'88 Cadillac smog (Emission test) fails

[spasm3]

Originally Posted By: eljefino


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.

Remember when 77 trans am owners learned they had the olds 403 as the 6.6 engine, not the pontiac 400.

 

[marc1]

Originally Posted By: eljefino

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.

1975 Pontiac Ventura with a factory installed Buick 350 was the first offensive moment for me. Owner came into my speed shop to buy headers for it and I had assumed he transplanted the Buick into the engine compartment. Beginning of the end for GM.

 

[jhellwig]

Originally Posted By: mehullica
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?


It sound like fresh gas and a long drive would get the cat burnt out and possibly working better. A new o2 sensor might help also.

 

[FCD]

Give it an italian tune-up, new plugs , lean out the mixture if it's a carbed engine, here all cars regardless of age pass an emissions test, unless you have a classic car registration, which is very expensive so i don't

 

[Ducked]

Originally Posted By: momo
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.



Anyone know what's in it?

I've heard of people using ethanol, methanol, and acetone doping of the fuel to lower emissions, but havn't tried any of them.

 

[sciphi]

As others have said, change the oil immediately before the test. As in, the morning of the test or night before. Get the car good and hot before. A tuneup likely would help matters, too.

 

[DoubleWasp]

The biggest enemy you have is the GM "can of pellets" catalytic converter under the floor. That thing was well known to become worthless for cleaning the exhaust in no time. The wash gets beat off the pellets as time goes on.

Really restrictive design as well. Honeycomb cats are far more efficient.

When I had to get my 1992 Caprice to pass emissions, I put the converter from a late model F-Body under the floor. That thing must scrub pretty good, because I was told they'd never seen an early 90's GM test that well.

 

[Jarlaxle]

Originally Posted By: Tegger
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?


All Olds 307s had Quadrajet carbs...which is another issue: it is an electronic carb. Another possibility is a bad oxygen sensor. (At this point, I'd replace it as a precaution.)

 

[Jarlaxle]

Originally Posted By: stower17
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 had one in a Custom Cruiser wagon...passed emissions (the IM-240 roller test!) without a problem. They ran in G-bodies to 1988, Cadillac Fleetwoods and B-body station wagons (including Caprices) to 1990. (They were GM's last carbuerated light-duty vehicles.)

 

[artificialist]

You have to have good spark plugs, wires, and a distributor cap, but the following items may be needed.

If your car is from the 80s and uses a carb, I am sure there are dozens of vacuum hoses that need to be replaced. No matter how careful you are in removing hoses, some plastic parts attached to them are going to break.

PCV valve should be replaced, a failed PCV valve will make the engine function like it has a vacuum leak.

Oxygen sensors should be replaced because they react too slowly when they get old. Before OBDII, there wasn't an error code for a sensor that was responding slowly. The only error codes were for excessively rich constantly, excessively lean constantly, open circuit, and short circuit. Back in the 1980s, Nissan and VW had a "Sensor" light that would illuminate after a certain number of miles. That was there to tell the driver to get a new oxygen sensor.

Locate every coolant temperature sensor and replace with OEM. If a coolant temperature sensor reports too low of a temperature, the ECU will not go into closed loop mode and that will lead to a higher HC level.

I hope the carb doesn't need to be rebuilt. My dad's 1987 Hyundai Excel had an O2 feedback carb, and it cost him a lot of money when it failed.

 

[momo]

For those who are wondering about other numbers from the emission test, here it is

 

[momo]

I think before I do any replacement for sensors or any major repair, I will use either seafoam treatment (or guarantee to pass) in the gas tank and drive the car for 1 hr before the test, then go the test while the cat is hot

 

[spasm3]

Originally Posted By: momo
I think before I do any replacement for sensors or any major repair, I will use either seafoam treatment (or guarantee to pass) in the gas tank and drive the car for 1 hr before the test, then go the test while the cat is hot


Did you read what we posted you?

Get the old fuel out, its turned to kerosene. Run a bit of fresh fuel through it, and b-12 cleaner. forget the seafoam, it has oil in it which will not burn as clean as the e-30 i suggested. The E-30 fuel has more alcohol and has less carbon so the hydrocarbons will be lower.

Again with high HC numbers at speed and idle, the ignition has to be looked at, plugs wires and if applicable cap and rotor.

 

[spasm3]

Btw your cat is working fine, thats not the problem, but if you keep the HC numbers high, it won't continue to work and you will need a new one.

 

[artificialist]

The high HC but low CO may mean that all you need is new spark plugs, spark plug wires, a distributor cap, and a distributor rotor. I am still going to recommend that you get a new oxygen sensor due to age, and due to the fact that one wire O2 sensors usually don't cost much.

