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Help - '83 308 GTSI Can't pass emissions
Posts: 3From: PhoenixRegistered: Mar 2008
Junior Member

Saturday, May 31, 2008 7:54 PM

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My '83 308 GTSI defiantly failed Arizona emissions, twice in a row.

I just had the 30K rebuild done at 21K miles. The red one sitting as garage furniture the last 10 years in retrospect was a bad idea. All rubber and most aluminum items had to be replaced. We even replaced the valves and rebuilt the heads. People charging $700 for a USED water pump without blushing are committing a sin, but that's another story....

While we were at it, we pulled the remnants of a long grenaded smog pump, and pulled the heat shields off the headers, jet coated the headers, pulled off the restrictive catalytic converters and huge muffler "box" and added stainless steel glasspacks and tips opening up the exhaust so the car could breathe. And breathe it did....I was rewarded with a noticeable increase in power, the kind that pins you in the seat, especially at higher RPMs.

I didn't really expect to pass Arizona emissions without the restrictive cats, but tried anyway. It failed, with Hydrocarbon reading 20% higher than it should be.

I grudgingly crawled under the car last weekend and replaced all custom exhaust with the original stock exhaust, cats, big muffler box, and small tips choking off the end of the combustion process again. On the way to emissions, it was clear my performance edge had dipped a bit but it was worth it all if I passed emissions testing and got another 2 years before the next grueling exhaust musical chairs.

I was shocked the car failed emissions even worse with the stock stuff back in. I did my best to "light up the cats" by revving the engine just before my turn at the sniffers to no avail. In fact, the hydrocarbon reading was two times higher with the stock exhaust.

I inspected the Catalytic converters when I reinstalled them, and you could see the honeycomb pattern, nothing was rattling, etc. I assume the cats just did not light up sufficiently before or during the test.
Or perhaps, all the insulation and shielding we removed from the stock headers before jet coating served some heat containment purpose aiding more complete combustion.

One might argue a compelling case for the missing smog pump, but the car just passed emissions last time with broken smog pump 2 years before the recent 30K engine overhaul. At this point, with the old exhaust back in, the system is almost pre-30K tune except for the header mods.

Help...any ideas short of me moving out of this county (note - not country although I've considered it) with my stable of cars?


PS - An exhaust note observation - Not that the stock sound lacked pizazz since the 308 has a legendary sweet exhaust sound, but the new free-flowing catback delete custom stainless glasspack exhaust with tuned tips sound really lets people know this car is coming, including the kind of performance improvement you can feel in the seat of your pants. The higher db low RPM rumble is real gearhead music as well. The stock stuff is coming out as soon as emissions problem is resolved.

1983 Ferrari 308 GTSI

 Message edited by: PeteGruber on 06/01/2008 11:42:14

Posts: 153Registered: Feb 2004
Tom Manchester

Wednesday, June 04, 2008 7:20 PM

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My 328 flunked California emissions last summer after having passed by a whisker for the last ten years. I always replace the spark plugs and air filter, but this time it wasn't enough. The problem was that after twenty years, the catalytic converter was just plain worn out. The precious metal coatings are very thin, and after enough time and enough heat they delaminate and get blown out the back, leaving you with a beautiful ceramic honeycomb that doesn't do anything. Sounds like that's probably your problem. I bought a new Hyperflow CAT (about $800) and it passed with flying colors.

Obviously, anything that makes the car run rich will increase hydrocarbon output, but even if the car is running perfectly it won't pass without a good CAT. The caveat to that is that a new CAT will disguise a myriad of running problems, but if the car's not running right, the new CAT will deteriorate quickly. I guess if you're just going to take it off again that won't be an issue!



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