Smog check HC question

Hello.

I replaced cat converter 2 yrs ago to bring down HC in wife's 81 VW Scirocco. Now the car's failing due to high HC again, with only about 2800 miles since last test! Results:

15mph, 1807rpm HC max: 162 - HC meas: 149 CO max: 1.09 - CO meas: 0.27 NO max: 1227 - NO meas: 983

25mph, 1938rpm HC max: 132 - HC meas: 172 FAIL CO max: 1.09 - CO meas: 0.27 NO max: 1227 - NO meas: 791

The car is driven every few days for short trips except was driven about

15-20 miles on the freeway before the test. Also, tester ran it for 2 minutes at 2K or so before starting the test. It has over 250K miles and does pass some oil - about 1qt every 200 miles or so I think. It doesn't smoke in normal driving though, and near-new plugs look toasty-good.

Question: I put a bottle of Techron in the tank. Is there a chance running that out on the freeway would clean up the test results, or is a new cat the answer? (Can a cat go bad in 2800 miles?!)

Also: what effect does Techron have on a smog test? Does it all have to be run out and refueled before testing?

thx, nf

Reply to
nutso fasst
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Have you replaced the O2 sensor? Or had someone tweak the mixture adjustment on the fuel distributor? (techron is a good idea tho, dirty injectors are another possibility) A VW shouldn't NEED a catcon to pass emissions, I know lots of people with gutted and/or known failed cats (myself included) who have passed smog tests with flying colors.

If you are anywhere near DC I advise you to just give the car to me, because early body Sciroccos are utterly worthless and certainly not any good for monster 1.8 turbo swaps :)

Seriously, though, a quart in 200 miles is not good, engine might just be getting tired if a real tune-up doesn't get it to pass. Your cat might well be dead already if all that oil is being burned and not leaking out. Good news is that vee-dub 4-cyls are near unbreakable so it should be ready for another good 250K after a rebuild.

nate

Reply to
Nate Nagel

The car invariably passed smog checks w/o cat replacement until 239K miles ('98). Then the HC numbers were way out, and a new cat brought them way down. The car passed in 2000 and just barely in 2002. In 2004 needed another cat to pass. So we get one cat going 238K, next 10K, and next...2.8K? I don't think it's been using THAT much more oil. It's been tuned, CO adjusted and O2 sensor replaced a while ago - symptoms don't indicate O2 sensor, do they?

Any idea what effect Techron will have on the test if tested with it still in the tank?

That sounds perfectly unreasonable. Hmm, maybe I should be asking what's involved in a 1.8 turbo swap! Anyway, I'm on the best coast.

Maybe so, but also needs a fender, weatherstrip, upholstery, headliner, paint, dashboard, wiring, CV joints...and who knows what else. It sure has been the best car I've ever had though. Only 2 sets of tires, 2 brake jobs,

2 timing belts, and IIRC only one clutch in 252K miles. In its youth it got 36 mpg hwy, 29 city.

nf

Reply to
nutso fasst

I just don't like your oil consumption... I would suggest just dropping in a junkyard engine (hell, I sold an '84 with similar mileage for $600 a while back that *didn't* burn oil) but I'm not 100% familiar with the earlier cars, I don't know what would and wouldn't bolt in without any mods at all. High oil consumption can cause failures of both the O2 sensor and the cat well before their time, and on a car with a cat you won't see any smoke until the cat is well and truly trashed.

nate

Reply to
N8N

Not really. Don't know how "clean" it burns compared to straight gasoline.

Basically lots of $$, and a wrecked car with a good 1.8T and transaxle. There's a kit available...

forgot to mention, might want to post to rec.autos.makers.vw.watercooled, or maybe VWVortex to get some more educated opinions.

nate

Reply to
N8N

Yeah, the oil consumption seems pretty high. The amount is an estimate, don't really track exactly when I add because I'm not the driver. I'm thinking I'll give this tank of Techron a long run today and see how quickly oil level goes down.

No $ to do major work right now but wife needs this car badly.

Any idea how Techron-treated gas will affect smog check?

Thanks for taking the time to reply.

nf

Reply to
nutso fasst

If you really want to keep the car,and keep it cheap, put in some Restore(?), engine rebuild in a can, put a few hundred miles on it, put in a new cat & get tested again. If you pass(you should), go home, remove cat, replace with old one, & drive it until next test. Repeat process as needed.

