Catalytic Converter?

EestiSpider · Post by **EestiSpider** » Wed Sep 19, 2012 12:48 am

So after trying nearly everything to get my spider through inspection I have decided that I probably need a new catalytic converter. If anyone know of any cheap ones for a fiat let me know.

Sincerly, Toomas

P.S.

I was looking at a magnaflow cat that was pretty cheap. Is this my best bet?

1981 Fiat Spider 2000
1985 Mercedes Benz 300sd turbo diesel

So Cal Mark · Post by **So Cal Mark** » Wed Sep 19, 2012 1:15 am

what are the emission readings? What state are you in?

bradartigue · Post by **bradartigue** » Wed Sep 19, 2012 7:32 am

EestiSpider wrote:So after trying nearly everything to get my spider through inspection I have decided that I probably need a new catalytic converter. If anyone know of any cheap ones for a fiat let me know.

Sincerly, Toomas

P.S.

I was looking at a magnaflow cat that was pretty cheap. Is this my best bet?

1981 Fiat Spider 2000
1985 Mercedes Benz 300sd turbo diesel

Your best bet is a converter from a vendor that fits, about $220 last time I bought one (yesterday). The Magnaflow one is well known to be a poor fit.

EestiSpider · Post by **EestiSpider** » Wed Sep 19, 2012 12:33 pm

So Cal Mark wrote:what are the emission readings? What state are you in?

I'm in Delaware and the emissions that are failing are the CO and HO.

EestiSpider · Post by **EestiSpider** » Wed Sep 19, 2012 1:32 pm

So Cal Mark wrote:what are the emission readings? What state are you in?

So Cal Mark,

Double checked and it the HC (PPM) which is reading out at 375 and is supposed be at a low limit of 220. The CO(%) is supposed to be around 1.20, but low is 5.58 and the High is 7.52.

majicwrench · Post by **majicwrench** » Wed Sep 19, 2012 2:08 pm

I haven't done stuff with a gas analizer for almost 20years, but methinks you need to make it run right before changing convertor. HC in unburned fuel and there is way too much of it.
Hopefully someone with more modern skills will chime in.
Keith

bradartigue · Post by **bradartigue** » Wed Sep 19, 2012 5:05 pm

majicwrench wrote:I haven't done stuff with a gas analizer for almost 20years, but methinks you need to make it run right before changing convertor. HC in unburned fuel and there is way too much of it.
Hopefully someone with more modern skills will chime in.
Keith

I would agree, you can make a FIAT hit those numbers without a catalyst so long as you have a progressive downdraft and tune it correctly (e.g. all the stock carbs and the 34ADFA). Extremely clean burning cars - but you usually have to have a catalyst to pass visual.

Tune it up right, then get the cat. In the interim you can use your old one; if it is clogged then knock the guts out.

So Cal Mark · Post by **So Cal Mark** » Wed Sep 19, 2012 10:42 pm

it's WAY too rich. Replacing the catalyst won't bring those numbers down enough to pass. Make sure the air pump is pumping air and that the air injection railed isn't clogged. Then repair the carb and jet it properly. If you replace the cat with those CO numbers, it won't last very long

steve8462 · Post by **steve8462** » Thu Sep 20, 2012 12:57 pm

i have a related question, i am struggling with the tuning of my carb on my 1979 spider. all the emissions have been stripped (PO) an i have recently relieved my converter of its precious metals (wink-wink)

i need to know if the carb has to be leaned out to compensate for all of this. the PO had installed what looks like a factory replacement rebuilt carb on it. he wasnt mechanically inclined so i have to assume that he either A. tossed it on w/o tuning it, or B. tried to tune it by randomly turning the adjustment screws to try to get it smooth.

i would like to take the carb to ground zero and start fresh, making the proper adjustments to get it as close to perfect as i can. i have noticed that if i give the tailpipe a prostate exam my finger comes out with a black soot on it. what does this indicate?

bradartigue · Post by **bradartigue** » Thu Sep 20, 2012 8:28 pm

steve8462 wrote:i have a related question, i am struggling with the tuning of my carb on my 1979 spider. all the emissions have been stripped (PO) an i have recently relieved my converter of its precious metals (wink-wink)

i need to know if the carb has to be leaned out to compensate for all of this. the PO had installed what looks like a factory replacement rebuilt carb on it. he wasnt mechanically inclined so i have to assume that he either A. tossed it on w/o tuning it, or B. tried to tune it by randomly turning the adjustment screws to try to get it smooth.

i would like to take the carb to ground zero and start fresh, making the proper adjustments to get it as close to perfect as i can. i have noticed that if i give the tailpipe a prostate exam my finger comes out with a black soot on it. what does this indicate?

You may be running rich. Tune the thing, it isn't difficult, and if set to factory settings it is probably not right to begin with. Start by setting the ignition timing then tune the carb, then fine tune both.

majicwrench · Post by **majicwrench** » Thu Sep 20, 2012 10:02 pm

Finger up the tailpipe is not a valid test of anything. Modern fuel always leaves tailpipe black. How does car run??
Keith

steve8462 · Post by **steve8462** » Fri Sep 21, 2012 8:29 am

majicwrench wrote:Finger up the tailpipe is not a valid test of anything. Modern fuel always leaves tailpipe black. How does car run??
Keith

the car appears to run well. i just don't want to run it too lean and burn the valve nor do i want to run it to rich and cake up the valves or waste fuel. i was told to screw the mixture screw in till it seats, then back it out a turn and a half and use that as my starting point. where on the tach should the idle be once warmed up. and also, do i make all these adjustments cold or once warmed up?

majicwrench · Post by **majicwrench** » Fri Sep 21, 2012 10:34 am

SHould do idle mix warm. Warm idle should be around 800rpm, give or take. A turn and 1/2 is about right, look for the best idle as you turn it a bit in and out. If you have to go too far off that turn and 1/2 something else is amiss.
YOu are not going to burn a valve from too lean.
Keith

steve8462 · Post by **steve8462** » Fri Sep 21, 2012 11:46 am

majicwrench wrote:SHould do idle mix warm. Warm idle should be around 800rpm, give or take. A turn and 1/2 is about right, look for the best idle as you turn it a bit in and out. If you have to go too far off that turn and 1/2 something else is amiss.
YOu are not going to burn a valve from too lean.
Keith

thanks for the info. you seem yo know your stuff when it comes to carbs. - odd question, once the car is up to temp and i'm driving it, the carb seems to be slow to returning to an idle once i take my foot off the gas. it doesn't do it when its cold. does this sound like a carb problem or an accelerator cable issue. i have checked the routing and the cable doesn't seem pinched, worn, or bent at such an angle as to create a bind. any ideas? (carb looks new, a factory rebuild style, but new. i think the box it came in was actually in the trunk when i got it. but my OCD wife cleaned it out and threw it away before it dawned on me that i might need it)

tartan18 · Post by **tartan18** » Fri Sep 21, 2012 12:46 pm

Adding an inexpensive throttle return spring from AutoZone cured my idle issue (not returning to 850 rpm).

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