5.7L Z28

Well emissions is like a three legged stool,HC,CO and NOX.

By the look of it you have unburned fuel HC and CO and not much NOX.

Change the plugs and wires and oil, use synthetic it doesn't burn and use a 195 T Stat to get your combustion temps up(more Nox).

Get an adjustable fuel pressure regulator and decrease the FP to lean out the mixture.
= more NOX less HC and CO.

Good luck

[ACiFiC]

Re: Just bought another 3rd Gen 5.7L Z28

Wow looks amazing, how many camaro's do you have? lol

[venom3300]

Re: Just bought another 3rd Gen 5.7L Z28

looks like it was taken care of, grats!

[96RS Alex]

Re: Just bought another 3rd Gen 5.7L Z28

Wow looks amazing, how many camaro's do you have? lol

I have 4 now. '92 25th Anniversary Z28, 35th Anniversary '02 SS, 1996 3.8L M5, '88 Iroc Z28 & 1 Pontiac T/A LG4 305 4BBL. So that's 5. I'm gonna sell the T/A and Iroc Z28 after I fix them. Something about black Camaros...

[96RS Alex]

Re: Just bought another 3rd Gen 5.7L Z28

I hardly pay attention to the Service Manuals to these vehicles but apparently even in 1992 these Camaros were designed to run on 91 Octane or higher.

[DAS BOOT]

Re: Just bought another 3rd Gen 5.7L Z28

Nice I am dieing for a 3rd gen....

[Red&Black_Attack]

Re: Just bought another 3rd Gen 5.7L Z28

Another helpful tip, dont shut the car off before you get it inspected. I did this when I had my GTA... Used 93 OCT and added smog/emmissions additive and ran it thru and went and got it inspected.

Didnt shut the car off until they inspected it and it passed. Texas is strict btw.

Hope that helps. You got a nice ride, I love 3rd gens. There my favorite. :)

[venom3300]

Re: Just bought another 3rd Gen 5.7L Z28

is the 3.8l suppose to use the expensive stuff too???

[SixShooter'00Camaro]

Re: Just bought another 3rd Gen 5.7L Z28

Gorgeous car man! I don't think you should sell any of them, you have quite the amazing collection.

[DAS BOOT]

Re: Just bought another 3rd Gen 5.7L Z28

is the 3.8l suppose to use the expensive stuff too???

no unless you tuned your car to specifically run it, or increased your compresssion.

[whitdog54]

Re: Just bought another 3rd Gen 5.7L Z28

87 on a 3.8, unless like said you have power adders FI or n20 and are tuned.

Car looks amazing! great pick up, impossible to find a good 5.7 too, and none of the bumpers have clear coat peel!!!!

Goodluck, enjoy it

[96RS Alex]

Re: Just bought another 3rd Gen 5.7L Z28

Update: ( I love tech talk don't you? )

Failed my 2nd test after replacing all the mentioned parts above, even the O2 sensor. I put on at least 100 miles of break in cruising since this past Sunday BUT I did manage to pass 2 out of 3 now, so I'm making some headway at least.
Below is the emissions test from today. Better than the first test!


I did not touch the EGR, Catalytic converters or mess with the timing yet. The timing part I need direction on as I dont have a timing gun, scanner or oscilloscope style diagnostic equipement on hand. I have yet to figure out the adjustable fuel pressure gauge setup. Maybe someone can address the how-to deal on that part.

I also suspect the cats being 20 yrs old could be preventing me in a clean pass but any ideas would be helpful.

The fuel tank is full of Super V Power 93. Still it failed but not losing hope yet! Someone in the waiting room recommended I should try a different testing center and on a hot day to improve my chances of passing. I have also heard of using denatured alcohol or STP dry gas additive also. Worth a shot?

They put a fan on this time in front of the '92 Camaro.


Below is from the FIRST emissions test to show my intial test. What's next for me? I'm thinking what might include retarding the timing for a leaner mixure since I'm running a tad rich. Variables tend to confuse me but one adjustment at a time for me.


Went with Bosch Fusions. ( I do experiment between brands )

[96RS Alex]

Re: Just bought another 3rd Gen 5.7L Z28

I think I'm gettin carried away with V8 tech stuff and pics on a V6 forum ( apologies to the Moderator ) but I'm including a shot of my V6 in the background as well. Thanks to those who gave compliments and advice on my L98 motor!

[96RS Alex]

Re: Just bought another 3rd Gen 5.7L Z28

Another helpful tip, dont shut the car off before you get it inspected. I did this when I had my GTA... Used 93 OCT and added smog/emmissions additive and ran it thru and went and got it inspected.

Didnt shut the car off until they inspected it and it passed. Texas is strict btw.

Hope that helps. You got a nice ride, I love 3rd gens. There my favorite. :)

I will run the Z28 as long as possible, I ordered a sensor and harness related to the cooling system to help me do that.

Texas is pretty strict! Here are your smog limits:

HC 148 ppm
CO% 0.83
NOx 1014 ppm

I would've passed in your state but no, CT has to be anal about it.