IrocTheZ28

Getting down to the point here, I recall the previous owner said it'll pass emissions, well today it failed but not by much as the pics below show.

Last night before the smog test I added one can of Seafoam to a full tank of 87 regular unleaded. This morning I went out for a 50 mile cruise/ drive like hell style driving to "light the cats" fully and drive towards the test center. Upon arrival, they rolled the rear wheels onto what looked like a dyno roller.

After the emissions test completed, the inspector asked me why it was running hot. I replied that it hasn't overheated since purchasing the Camaro but that I'd look into it further. I get home and I notice the coolant recovery tank has evidence of dried coolant that may have puked a long time ago but to me it runs beautifully with no problems. Seems to me the angle of the rear wheels being jacked up so high onto the rollers may have burped the coolant but I'm not sure.


So I have the entire weekend to wrench on this temporary problem. A 'Search' tells me I will perform the following basic maintenance parts swap:

Spark Plugs ( YOU tell me which ones are L98 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?

Newbie Question #3: Are the O2 Sensors located down past the exhaust manifolds? I can't see the passenger side sensor yet but I saw this sensor which is on the drivers side below. How hard are these to swap out?


I hope I explained & displayed all this thoroughly in detail so I'd like to get some ideas thrown down on the table here. I love this 25th Anniversary 88,000 mile '92 A4 Z28 and want to get it back on the twisty roads here in Connecticut. An emissions friendly test center recommendation would be cool too for those who reside in CT.

IrocTheZ28

More Pics:

hartman

iTrader: (6)

I wont be that much help as i dont know much about the emissions as i have never had to deal with it but, The o2 sensors can be a reallllllll pain if they are rusted in pretty good. All the tune-up stuff would be good if it hasnt been done in a while if at all? And napa has a 10% mail in rebate on tune up stuff which would cover pretty much everything you need even the O2 sensors if you did change them. Somone else will chime in on to what will actually affect your emissions test but if none of the tune-up items have been done its still a good idea to change them.

hartman

iTrader: (6)

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

never hurts to seafoam any motor.

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

usually when they go bad which shouldnt be till over 100k

Newbie Question #3: Are the O2 Sensors located down past the exhaust manifolds? I can't see the passenger side sensor yet but I saw this sensor which is on the drivers side below. How hard are these to swap out?


and from what i looked up there is only 1 o2 sensor before the cat.

M G Brewer

im soo glad the state i live in dont care what u drive.

miatanut5

Judging by your numbers, I'd say it's running a bit rich. I would agree about the full tuneup, that's the first thing I would do. On these cars there is only one O2S on the driver side.

knight123

iTrader: (4)

mine failed first time as well, did the tuneup thing and 02, drove it back and it passed. Mine had 135k on the catalytic so unless it melts you should be good i would think. Check the base timing also since that can cause a rich condition if spark is late. If the 02 is reading wrong it will also cause you to run rich, on these cars it is a part that needs to be replaced if it gets full of carbon, you also can't clean them. mine was $18.00 at autozone.

i noticed a definite change in exhaust smell afterwards.

fireburdluvr85

another ct person? nice car btw. wish id passed but my old tbi set the standard of failing.... never smoked and got excellent mileage but the test station required it to be in drive for the test? wasnt a happy camper. id stick with the stock 195 to keep the emissions part of the computer happy. it needs the heat to hold in closed loop operation. you barely failed so just a good tune up ie, ignition components, oil change, set timing, set tps, set idle speed, o2 sensor, and clean your throttle body if you havent yet. i do that at work on all our vans when its time for emissions just to give them the final ump to pass. havent lost one yet. lol all the info is on this site for those procedures but itll ensure you run as close as a new engine as possible. if you pass , pass on where you went. i may know the shop seeing as i lived down that way for yrs..... now if only id take my car in for another test since i put in my new drivetrain...

