CAL - 76 911S failed smog

[76-911s]

Hello,

I just got back from getting my car smog tested, and it failed CO at 15mph with 2.98, the max is 1.41. I bought this car from the Midwest, so it had no smog equipment. I bought a smog pump and hooked that up. I do not have the Thermo Reactors, hoping they would not notice.

The car passed everything but the CO levels at 15mph. I just did the cap, rotor, wires, plug, filters, oil, (pertronix ignition), so everything was new. The car was at temp, other than the 15 minutess i had to wait in line.

If i understand the failure, it's due to un-burnt fuel, causing a high reading

My questions are:

Should I put on the Reactors? ( i would have to buy them)

Would a MSD help burn cleaner? ( i would rather spend my money on this)

Is CIS out of adjustment, (too rich) If so, is their a tool I could by that would help while I adjust it?

Any suggestions would be most helpful.

Thanks,

Gary

[Joe Bob]

A good cat and a pre test with a tweak of the adjustment screw under the airbox.

[TT Oversteer]

Agree with the cat idea. Don't mess with the TR's. Someone right here on Pelican should have a good used SC exhaust you could get a deal on.............

[Joe Bob]

BTW, you need a 3mm allen key....a long one to do the adjustment.

DO NOT DO IT W/O having it hooked to an exhaust analyzer. You WILL hole a piston when it's too lean.

Depending on the State, you may be able to get away with just an adjustment. Prolly not CA. List your location in your profile....helps with smog advice.

[76-911s]

Thanks for the input.

What year(s) exhaust will work? Will I still need to adjust the CIS, or do you think the CAT will make the difference?

[Peter Zimmermann]

You say that you installed a smog pump on a car that didn't have one? OK, what parts did you put on, everything from the port injectors to the pump, or were the port injectors already there?

[Joe Bob]

Try the adjustment.

Lot's cheaper.....pulling an exhaust is a major undertaking. Snapped studs, busted knuckles, lot's of swear words.

[djdsc]

You didn't mention where your timing was set. Check your mixture and retard the timing to just below the minimum setting. Verify if this is with or without the vacuum connected at the distributor. This will help reduce the CO. Advance the timing back up after the test. Of course if you can run about 20% methanol it helps too.

There probably isn't a smog tech in the State that would recognize the TR's if they bit them in the a$$.

[76-911s]

I bought a smog pump, the "U" and the injectors into the heads, from a fellow Pelican. Was hoping to stay away from the TR's because I know what troubles they bring.

When I bought the car, I had the engine out and cleaned it and fixed all the "typical oil leaks" thanks to this site and its info!

I snapped a couple of studs already, that was a lot of fun. I put anti-seize on the studs and bolts, plus I had the exhaust off when i installed the smog a couple of days ago.

I agree, I would hate to buy an different exhaust, if there was an easier way. I guess my question still is, would an MSD and maybe a tweak of the CIS do it?

The timing is set at 5degrees with the vacuum line connected.

Anyone know what the going price is for a exhaust analyzer, or will I need to take it to a shop and pay them to make the adjustments?


Gary

[Joe Bob]

30-40 bucks for a pre test....bring the long allen key. You can buy a cheap Gunson tester, there were a few for sale recently in the classifieds.

[Peter Zimmermann]

The reason that I asked about the injectors is that if they were in place, without the pump hooked up, they can get carboned up to the point that they won't work properly. If you're sure that they're functioning properly...

Another system that you haven't mentioned is EGR. Is that there?

[76-911s]

Hello,

I cleaned the injectors and blew them clean before installing. There is no EGR system, and the tech said it was not required for the car.

I'm leaning toward seeing if i can do a pre-test and adjust, or purchase a Gunson tester.

Gary

[dhg1337]

I am right down the road from you. Monterey county does not use Dyno's. Soon I will be smogging my 77 930. It has passed in the past even though the smog pump was frozen and no belt. Prior owner may have had a smog connection??

I should be able to get my CO WNL by using a conversion table with my AFR gauge. I was looking at a smog check book a few days ago while getting another car done. No where did I see thermo reactors being required.The tech never mentioned them either. I got a new smog pump so it should pass easily.

I know with the older 911/930 you should take it to a smog place that knows Porsche's, then they can work their magic on adjusting the mixture screw. Average place with just fail you, such as the place you took it to.

I took a Boxster to the bad part of town to get it smogged one time, cheaper of course. The owner would not do it because he did not know where the engine was.

[Glen Pettigrew]

Gary,
A few options from my experience with smog test of other cars.

1. Take your neighbor in Salinas's offer to adjust Fuel Distributor with
his AFR guage.
2. afterwards put some "Guaranteed to pass" additive in you tank
and run the car hard for at least half an hour before a re-test.
3. If it still fails, bring it up to my place in Angels Camp and I will
hook it up to my old BAR 97 smog machine and try to adjust it to
pass the test at an official station. (I can't certify, not licensed and
the machine is too old.

Glen Pettigrew

[356911930]

I have a 1976 930, if I put in a dual plug system will make the car fail the smog visual?

[Quicksilver]

Originally Posted by 356911930

I have a 1976 930, if I put in a dual plug system will make the car fail the smog visual?

If the tech is sharp any change to anything that can change emissions will fail visual. I take my car to a station where they know nothing about Porsches and are unlikely to see one. That way they just hook it up and measure.

[TRE Cup]

Quicksilver is correct, and guess what that applies to installing a cat on a car that originally did not come with one !
76 and 77 911s had thermal reactors, egr system, and air pump . No oxy sensor, No catalytic converter. If you add the post 77 smog parts, the tech is supposed to see it and if following the rules, will fail you on visual. Logic has nothing to do with this , as they go by the book, not what the tail pipe can produce

So make sure the air pump system is 100%, check hc and co after leaning it out further (its a delicate balance with high mileage engines), get some alcohol to put in the tank (local auto parts stores sell this as "pass or don't pay" type of juice: It is actually alcohol that makes the car run cleaner), and make sure the car is good and hot when you go for the test.
The thermal reactors won't do much (almost all smog techs ignore these), as the air pump and a hot motor will help the most

worse comes to worse, I've heard of an aftermarket cat hidden in a stock looking muffler works too

[356911930]

Thanks Quicksilver/TRE Cup

I do not plan on putting the TR back on. I will install a air pump system and lean out the fuel mixturewhen I am ready to register. I have project car that needs a lot of work. Been sitting over 15 years...