Suzuki Forums banner

1 - 20 of 20 Posts

·
Registered
Joined
·
15 Posts
Discussion Starter #1
my 87/carb wont pass emmissions. the report says that the carbons are double what they should be. un-burned fuel maybe?

anyhow, could it be a sensor or maybe my carb. it passed last year no problem, but has sat for a while until recently when i started driving it. it runs great, so i have no idea where to begin.

any ideas?
 

·
Registered
Joined
·
1,230 Posts
high CO (carbonmonoxide) or high HC (hydrocarbons)???

CO levels are elevated by partial burn of the fuel usually from a too rich condition. Faulty O2 sensor or dirty air filter will cause this, having your timing off can also cause a partial burn.

HC levels are elevated by unburnt fuel dumping into your exhaust. Usually caused by a too lean condition or misfiring ignition. Fouled plugs, faulty wires-cap-rotor-coil can cause this as well as vacuum leaks.

The common factor with both of these is the catalytic converter. The purpose of the CAT is to oxidize CO into CO2 and to oxidize HC into CO2 and H20. A malfunctioning CAT will cause either or both of these levels to be elevated depending on the efficiency and condition of your engine. The one time my samurai failed smog it was from a bad Catalytic Converter.
 

·
Registered
Joined
·
15 Posts
Discussion Starter #4
i need to look at the print out again, but i am pretty sure it was both CO and HC. where's the best deal on a new cat converter?
 

·
Registered
Joined
·
1,230 Posts
rockauto.com has them for 45 bucks... I think someone posted a discount code here for them a couple weeks ago.

heres a discount code they sent me for 5% off. good till 8-30-2010
19288351621797
Enter the code above in the "How did you hear about us" line of the shopping cart
 

·
Registered
Joined
·
33 Posts
Cats are one of those things where you get what you pay for. I tried a cheap one and it had very little cat in it which still caused it to fail. I bought a nice one from magnaflow and it worked like a charm. Also note that you must break in a new cat with a couple hundred miles.....they can fail if you test right after installation. Also get it hot before testing
 

·
Registered
Joined
·
32 Posts
Cats are also sized for the engine displacement.

You CAN put too small a Cat on, though I am not sure if too big a Cat is a problem.

I just had a new exhaust installed (head-pipe back to the tailpipe, complete), and the Cat is a tiny little thing. It's almost "cute."

But then the engine is a tiny little thing as well.

Bob
 

·
Registered
Joined
·
32 Posts
To be honest (if you were asking me), I have no idea. The shop gave me a decent price, and I didn't discuss brands, and I don't see any stamped on the components. The Cat's only about 10" long, and the oval muffler is maybe 12" long.

The idle is silent, though you can hear some exhaust note at 1500 and up. The slight back pressure actually seemed to improve performance at normal RPM (3000 and lower).

Being 2300 miles from home, I just did what I needed to to get the Sammy ready for its trip home and didn't ask too many questions. Normally I am pretty hands-on, but after doing the eng, the bumper fabrication (for flat towing) and the engine rebuild, I just handed over the $210 (parts and labor end to end) and took my chances.
 

·
Registered
Joined
·
328 Posts
I had a Magnaflow Calilifornia cat installed and it passed California emissions. Passed by a mile for CO and HC, but passed Ok for NOx, well above average, but still passing. I figure that may have something to do with the lack of back-pressure and the fact that the EGR valve uses back-pressure to meter EGR flow.(not as much EGR flow with less back-pressure)

With a freshly rebuilt engine and carb, with the Magnaflow cat, my numbers were, at 15 and 25 mph(1,992 and 2,419 RPM);
HC 0 10 PPM Max 146 126
CO .00 .01 % Max 1.00 1.22
NOx 806 712 PPM Max 1096 956

My muffler is a Thrush 2" turbo muffler. It is quiet at idle but gets a bit noisy off-idle. I never find it too loud inside, but I can tell when passing buildings that it is fairly loud, off-idle.
 