DENN_SHAH

iTrader: (1)

very nice car!

your car is actually running cleaner than the standards it had to pass back when it was new. IIRC, the federal requirements in 1992 were 220 ppm on HC and 1.20 % on CO, but i could be wrong.
when i was having to get my car tested, and later on when i was doing state inspections, i watched the limits continue to drop year after year.
the first time it had to be tested, the limits were 220 HC and 1.20% CO.
IIRC the last time mmy car had to be test the limits were 120 HC and 0.80 CO.
i forget what NOx was, i think up around 1200. the last time was around 650 or so.

going by the NOx, the EGR system appears to be perfectly fine. 425 is low.

with the mileage and age of the car, i would say the cats are probably a little on the weak side but not necessarily bad and i would be hesitant in replacing them because the after market cats don't always work very good. some after market cats will do fine for HC, but don't work good at reducing NOx.
others do good for NOx but don't reduce HC or CO like they should.

the part you have pictured is the O2 sensor. they get start getting weak after a couple of years, so changing it shouldn't hurt.
you'll probably need a special socket to change it as it is a PITA to get to plus they trend to get stuck after being in for a while. use an A/C Delco
O2 sensor to replace it.
an oil change never hurts.
on the plugs and PCV Valve, use A/C Delco and stay with the stock 195 T-stat.

normally pulling 1 or 2 degrees of timing will help drop both HC and CO. if
you pull too much, both HC and CO go up.

Damon

You're on the right path.

Get an O2 sensor socket (deep socket eith a cut down one side for the wires to hang out of) and about a 1 foot long extension to R&R the O2 sensor. A good overnight soak in PB Blaster (penetrating oil) and it should come out without too much difficulty.

Also definitely check the factory base timing (with the timing wire disconnected). It's common to bump them up for a little more power but it hurts emissions. Dial it back down to the factory 6* setting (or even a little lower) and it will help with the sniffer test, then bump it back up when you get home.

IrocTheZ28

Changed the O2 Sensor. The tool to remove it was more expensive than the sensor. That sensor was a SOB after a few squirts of Kroil Penetrant & a breaker bar.
Replaced cap, rotor, coil, plugs, wires, fuel filter, oil & filter & serpentine belt. Fun job!


Also went with these Bosch Fusions ( I do experiment between brands ) All plugs were like the old one you see on the left, so far so good.


Few more questions:

I discovered a new problem. Between plugs 6 & 8 there is a semi corroded sensor and the harness was dangling with a corroded female connection. It's above the knock sensor. I think it has to do with my fans coming on at 'Start' before 'Ignition'. What is it exactly and is there a kit to replace both? Looks like I have to use more penetrant to remove that sensor from the block and splice a new connection from the old harness.

The engine cooling system will go through an basic overhaul. Coolant is reddish brown so flushing it is not a problem but I'm ordering the following parts: Radiator, Thermostat 195*, Hoses & Heater Core.

Is the L98 water pump reverse rotation or not?

Damon

That's the coolant temp switch that activates the second fan on a dual fan car (TPI). The second fan is not controlled by the ECM or A/C system- only that switch. And it's turn-on temp is very high- like 228*, if memory serves. It's a common upgrade to buy an aftermarket replacement with a lower turn-on temp. One of the little tricks that guys use on these cars to help keep them running a bit cooler in stop-and-go traffic on hot days.

It screws into the water jacket on the cylinder head so it would be best to replace it while you have the old coolant drained out. Also, you can buy a replacement pigtail with the correct kind of connector on the end at any good auto parts store. Just ask them for their specialty electrical connectors catalog. That plug is identical to the one on your knock sensor, so you have a visual reference.

Yes, your water pump is a reverse rotation style pump. Anything that is driven by the back side of the belt (flat side) is reverse rotation. And there's no reason to pay big bucks for an aftermarket water pump- the stock ones are more than adequate for everything but the most radical of engines. A good rebuilt unit from a reputable supplier (not Pep Boys, Autozone, etc.) is all you'll need.

I'd pass on doing the heater core until it actually starts leaking. They are quite a PITA to do. I've found that just back-flushing a stock one will do wonders making them flow again (if you aren't getting much heat from your heater). Just use a garden hose on full blast to force water through the heater core lines in the REVERSE direction from how it normally flows. Literally just jam the garden hose end onto the end of the heater core return hose and hold it there for a while. Wait till you see the crap that flows back out the inlet hose! Again, this is only if the heater core is getting obstructed, not if it's leaking. Leaking = replace.

fireburdluvr85

you can get the napa fan switch for an 87 grand national. i believe its part fs113. its a direct replacement. think it cost under 40 bux but has a 2 day wait to get from jersey. thats the one i have and it never goes over 204* before it turns on at idle. my stock one when i got the car didnt turn on till 238* or something. too bad you weren't closer cause i have that sensor socket. got it at harbor freight for 5.99. i dont mind helping a fellow thirdgener.

