'88 Cadillac smog (Emission test) fails

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Hi all,

I went to do an emission test, but the '88 Brougham fails. It shows over 300 in HC ppm. The emission facility mechanic suggested to use guaranteed-to-pass-emissions-formula.

I heard that seafoam can help also. My question is that the car was sitting for a year with a full of tank, and I just purchased the car two weeks ago, so I need to pass the emission to register the car under my name. I am wondering if I put guarantee formula with already old gas in the tank would that work?

OR shall I empty the tank for driving long trip, then put fresh gas in with formula?

I also wonder if I can use seafoam in conjunction with the formula?

Your advice will be very helpful.

Thanks,
 
Move to NJ no inspection at all below 1996
actually guaranteed to pass and a long highway drie with new plugs and wires if needed is the best for that car
 
Originally Posted By: crazyoildude
Move to NJ no inspection at all below 1996
actually guaranteed to pass and a long highway drie with new plugs and wires if needed is the best for that car


lol, I wish we have the same here. The only years that exempt from E test are 1987 & under. Mine is 1988
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Here in Denmark.if a car has too high a carbondioxid level. It is a common used trick to drive the tankt almost emty. And fill it With a mix of 5 litre of ordinary 95 octane petrol( i know it is not called 95 in the US) and 1-2 litre of karburator alkohol(Isopropanol) dose after how much it is over the limit.

Work every time. But it is important that you fill the tank rigt after the test. Or you Will likely see ignition knocking and engine damage
 
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I am not familiar with emission testing, what are the rules? Does it have to pass what the exact powertrain configuration of the car was designed for in 1988 or does it have to pass other numbers i.e. average for the model year, today's emissions etc.

I am about to move to BC but they just dropped the Air Care requirement for my Chevelle which has me breathing a sigh of relief.

On to your issue... is the car in good tune? You should maybe give it a solid tune up (plugs, wires, cap, rotor, air and fuel filter) to try and get your unburned HC's down.
 
Does this cadillac have the oldsmobile 307 v8? If so, that engine has difficulty passing smog tests. There's one in my family. When the state of Texas started doing smog tests in i think the early 2000's maybe late 90's, there was a special bulletin regarding GM vehicles using that engine. It stated that they would not pass the emission test and to utilize a specific dyno test with a different MPH. My dads never passed unless he ran either berrymans or that RXP stuff in the tank.

Any car 25 years or older in Texas is exempt from emission testing so that info is now long gone.
 
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I'd find a way to run it out of the old gas and start anew. Burning it up would be the best way... are you on a temporary tag now so you can do it legally?

Seafoam would be good then go through with some new plugs and wires and a cheap oil change.
 
First check the spark plugs and wires.
Get rid of the old gas, do not emission test on that fuel. Run some fresh fuel through it and some berryman b-12, forget the seafoam its overpriced light oil with alcohol and some naptha.

After you run the fresh fuel and b-12 out, put some e 20 or 30 fuel and emmision test on that. put just enough e-30 to emission test, then fill up with regular fuel.
 
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Originally Posted By: spasm3
First check the spark plugs and wires.
Get rid of the old gas, do not emission test on that fuel. Run some fresh fuel through it and some berryman b-12, forget the seafoam its overpriced light oil with alcohol and some naptha.

After you run the fresh fuel and b-12 out, put some e 20 or 30 fuel and emmision test on that. put just enough e-30 to emission test, then fill up with regular fuel.


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And tune it up with fresh plugs and wires as others have stated.

CRC's GTP or Berryman's B-12 are both good cleaners.
 
I used to have a '78 Brougham. The only way to get it to pass smog was a new carburetor and new catalytic converter every two years. Finally the state offered to buy it for $1000 to get it off the road. It was a nice car and very dependable, but it was never intended to run as clean as California wanted it to.
 
Originally Posted By: momo
the '88 Brougham fails. It shows over 300 in HC ppm.

HCs are simply raw, unburned gas. It means raw gas is making its way through the engine and out the tailpipe.

These are the most likely suspects:
1) Secondary ignition system in poor condition (plugs, wires, cap, rotor)
2) EGR passages selectively partially- or wholly-clogged
3) Poor compression on one or more cylinders
4) Catalytic converter weak or cold

What are the OTHER numbers you got from the test? Emissions need to be taken as a whole, not just a single number in isolation.

How does the engine run? How does it start? How's your gas mileage? Do you have a carb or EFI?
 
As others have suggested, tune up and get rid of the old gas. I would add to that an oil change before any emissions test. No telling if there is fuel in the oil.
 
