Peter Zimmermann

I had a hunch that was the case...

BlackPearl

If the Motronic system is similar to my '87 944, there are 3 settings in the ECM for fuel ratios: Lean, Mid, and Rich.

Also, I agree with previous post that the O2 sensor and /or Cat. Conv. seem to be amiss? I'd definitely take it to a shop that has the rright tools and can really check it properly. You can test the O2 sensor with an ohm meter, but you have to know what you're doing, and it's a reach in the engine compartment.

One thing: for a couple more bucks (around $20 -$25) you can perform a pre-test on your car at most smog test locations. As a rule, I usually do this to make sure I'm in compliance, and/or I get a copy of the real numbers to analyze before making repairs/alterations to the system. And ... often, if the initial pre-test looks good and they run a certified test with passing numbers, they'll discount or waive the pre-test costs if they issue the certificate.

And: that Garanteed To Pass (GTP) can is mostly de-natured ethyl alcohol (DNA). Alcohol helps lower/slow the burning temp of gasoline (so does octane boost), and helps with higher NOX but not higher CO. If NOX is high and CO is low, pure alcohol helps improve NOX emissions. (Don't add more than 25% alcohol to your fuel ratio, or "issues" occur.) For high CO, you have to ffind a mechanical answer. If you add alcohol to your fuel, power goes down. After testing with DNA, go fill up with a full tank of 87 or 89 octane and run it through. Then, buy gas as normal.

That's been my experience, anyway.

Good luck, and keep it clean. ;-)

jakeflyer

How is the Air Quality in California lately? News said that there was a lot of smoke.You Porsche guys and SUVs messing up the California air are you?? Maybe tighter smog restrictions needed??

Peter Zimmermann

My SC is legal, and the sedan runs so clean that you could inhale from the tailpipe if you could figure out how to not burn your lips! The air, on the other hand, is so bad in Central, CA, that our particulate matter has reached unseen levels since they've been keeping records for that sort of thing. That's from the wildfires up north, of course. San Franciscans think, generally, that they're perfect, but that's only because all the smog that they generate travels east and then south, and we in places like Bakersfield get to breathe all their crap (the SF Bay Area was the last large urban part of CA to get enhanced smog testing, when they should have been second, maybe third). Add the particulates to that, and POW! We've had warnings for the last five days for healthy people to stay indoors as much as possible, sports events have been canceled, etc. People with asthma, and are in other ways compromised, are really having a tough time. YUCK! You would never know that our city is ringed by lovely mountains - you can't see them from the valley floor!

TT Oversteer

Brett, it's actually 1976 and newer cars that are subject to Ca smog testing. You can thank The Governator for the change from the 30 year rolling exemption. The dilemma for me was that the 75 and older cars are smog exempt but not zinc plated. I wanted a zinc plated rust free car which meant 1976 or newer and therefore smog testing. I spoke to a shop today and the guy told me the Motronic 3.2's usually run really, really clean and that it's almost certainly a shorted O2 sensor. I've already ordered a replacement along with the tune up parts I should have replaced earlier. Good idea about the pre-test. I'll consider that next time. This car had to go straight to the referee station due to its newer engine. I have to wait a couple of weeks for the next referee appointment then I will post results. Thanks for all your input!

BlackPearl

Good Luck!

Peter Zimmermann

Tough conversion - are you sure that all the correct electronics are there and functional - ECU, stock chip, etc., etc...

It is true that when the typical 3.2 has the CO set correctly, the rest just falls into place.

Lorenfb

"HC max allowable at 25 mph is 86 PPM. I tested 268. NO max 717, I tested 1435."