IrocTheZ28

Damon, I have never tried timing before on a L98 TPI. What's involved in the procedure? Do I need a timing gun?

IrocTheZ28

Hard to type on a Motorola Droid smartphone here lol, to those other CT 3rd Genners I'm by Tweed Airport. Would be cool to gather after this rainy forecast!

Got one more nagging question: Do I have aluminum heads on this L98 '92?

Thanks to all to helped, very much appreciated.

IrocTheZ28

Update:

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.


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 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!

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?

Tommy R

I live in CT too. What i used to do with my 86 roc is run a tank with the product "guaranteed to pass" after i ran down the tank i would put in 4 dry gas bottles and fill it up to a quarter tank. It always passed, sometimes barely but it passed.

Tommy R

Also try a different test facility, you may get a different reading i use the valvoline oil change and emmisions testing

ASE doc

You're still just a touch rich. Check timing and retard it 2 degrees from where it is. to set timing: Run the engine til warm, shut the engine off, disconnect the timing connector which should be above the AC housing on the firewall. It's a tan/blk wire with a weatherpack in line connector. Connect the timing light, restart the engine and set timing. Shut off the engine, reconnect the timing connector, disconnect battery for 30 seconds to clear code 42. You're finished. Retarding timing reduces emmisions by increasing exhaust manifold temp. For this to work, the exhaust has to be hot. To keep the exhaust hot, run the engine at 1,800rpm while waiting for the test. This also keeps your cats lit.

Am I right to assume that the testing in CT is done by independant shops? The shop's equipment may be inaccurate. Try a different shop. Those numbers are very tight. Here in Oregon, its CO- 1.00%, HC- 220ppm. Much easier to get even old cars through.

ASE doc

BTW, I understand the urge to try different plugs. I used to run Bosch Platinum in everything. Today, I use whatever the car came with in everything. GM engines were designed with AC Delco plugs. Anything else will not work as well as the OE plug brand and number. I have almost never heard of anyone not having issues with the Bosch +4s.

IrocTheZ28

1) Only a handful of independent shops participate in the CT Emissions Program. Others don't for liability reasonsI assume.

2) Excellent advice, I will look for the timing connector. Just trying to get time off from work to speed this to resolution.

Any merit to flushing these 20 yr old injectors by the fuel rail and what benefits I may see out of it? Videos or pics would be helpful too. The Z28 purrs nicely after coil, cap rotor, plug & wire swap.

No rotten egg smell but someone please link me a site for decent replacement catalytic converters. I have the original dual cat setup.

oH HorizoN

I haven't read the entire thread, but I'll just tell you what possibly the two most important things are in order to pass emissions:

Get a new cat. I bought a high-flow one from Edelbrock I think.
And before you go to test, say 50 miles before, add as pure as you can get isopropyl alcohol and add about a quart to an almost full gas tank. I know you did seafoam, and that's great, I use it too, but I've always used alcohol when I go to emissions. Just an insurance policy, so to speak.

I'm not saying you shouldn't do the o2 sensor or plugs or whatever else - but WHATEVER you do, do the cat. If that cat is over 2 years old, it's crap. The older it is, the worse it is.

EDIT:

Here's a link to get started on Cat's, I guess.

http://www.summitracing.com/search/D.../?autoview=SKU

I got high-flow because, well, I hate restrictions, but I have heard that OEM cats have LESS restriction that any aftermerket one... feel free to do your own research and do what you want. Hell, clamp a cat on there, and after the testing is done, straight pipe it, but I highly suggest a brand new cat! That in itself may do it for you, as you are already passing the NoX category.

ASE doc

Cats crap after two years? That's quite a base assumption. I see some go for several years and still function well. With such tight standards, new cats may be necessary, but I wouldn't go there without first working with adjustments.

Any injector service done "on car" will be of limited effect. You can do just about as well with a can of seafoam in a tank of fuel over three successive fill ups. Your are so close though. I have had some improvement using the Motorvac Injector cleaning system. If you have an extra $125 to spend you may want to try it.

oH HorizoN

From what I have read in a few different books, catalytic converters lose much of their effectiveness after two years, yes. One can only assume that it is only compounded as the years go on, especially if a motor has ran hot, rich, or anything like that for a period of it's life.

All I know it, I replaced the cat in my Camaro, which APPEARED to be the original one... 20 years old at the time. The test results before and after were shocking, to say the least.