So for anyone who is wondering, the Oldsmobile 307 is one of the most temperamental engines i have ever dealt with. They are very durable and nothing seems to kill them. They run super smooth and they do not have any kind of exhaust note. Simply put, they were designed to be a quiet, no fuss engine.

They are blessed with a whopping 140 horsepower, fuel is mixed via a carburetor, and there is probably 1 miles worth of vacuum tubing throughout the engine compartment. You simply cannot "tune" one of these engines. Even with a full tune up it will probably fail emissions testing. This engine was never intended to live into the early 1990's with the introduction of stricter emissions testing.

Rumor is GM had a stockpile of these engines starting in the latter part of the 1980's and GM knew they would never build enough Oldsmobiles to deplete the supply. Instead of trashing the supply they went and put them in a wide variety of GM cars, paid EPA fines to legally sell them, and still saved money over trashing them. I've heard this story from multiple people in GM engine assembly.
 
I have a sales brochure I'll try to find thats for the 1989 Chevrolet Caprice. In the specifications it has a disclaimer stating that the engine may not be built by Chevrolet, but rather another GM brand. I'll try to find it and post it.

This angered a lot of people when they learned that their Chevy, Pontiac, Buick or Cadillac had an Oldsmobile engine. Soon after that GM Powertrain was established so they could use any engine in any brand. Also by incorporating all of the engine teams from all the brands, they could collaborate and put all their knowledge together.

Plus honestly, who wants to buy a Cadillac with an Oldsmobile engine? GM lost a lot of customer faith in those days.
 
is e85 available?

run old gas down low.
put a couple gallons of fresh gas in
run gas down low again.
put in a 3-4 gal of gas and a gallon of e85
take car on highway for 20-30min.. immediately go for emissions test.

Maybe regular tune-up type stuff such as plugs wires etc.
 
Yeah, it's unburned HC from a partial misfire. '88 will have ECM controlled Quadrjet and a ECM controlled HEI distributor. So you need to make sure that a few things are right.

I'd do new cap, rotor, and Moroso spiral core plug wires (ain't cheap, but they work well). I'd prolly run Bosch Platinum Plugs gapped at least 0.045". Iridiums gapped at 0.050" would be even better. Anything to light a less than perfect mix ...

Read up on looking for vacuum leaks and do a pretty good test to make sure they are well sealed. A vacuum leak can fool the carb, the distributor and the ECM and make things run bad.

Install a 195* thermostat for the test. Once do the test, you can drop back to 180* if need be.

Clean, new regular fuel, 1/2-3/4's of a tank, no more or it might start sloshing into the vapor recovery system and that can trigger iffy readings...

Add three cans of Berrymans B-12 to your tank now. Drive the tank dry and refill. Put one can B-12 in when you fill with fresh for the test.

See if you can lean the idle screws a bit...

Fresh oil and filter change. I'd run Delo400 15W-40 LE for the test and leave it for the summer. Then move to whatever rows your boat...

Take it to an independent dyno tune shop with a tailpipe sniffer and have them adjust carb for least HC readings. Have them check the timing advance to make sure it's hitting targets ...
 
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All engines have enormous amounts of HC, CO, NOx coming out of the exhaust & the catalytic converter converts them down by storing O2 & reburning/breaking down into CO2 & H2O. What are your other gas readings? You can tell a little as to why HC's are high based on other gas levels. For example, If O2 is high, you can have a partial misfire with high HC & CO readings. Can you post the levels for the other gases?
 
Originally Posted By: stower17
I have a sales brochure I'll try to find thats for the 1989 Chevrolet Caprice. In the specifications it has a disclaimer stating that the engine may not be built by Chevrolet, but rather another GM brand. I'll try to find it and post it.

This angered a lot of people when they learned that their Chevy, Pontiac, Buick or Cadillac had an Oldsmobile engine. Soon after that GM Powertrain was established so they could use any engine in any brand. Also by incorporating all of the engine teams from all the brands, they could collaborate and put all their knowledge together.

Plus honestly, who wants to buy a Cadillac with an Oldsmobile engine? GM lost a lot of customer faith in those days.



Ironically the first offensive moment was fitting Chevy 350s in Oldsmobiles around 1976 or so. Back then the Olds snobs liked that "their" engines had more nickel in the block alloys and other things. But an Olds 350 was an entirely different animal from the Chevy one, with a different distributor location, bellhousing, etc. It was madness to have competing engine groups under one corporate roof.

In the late 80s caprice wagons were made in a different factory than their sedans, so sedans got 305s and wagons 307s. Canadians got some weird mixups too.
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