neilh

1984 Euro S, first time driven in over 2 years, just refreshed everything top side of engine, hold vacuum perfectly, no leaks , etc, etc.
Failed smog on high NO ( see attached).
I'm getting ready to hook up the LM-1 and CO tester, high NO with other readings in range suggests it is set to lean, anyone have an opinion.
Regards

Richard S

What cats are on it? And what shape are they in? How about the MAF? The Euro S uses a MAF with an adjustment screw, maybe that will have some effect. Also, does it have a Neutronics box (or similar) that splices in an O2 sensor to the LH?

Here are a couple threads on my own results:

High NO on an S4: https://rennlist.com/forums/928-foru...-solution.html

84 Euro S results: https://rennlist.com/forums/928-foru...-s-engine.html

Rich

neilh

Rich, Appears to have a new single cat, two in two out. Has a CA cert number on it and the tech says it was an 'approved' cat.
PO swapped out the MAF, so i have the new one in there, and the old one - if I need to try that. I'l probably try the adjustment anyway -
As you probably know in CA you can only get one 60 day temp operators permit now wh you fail, so i have to figure this out quickly (or not at all, as the car is being shipped out of state to SC in may, and they don't care!)
No O2 sensors, but i am installing a widebad sensor to use with the innovate LM-1 to see what is going on, both pipes into the cat have bungs in place already.

Neil

PRC928

Hi Neil,

Looking at the O2 column on the left, the numbers should be much lower, close to zero. This typically means the cats were not hot enough. I see this frequently at work. When we have a a reading like that, it gets a good "Italian Tune Up". Make sure to run the car failrly hard right before they start the test. The cats have got to be hot.
Worth a try.

Paul

Richard S

Neil,

Is the MAF on there now a regular S4 MAF? If so, it doesn't have an adjustment screw. I had an relatively new S4 MAF on the Euro S engine, and it didn't pass smog. I can't remember the results offhand, but I'll check for the print-out (it's a different test than the one I linked to). BTW, the results in the linked thread for the 84 Euro S are without an O2 sensor. It originally had a Neutronics box, but I've long since disconnected it. So your engine should pass without an O2 sensor.

Rich

neilh

No, its an earlier maf with the adjusting screw - correct part number per PET for a 84 Euro.

dr bob

Unfortunately, looking at the other (HC, CO) readings taken after the cat doesn't tell a whole lot about the actual combustion conditions. Connect the LM-1 and see what it says before you do a lot of tinkering with the mixture screw. Right now you have just the NOx as a possibly valid clue.

Bill51sdr

Neil, that engine is running very lean. The CO and NOX alone indicate this and the elevated HC may be due to a lean misfire. In any case, how old is the CAT? Excessively lean or rich conditions will ruin a CAT quickly.

BC

Drain the gas and put in a 1/4 tank of ethanol and see if that works. Worth a try. But don't let the ethanol sit in the tank more than a few days. That will make the car run lean, but it may lower the total temp, and the NO is not as high with ethanol anyway.

mickster

I thought in CA you can pre-test as often as you need and then take the actual test, no? A. Bauer in Oakland was going to do that to make sure a car during a PPI was going to pass smog (it was $45 for the test). I would do that after taking into account all of the suggestions below (except ethanol).

Michael

mickster

I wouldn't put Ethanol into ANY car unless it was Flex-Fuel certified or converted. That stuff will eat through any rubber-old or new. Why risk it for even 1/4 tank.

I hate that we have even 10% in our New York fuel pumps.

Just my 2 cents...

Michael

BC

I understand that you only have knowledge of what you have read in the press as they shout at the top of their lungs about any and all "controversy"

Ethanol will soften rubber - it does not "eat away" rubber. When ethanol is removed after a short time, the rubber will return to its original state. The tank is plastic. It too, will soften after an extended time with E85. I tested it - but it returned to its original state when I washed it out and put regular fuel back in. The time? 1 month. A FEW days, in the highly aged and well-carbon-coated tank, will do no harm.

Again. Ethanol is not some sort of monstrous, rubber-smoking corrosive material. Ethanol is alcohol - and if everyone here has had vodka, or any alcoholic drink, they have had ethanol.

For long term usage, when you use it permanently, you need aluminum to be anodized, the steel to be coated in some way, and the rubber replaced with viton, teflon, or some other flouro-material. The 15% gasoline acts as the proper amount of lubrication for the pumps and injectors.

neilh

Bill, Based on the appearance of the cat and the pipes around it - it is new and a custom fab job, - no discoloration around any part of it due to heat ( or the PO put in a X over that looks like a cat!). I'm off to DMV tomorrow morning to get a 60 day TOP, then i'll install the innovate wideband and LM-1 this weekend and see what is really going on. I'll run my IR temp gauge across it as well and see what the temp gradient is like - and stuff a CO tester up the pipe to see what that tells me as well.
i'll report back.

Rich9928p

All the Porsche 928 MAFs are the same part number from 1984 (euro) through 1995. The MAFs have a plug over the base CO adjustment screw. The 1987 and later 928s "ignore" the base CO adjustment, the lambda regulation manages air/fuel ratio.

GregBBRD

This is the same problem that almost all the "Euro S" engines have, in California, when they are performing properly. That is what makes them so difficult to own, here.

You didn't mention if this car has been modified to use an O2 sensor or not. Does it still have the original "Euro" brains?