ASE doc

20 years is a long time. Much of a converter's longevity depends on how its made. The catalyst ingredients that go into a cat are very expensive. Better quality cats, like the OE, contain ample quantities of, paladium, platinum and rhodium. These compounds are all precious metals and are each costly.

Cheap universal cats, most commonly used for replacement of failed OE converters, contain smaller amounts of these these expensive ingredients and make up the difference by enriching the wash coat with extra paladium. While the wash coat allows the replacement cat to meet required standards for function, the wash coat doesn't last very long. Generally within two years the cheap converter has lost half of its efficiency.

OE, converters are engineered to last at least 80,000 miles.(the federally mandated emmisions warrantee) Many last much longer than that, depending on how well the vehicle's tune is maintained.

One thing to mention here, on car injector service can be very hard on the converter.

oH HorizoN

Hmm, I was not aware of the staggering differences between OE ones and aftermarket ones. This is good to know.

You, sir, you are one I will be keeping an eye on. The more knowledge I can gather, the better.

DENN_SHAH

iTrader: (1)

muiltec injectors weren't the best when they were new.
the chemicals used in the flush are harsh and the insulation on the coils inside the injectors are old. so i would be worried about killing the injectors by flushing them. the most i would do for a flush on those old injectors would be a can of 44k in a full tank of gas.

i've seen many after market cats fail within 3 months/3~4000 miles, especially on OBD2 vehicles. you got to love P0420/30.
with the starting price of around 800.00 bucks and up, most people can't afford to buy factory cats, so they go after market.
if i were the one repairing this car, i would yank a little timing.
when a vehicle just barely fails like this one and the limits are so low, sometimes it can be a pain to pull out the last little bit without a little cheat.
2 professional wrenches have reccomended pulling a degree or 2 of timing, we did it for a reason.

does the report show O2 and CO2?

IrocTheZ28

I'm up late researching Speed Channels video on Catalytic Converters 101 http://www.catcoglobal.com/videos/sp...nel-video.html & can't decide which route I should go here with the cat system. Cost is no matter for now but I like the smooth bends I see on the first two. Yes, I'm keeping the Z28 for a long time. Future plans go for smog legal headers. Maybe another recommendation is needed for my dual cat setup.

Direct Fit. Made by Walker #16101 Dual Cat $397.79


Direct Fit. Made By Bosal #0795038 Dual Cat $410.79


Direct Fit. Made by Eastern Catalytic Converter #50206 $361.79


Or go with universal cats? I do have a Midas Shop nearby that does emissions testing as well.

So before I take my 3rd test, it seems to me that the cats definitely need replacing and I feel up to this task. I'm certain this will drop my emissions dramatically. Feedback appreciated.

Sidenote The Connecticut Emissions Program allows me to pay another $20 for a test and a free retest if it fails so I can correct the problem. While my hectic work schedule dragged this on for so long, my intentions were to fully understand how YOU would approach the fix so I can make an informed decision and I got more than I wanted so a big thanks to you all.

IrocTheZ28

Interesting stuff you mention. Btw, I just have this 2nd report available for now that only shows HC(ppm) / CO% / NOx(ppm)

Solders18

I would say follow what everyone else is saying and find a timing light or buy one and adjust the timing. a degree or two and you pass easy

ASE doc

Check timing and replace cats and you'll breeze through the test.

I see alot of Walker in the aftermarket. They manufacture cheap OE replacement exhaust parts. Their pipe is thin wall and their cats are the cheapest I've seen. Eastern is a major supplier of the cheap universal cats I was referring to. Can't say they would be any better than Walker. Midas will install cheap universal cats and may screw up your exhaust geometry in the process, leaving you with an exhaust "buzz".

I like the look of the Bosal, which appears to have mandrel bends and a decent Y-pipe. I would have it installed by a good exhaust shop. Or do it yourself.

fireburdluvr85

have to agree on the timing. its being stubborn. on a side note i used to work at the east haven monro and i have to agree with ase doc on the fact the walker was cheapo parts. we offered a warranty but only on the muffler or main component. the pipes always rotted out in less then a yr and you got stuck paying full price because we couldn't remove the component due to rust. cats had a 90 day warranty and i could never figure out why. watched to many people think they got a deal. 550 for a cat on say a 94 grand am..... just felt like they were stealing from people.