·
Registered
Joined
·
1,230 Posts
you bring up a point worth mentioning about california (and I believe all other CARB standard states, but not positive) In 2009 any Pre-OBD2 vehicles (95 and older) are required to have a CARB certified cat with the certification number stamped on the cat. A lot of the cats you can buy online say things like non-california or not legal in california. Those places usually wont even ship one to a california address. If you currently have an older cat that isn't stamped, that was installed pre-'09 it's still legal, but any cat installed after Jan, '09 must have the cert stamped in it.
 

·
Registered
Joined
·
15 Posts
Discussion Starter #12
i found a magnaflow cat converter that i think i will get. i am also thinking that i need to replace the o2 sensor and the pcv valve. hopefully the EGR is ok and i wont be out too much money for the other stuff. the truck passed emmissions with no problem last time it was tested, but it sat for a long time until recently. hopefully this isn't going to be a big deal.
 

·
Registered
Joined
·
32 Posts
I guess we should just be grateful we own Sammys that are cheap. A friend in Redding, CA just had to replace both cats on their BMW 540i. The cats were $1700 each, plus $500 installation, or a grand total of over $4300 w/ tax.
 

·
Registered
Joined
·
33 Posts
I just had my 88 inspected with a new Magnaflow CAT...here are the results:

Low speed (15mph)
HC Standard=297 / Mine=5
CO Standard=2.69 / Mine=.02
CO2 Mine=14.8
NOX Standard=2115 / Mine=561
Dilution Standard=>6 / Mine=14.8


HIGH speed (25mph)
HC Standard=290 / Mine=4
CO Standard=3.66 / Mine=.02
CO2 Mine=14.8
NOX Standard=1943 / Mine=473
Dilution Standard=>6 / Mine=14.8

I do not know how many miles are one the engine but I know it has not been rebuilt in recent years.
 

·
Registered
Joined
·
328 Posts
I just had my 88 inspected with a new Magnaflow CAT...here are the results:

Low speed (15mph)
HC Standard=297 / Mine=5
CO Standard=2.69 / Mine=.02
CO2 Mine=14.8
NOX Standard=2115 / Mine=561
Dilution Standard=>6 / Mine=14.8


HIGH speed (25mph)
HC Standard=290 / Mine=4
CO Standard=3.66 / Mine=.02
CO2 Mine=14.8
NOX Standard=1943 / Mine=473
Dilution Standard=>6 / Mine=14.8
Oh I wish California had those loose tolerances! I had an '88 Festiva with an original 250k cat(basically no cat) on it that would just squeak by Houston emissions, but would have been a "gross polluter" here...

Even with a new cat here, my first pass, with the timing set at 17*(7* too much) my Samurai would have garnered gross polluter status if I had not requested a pretest, which does not count.
 

·
Registered
Joined
·
33 Posts
Sorry...I do not have a model number...I got it installed from a local muffler shop. It is a universal weld on one. The guy said it is a high end one that he has had alot of success with. I paid $200 all-in.
 

·
Registered
Joined
·
328 Posts
MagnaFlow cat Part Numbers for Samurai;
49 state emissions
Direct Fit 22617 $119 Summit Racing and others
Weld-On 91004 $64 Amazon and others

50 state emissions(California legal);
Direct Fit 39617 (Does not seem to be available yet)
Weld-On 39004 $145 Amazon and others(This is what I have)

Personally, if I did not have to deal with California emissions, I would go with the direct fit cat and do it myself.

I planned on going that way anyway and taking my chances since my Samurai was in Nevada when I bought it, but the direct-fits were back-ordered. I wound up with the weld-on cat hanging lower and rearward from where it is supposed to be, but did not have time to hang around in Las Vegas and have them fix it. I'm suprised I did not get dinged for that at inspection time...
 
1 - 20 of 20 Posts
Top