 

[momo]

Originally Posted By: spasm3
Originally Posted By: momo
I think before I do any replacement for sensors or any major repair, I will use either seafoam treatment (or guarantee to pass) in the gas tank and drive the car for 1 hr before the test, then go the test while the cat is hot


Did you read what we posted you?

Get the old fuel out, its turned to kerosene. Run a bit of fresh fuel through it, and b-12 cleaner. forget the seafoam, it has oil in it which will not burn as clean as the e-30 i suggested. The E-30 fuel has more alcohol and has less carbon so the hydrocarbons will be lower.

Again with high HC numbers at speed and idle, the ignition has to be looked at, plugs wires and if applicable cap and rotor.


Thank you and other people who advice me.

I am not familiar with E-30, from where I get it and does it harm the engine if stay too long?

 

[momo]

Originally Posted By: artificialist
The high HC but low CO may mean that all you need is new spark plugs, spark plug wires, a distributor cap, and a distributor rotor. I am still going to recommend that you get a new oxygen sensor due to age, and due to the fact that one wire O2 sensors usually don't cost much.


To be honest with you, I don't want to go that route since I am not planning to keep the car for long and I just need to pass emission, so I may sell the car this summer

 

[spasm3]

Originally Posted By: momo
Originally Posted By: artificialist
The high HC but low CO may mean that all you need is new spark plugs, spark plug wires, a distributor cap, and a distributor rotor. I am still going to recommend that you get a new oxygen sensor due to age, and due to the fact that one wire O2 sensors usually don't cost much.


To be honest with you, I don't want to go that route since I am not planning to keep the car for long and I just need to pass emission, so I may sell the car this summer


The $8 can of seafoam is 1/2 of what a sparkwire set for that car would be.

If you are not careful , you will spend more trying to pass on the cheap than just doing it inexpensively right.

 

[momo]

Originally Posted By: spasm3
Originally Posted By: momo
Originally Posted By: artificialist
The high HC but low CO may mean that all you need is new spark plugs, spark plug wires, a distributor cap, and a distributor rotor. I am still going to recommend that you get a new oxygen sensor due to age, and due to the fact that one wire O2 sensors usually don't cost much.


To be honest with you, I don't want to go that route since I am not planning to keep the car for long and I just need to pass emission, so I may sell the car this summer


The $8 can of seafoam is 1/2 of what a sparkwire set for that car would be.

If you are not careful , you will spend more trying to pass on the cheap than just doing it inexpensively right.


Thanks for your quick response.

 

[Bladecutter]

Originally Posted By: momo
For those who are wondering about other numbers from the emission test, here it is

The fact that your low speed and high speed HC numbers are nearly identical means that you have a problem with a part on your car, causing the ignition process to not be completed fully.

Since it's happening at idle speed and at 2500 rpms, I'm going to rule out carbon deposits causing pre-ignition or egr clogging.

You're looking at weak ignition caused by either an ignition coil going weak, or a spark plug not fully igniting the mixture in one or more combustion chambers due to a bad spark plug, spark plug wire, or a burned contact in the distributor cap.

If it were my car, a completely fresh set of ignition components would be step 1, including the ignition coil.

Since you're not me, and are a cheapskate, you can do something else, in stages:

For you, step 1 should be drive the car, get it good and hot, and go to the test facility while good and hot.

Step 2 - If that doesn't work, drive the car until all the current fuel is gone, then add in several gallons of brand new fuel. Go back, retest the car, and see if you pass.

Step 3 - If those two tried fail, next step if to buy a bottle of fuel system cleaner, like Techron Complete Fuel System Cleaner, add it to the tank, and a few gallons of gas, drive the car until all of it has been burned, then add a few more gallons, and go retest to see if you now pass.

Step 4 - Post what your emissions score is at this point. If it looks exact the same as this one you already posted, then you now know you HAVE to inspect your car to see what parts need to be replaced. Start by pulling the spark plugs. Is one fouled? If yes, since you are so bloody cheap, swap it with the one in the next cylinder. This way you can then determine if the problem stays with that cylinder (spark plug wire, distributor cap, cylinder related issue, etc), or if the problem follows the spark plug (guess what you need to replace if this happens). If you get the car running better, go retest.

But you need to remember, you're cheap. How much does it cost you to keep retesting the vehicle if you fail it every time? How much more is the car worth if it passes the test? How much will gas cost if you keep having to buy more of it to keep driving around and retesting the car, and getting new parts, or running cleaners through the fuel system?

Ultimately, if you can't afford to fix the car, you shouldn't even have bought it in the first place. I learned this lesson back in the late 90's when I bought a 1982 Monte Carlo with the 229 Chevy V-6. I couldn't get that car to pass Colorado's emissions tests at the time, and I was throwing parts at it, and they were not having the needed effect. I wound up junking the car, and losing all the money I had put into that pile of crud over a year long period of my life, when I needed every one of those dollars I spent.

BC.