Reply to
Steve Walker

Brilliant! Thanks.

nf

Reply to
nutso fasst

The Techron is good, but you need more than that. With that level of oil consumption and all the short trips you have a lot of carbon build-up. Get a can of Berryman B12 Total Combustion Cleaner Kit. Get the engine well warmed up then follow the directions. Then go out and drive and FLOOR IT until smoke stops billowing out the tailpipe. Depending on how much buildup you have this will take a couple blocks to a couple of miles.

Run the techron in the gas tank too. After both of these change the oil, it will be black.

Reply to
E Frank Ball III

I doubt the Techron helped with this. What may let you pass emissions are using the hottest spark plugs allowed and changing the oil to

20W-50. Were 1981 Sciroccos part of a recall for high hydrocarbons? VWs made until some time in the early 1980s had valve stem seals that would wear out and cause a quart of oil to be burned every 100-200 miles. VW initially said this was normal, but they were later forced by the EPA to fix this, and a recall was issued that included new valve seals, valve adjustment, and, for some model years, elimination of the EGR valve and replacement of it with just an ignition vacuum advance time delay. I think the recall was called MK or KQ. The valve seals on this engine can be replaced without removing the head if you pump air into the spark plug hole or stuff non-fraying rope through the hole and turn the engine by hand slightly to compress it.
Reply to
do_not_spam_me

Exclusively Castrol 20W-50 since I bought the car w/10,000 miles on it.

Interesting...would a recall fix still be available if I never received a notification? I seem to recall, though, problems with Rabbits made in USA, not Sciroccos made in Germany. Anyway, the car passed all checks until 1998 (239,000 miles), when it failed HC miserably and got its CAT replaced for the first time. And I know it wasn't using a lot of oil when I was driving the car a lot prior to 1994.

Valve seal failure does seem a logical explanation for seeing smoke after the engine is started cold, and why it would use more oil per mile on short trips.

Good tip. Thanks!

nf

Reply to
nutso fasst

Berryman sounds like strong stuff.

I drove 200 miles today with Techroline in the tank, at speeds from

55-80mph, up and down some steep grades with about 3500ft elevation change. There was a noticeable improvement - a slight preignition rattle from 2500-3000 rpm is gone. The car is running better than it has in years. Even though half the trip was in 4th gear and I did a lot of hard acceleration, I still got near 32 mpg. On the downside, the engine used about a pint of oil.

I'm thinking of doing the smog retest without installing a new CAT, just to see if the Techroline really had a substantial effect.

Thanks for the suggestion!

nf

Reply to
nutso fasst

I had a Rabbit made in Germany, and it was part of the recall.

Reply to
do_not_spam_me

I found one recall (Audi, VW and...ISUZU?), unfortunately not for valve seals.

Make / Models : Model/Build Years: AUDI / 4000 1980-1981 AUDI / FOX 1976-1979 ISUZU / PICKUP TRUCK 1980 VOLKSWAGEN / CONVERTIBLE 1980-1982 VOLKSWAGEN / DASHER 1976-1980 VOLKSWAGEN / JETTA 1980-1982 VOLKSWAGEN / RABBIT 1977-1980 VOLKSWAGEN / SCIROCCO 1976-1982 Recall Number: 83V117000 Summary: THE FUEL PUMP MAY STOP FUNCTIONING WITHOUT WARNING. THIS CAN OCCUR BECAUSE AN ELECTRICAL CONNECTOR IN THE FUSE PANEL MAY OVERHEAT AND INTERRUPT THE ELECTRICAL CIRCUIT. Consequence: There is no summary currently available Remedy: DEALER WILL INSPECT THE FUSE BOX AND ITS CONNECTORS FOR CORROSION, AND CORRECT WHERE NECESSARY. A BYPASS ADAPTER TO THE FUEL PUMP ELECTRICAL CIRCUIT WILL BE INSTALLED. Notes: VEHICLE DESCRIPTION: PASSENGER VEHICLES EQUIPPED WITH FUEL INJECTION.SYSTEM: FUEL SYSTEM; ELECTRIC FUEL PUMP.CONSEQUENCES OF DEFECT: IF THE FUEL PUMP STOPS FUNCTIONING, THE ENGINE WILLSTALL OR FAIL TO START. A STALLED VEHICLE COULD CAUSE AN ACCIDENT ON THEHIGHWAY.

Reply to
nutso fasst

Oops, not so, it was Techron Concentrate Plus, not Techroline.

Reply to
nutso fasst

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