Hey folks.
After some maintenance work, I went back for smog retest.

Drove it for a good hour, as per advice here.

Passed CO easily.
HC - while reduced significantly from previous test - was still to high. Fail.

Any further advice?

Thx.

Also, my mechanic friend is trying to find a different air box to swap in for the test. Also, vacuum leak? Misfire? ( distributor cap? Spark plug wires?)

 

Shhhhhhhh.........
Don't tell anyone, but once I heard* of someone who put a little xylene (about a pint) in the almost empty tank to make an iffy car pass, and afterward fulled with highest octane to be found.
(';')





*information in this post is hear-say only and not intended to be taken seriously.

 

West Coast;


Me too, at lest two of us ! Misery loves company? Love is not the emotion going on here.


If the "air box" is the filter can, I thin k I have one. No snout, although.


My car is an LT1 lump. It is running just fine. But, it failed the "snap throttle test". In deed, on revving up and backing down, it belches black.


I got them to continue the test. All else is in compliance, but the smoke made it a fail. All the numbers in range .


Elinor:


What is 'xylene ?


My son counsels adding a bunch of Chevron's Techron and doing dome fast driving and then retest


I'll not go further as my thread heist has gone on far enough.


Carl ...

 

Pretty much Toluene, a dry cleaning fluid banned in Australia & NZ late 80's early 90's. It was widely used in the printing industry as a cleaning agent when I was a younger man.....now we use lesser chemical & more of good old fashioned elbow grease.

A bit like MEK, (methyl ethyl ketone) that was also banned in the 80's, We had all the good **** back then!, Jif & paint stripper just don't cut the mustard.

Nothing works like the chemicals we had back in the day.

 

what maintenance work was done prior to the smog test?

 

What I love about living in Queensland, Australia.
Get a Safety Certificate when you buy the vehicle(dodgy or not) and drive it as long as you like without another inspection!
Unless you get pinged by a roadside inspection (which I have had one in 29 years)
Downside is irresponsible owners drive around in dangerous buckets of ****.

I liked the old NZ "Warrant of Fitness" inspection every 6 months, they told you what needed attention before your next visit in 6 months time. It gave you time to get it sorted before the next visit.

 

High hydrocarbons typically means the vehicle is running lean, or experiencing a lean misfire.

Check for unmetered air entering the system. Oil dipstick seal, oil filler cap seal and bellows between airflow meter and inlet manifold are suspect areas for air leaks.

You and your Technician may find this article to be a good read:

Fuel injection and the Jaguar XJ6 4.2 Series 3 / AJ6 Engineering

 

I heard denatured alcohol is the stuff to use. Available at Home Depot and Wal-Mart. Car runs super clean on a 20% alcohol mixture. Just hearsay of course.

 

Home Depot sells it.
Or is it Lowe's.........
(';')

 

Elinor:


Thanks. I noted it. Our local ACE hardware has a well stocked paint dept.


Seems like a thinner for oil based paint.




NB:


Trying to get my head around black some from the tail pipes on CA's infamous "snap throttle" test and an HC measure that is right at maximum number on the two dyno runs. Marked as "Pass" on it an the others.


Black smoke has always meant rich rather than lean in my lexicon????


On my car, no smoke at idle, only the pleasant purr of a happy V8!


And lean would mean flaky running. Not here, goes like a good cat should.


If anyone thinks I should open a thread, rather than hijack this one, say so.


Carl,

 

My mechanic friend brought out his Jetronic kit. Tested all the readings we could on fuel rail, etc., And swapped in a better sensor on the exhaust right near the engine.

We're going to play with the timing chain - audible slap on startup ; want to "stop the bleeding" asap - and then focus on airflow meter?...or anything else you might suggest.

Did read and save the article that was linked.
Thanks to the poster of that.

 

On my '84 Ford F150 that failed the smog test in CA, it was the catalytic converter. Put on new one and drove back for the re-test and it passed with flying colors.

This article describes all the high HC failures: https://www.smogtips.com/failed-high...carbons-HC.cfm

 

Thanks for the link.

 

Roger:


Thanks for the link.


My lump passes the HC test on the dyno at the 15 and 25 mph tests. Same number!!!


But, flunked the snap throttle 'test'. Black smoke or particles from both pipes. Not a idle, only on revving up, then at revs OK!!!


Off to an old "idea'. Two 12 oz bottles of Chevron's Techron. One can to each tank. A bit of an over dose. One tank less than 1/4 and the other just under 1/2. Went on a freeway jaunt. D2 mostly and lots of throttle. Too much traffic for sustained runs.


Does it do any better? No one around to assist. And, I was not up to it yesterday. A touch of some bug...


Today. errands, I might get a look.


Carl
.

 

A misfire can cause high levels of HC emissions, either lean or rich.

It's been suggested that the OP replace the downstream catalyst to pass the California smog test and that may be the best alternative.

 

Thanks, I sure hope not.


As my car is a lump, it has one cat for each bank. The OBD I system.
Swapping out both ? My guess is Six hundred.


Running too rich? No lope at idle at all as a rich mix would do. No smoke a idle either.


Runs really nice. No lag on up throttle as a lean mix might do. Or irregular idle.


And, most confusing HC on the machine within limits, albeit just barely.


I've done almost all in town driving, with none at speed to clean it out.


Next.
1.Perhaps the techron and freeway run cleaned things up.
2.Remove the air cleaner and look again for "snap throttle" black smoke.
3. Get out my "smart" scanner and see if it detects any irregular #'s.
Not as sophisticated as an OBD II scanner, but indicative.
4. Pull the injectors and send to SD Faircloth for service. A Jag guy in FLA.


And/or leave it be for a time.


Carl

 

I hoped I got that one right.

 

You did.


But, probably much tamer than the real stuff, banned here as well, hence the "replacement".


Added to my musings on "next".



5. Slowly dribble in water with the engine at about 1500 to 2000 rpm.
Beware of a hydraulic lock.


6. Look again at NAPA, a local parts place, on the "snake oil" shelf for a "carbon remover".


7. Probably the same or similar to Elinor's suggested, "Sunnyside".





Carl