Jeff McConnell

I am fairly new to the forum.

I have a 1993 FD that is mostly stock. I have upgraded the radiator and AST only. I bought the car new in 1993 and had the engine replaced in 2007 at 120,000 miles. The car now has 134,000 miles with the original catalysts (both pre-cat and main).

I just failed my smog test by a couple of points. If the old limits were still in place, it would have passed. Here are the readings.

15 mph
HC 61 (max) 60 (measured)
CO 0.36 (max) 0.15 (measured)

25 mph
HC 37 (max) 38 (measured - FAIL)
CO 0.35 (max) 0.41 (measured - FAIL)

What do people recommend to get this to pass? I understand the pre-cat doesn't help much, but would a new cat make this pass? Does someone have "good" one laying around I could use to pass the test? After I pass, I am going to register the car in Imperial county (no Smog tests required).

HOZZMANRX7

iTrader: (43)

Get a new cat.
Yes.
No
Smart choice.

DO - a search for other options to help pass smog such as running alcohol or injector cleaner. Searching is good.
Don't - Double post

Jeff McConnell

Thanks for the reply.

Do you recommend a OEM cat or a after market version? The OEM versions are very expensive. Some of the information posted suggest the aftermarket version won't clean up the emmissions enough to pass. What are your thoughts?

magus2222

iTrader: (22)

i say change the plugs, change the oil, change the wires, and check the 02 sensor. you are failing just barely, i almost guarantee doing a tune up will do the trick

Lloyd

Jeff McConnell

I did change the oil before the test, but not the plugs or wires. The sensor is also original.

If I change these parts, does someone know someone who can check it before I get the "official" test?

I don't want to spend the money and still end up with a car I can't legally drive!

HOZZMANRX7

iTrader: (43)

Using non-dino oil will help. (it's combusting dino leftovers the sensor detects)

1/8 tank of gas with two bottles of fuel injector cleaner will help. (See above)

Hot, hot, hot cat before you roll onto the rollers helps (don't turn off the motor while waiting if possible)

Non-oem cat will get the job done, but won't last very long.

To get the most bang for your buck, I suggest you have the muffler shop unbolt the stock cat, install the aftermarket with separate flanges. Then after you've passed, unbolt the new cat and save for the next check 2 years from now. Bolt in the OEM cat for in the mean time.

Narfle

iTrader: (16)

you ought to pass fine if you get the car good and warm before you take the test. Cold cats don't test well.

Jeff McConnell

The car was at normal temperature when I tested it, but I had to wait about 10 minutes before they put it on the dyno.

I have always been scared of using fuel injector cleaners. They are designed to dissolve carbon deposits - the same thing the apex seals are made of. Or am I just crazy?

Natey

iTrader: (19)

02 sensor 1st and foremost. I'll bet it'll make the difference.
If that doesn't do the trick, a hi-flow like a Bonez cat is fine

magus2222

iTrader: (22)

trust me, using injector cleaner is totally ok, or you can always steam clean the engine, there a number of how-to's on this forum about how to do that safely.
and no, a high flow cat is not going to help, if anything it will make the readings go up. a high flow usually only has 1 brick of substrate, instead of the dual like a stock fd cat has, as well as a pre-cat, total you have 3 bricks of substrate.

try the de-carb, also, try a new o2 sensor, you should be golden. its failing under the lower load speed

Lloyd

Natey

iTrader: (19)

Thats weird. I didn't pass until i bought a Bonez and replaced my stock cat. Then I passed with no problems.
No precat, just the Bonez. My car also has a streeport from Karack.

magus2222

iTrader: (22)

your cats must have been totally shot then

Lloyd

Jeff McConnell

I think I will try the fuel injector cleaners with new plugs and oxygen sensor. Let hope for the best.

The O2 sensor is located on the pre-cat right? What is the best way to get to it?