With a NOX level that high the possibilities are:

1. a bad/no CAT
2. a very lean CO setting (AFM adjustment, fuel pressure-bad fuel pressure regulator)
3. a "performance" chip ("pushed" timing)
4. a bad O2 sensor or not connected
5. a Euro DME ECM (no O2 system) with a non-functioning O2 sensor

TT Oversteer

Thanks for the great info Loren,

1) A stock cat is installed but has not been tested

2) I will have the CO setting set and fuel press. checked by a tech after the tune up and valve adjustment

3) I'll pull the chip and make sure it is stock (I have no reason to believe it's not)

4) O2 sensor is plugged in and contacts look good but the new sensor is on the way

5) How do I check to see if my DME ECM is US or Euro model?

Lorenfb

"How do I check to see if my DME ECM is US or Euro model?"

The most common USA versions have the Bosch part numbers of
0 261 200 050 and 0 261 200 082. The most common Euro version
is 0 261 200 051.

jakeflyer

I had a bad cat situation yesterday. There was a tail pipe rattle in the Miata (my son has the 911) and I took it to the muffler guy. He looked at the pipes and then hit the bottom of the cat and it sounded like marbles in a coffee can. Last time it barely passed smog by being under one # and exactly on another #. It now has more pep (yeah chuckle, snicker- pep squeek maybe) and I suspect the smog #s would be much better. I now have it in a Texas county that does not test for smog, but the new cat should inprove mpg.

r911

Yes, it really does sound like somebody monkeyed with your motor... that is a way high miss, and suggests it cannot be all stock.

"the SF Bay Area was the last large urban part of CA to get enhanced smog testing, when they should have been second, maybe third"
- Pete: very true comments on SFO. BTW, I used to work for the guy that forced the Bay Area to put in their air pollution plan. They would never have done it if they hadn't been sued. And the sprawl is just about as bad as in the LA area (despite the self-congratulatory sense of most in SFO -- most folks there tend to compare themselves to Paris anyway, not LA...)

TT Oversteer

Here's an update: After initially failing CA smog (miserably) I decided to do a full tune up and here's what I did:

Valve adjustment, new O2 sensor, distributor cap & rotor, plugs, air fuel and oil filters, oil change, and ran a can of G2P through the tank.

In addition, I took the car to a Porsche tech who put it on a gas analyzer to check out the mixture and emissions. He found a bad plug wire which I fixed. Gas analyzer showed all parameters below acceptable levels at idle and 2500 rpm (but not under load).

I felt confident that I did all I could do to correct whatever problem caused the initial smog test failure and went off for a retest.

Not only did the car fail the second time, it failed as miserably as before. Also the smog tech said there was "visible smoke" from the tailpipe which is an automatic failure regardless of emission values.

My conclusion: there must be oil getting past the valve guides. The car lets out a puff of smoke on start up after sitting for a few days and I will occasionally smell burning oil when coming to a stop sign. Other than that no visible smoke during driving and most start-ups. This engine is bone dry and I don't see a single drop of oil on the exhaust system. I've only driven 500 mi. since the oil change but oil consumption looks to be outside the 1000mi/qt limit.

So here's the elephant in the room: should I do a top overhaul? I assume the rings are ok as these generally last a long time. Guides, on the other hand, can be suspect on these engines. This engine allegedly only has 75K mi. but this is unverified. I've heard bad guides smoke on deceleration while bad rings smoke on acceleration. Any experience or advice on how to troubleshoot worn valve guides would be much appreciated. I don't want to jump to any expensive conclusions here but at the moment I have a nagging suspicion worn valve guides are causing these high hydrocarbon emission problems. I am comfortable with the R&R of the heads, cam timing, etc. so what is a reasonable cost for new guides and a regrind if I hand the heads to a shop? Thanks all...........sorry for the long post.

Oshin11

I just got my car smogged a few days ago....87 3.2 Carrera. Here are my numbers:

%CO2: 14.7
%O2: 0.1

HC (PPM): Max Allowed: 120 Average: 20 Measured (My Car): 10
CO%: Max Allowed: 1.00 Average: .10 Measured (My Car): 0.01

Staylo

Before comitting to a top end, I would suggest swapping the cat.
You mentioned that some performance might be missing.....a plugged cat will do that.