rich or lean? how do you know?

Hello,

Did you fail in idle or running test?

Well typical signs of running rich is high CO, however a lean condition will result in high HC.

I would look for intake air leaks by spraying carb cleaner around mating joints while the engine is idling. Any leak will change engine speed. Also you should make sure your temperature sender is good and the connections are clean.

Other things to check..

1. Fuel Filters
2. Fuel system pressure.
3. TPS

Ciao

Ed,

As blake says, if this was reflective of a fule mixture issue then this is most likely to be reflective in the CO reading.

A high HC reading is most likely to be a fuel burning issue, ie:- faulty plug fails to burn all of the mixture so some unburnt petrol goes out the exhaust which upsets the meter reading.

You may be looking at oil getting into the cylinders here, either valve stem oil seals or the start of a blow past the oil rings. I would suggest you go for a compression test as part of the diagnostic procedure.

Best of luck

Stuart

What is lacking here is info on what part of the test he failed. If it was during idle it could be a Lamda sensor.

Lacking Info and a crystal ball.

It is idle testing that fails. sorry not to include that. I put some stuff in the oil to "thicken" it a bit for the test only, but it didnt really help. DId a full filter/oil change. REplugged it, rewired plugs, new cap, new rotor, all of which helped, but still a few hundred too high on HC. I have not changed the O2 sensro just becuase I cant find one local that fits and OEM is a million dollars so I dont want to change that unless I have to.

Like I say, additives in the fuel sent it crazy. It idles very very rough with or without additives. Always has. I want to fix it, can fix it, and dammit I'm gonna..:) Our local temps here were hitting single F digits in the evenings when I can work on it, so I am trying to get a date extention til warmer weather can get here.

your thoughts gents?

I also want to add, I checked compression when I was changing the plugs. Seems pretty good still. 120's 130's 140's

also.....180k+ miles on her...

Hello Ed,

Stop using the additives, they dont fix anything.

This is what I would do. Because you are failing the Idle test and not the dyno test , and because your car has 188K on her I would ask myself "When was the O2 sensor changed". They are a 50k tune-up part. Then I would ask myself "My Jag is getting some miles on her, I wonder how that mechanical AFM is holding up?".

I am being very serious here. Many many driveabilty/emmision issues are from a failing AFM. They are spendy; 400-600$. But dont fret cause if you are mechanically inclined and can solder the AFM can be "reconditioned" for the cost of some silicone, wire, zip ties, and solder.

A good man has already made a nice website dedicated to AFM renewal so I dont need to go on here. Oh even though yours might say "Lucas", its still a Bosch design.

Cheers! Blake

Way cool. Me and a a meter are an unflouable combination, and if this is the culprit, I'm as good as fixed. I do have my factory manual (the green book) and I will also use the website. If its the AFM, then it shall be fixed. I'll at least give it a checkup.

Use a knife to cut the silicone that holds the black cover on the AFM, then with a heavy scraper I force off the cover slowly in one motion.

Look for groves in the substrate and move the contacts North or South as needed. As for measuring your temp sensor, I dont have that data, but it may be close to the Porsche specs.

HTH

DieInterim

noe of this makes sense yet until ia get it opena nd see what I'm dealing with. I know I tried a funky trick wiht the air filter once (leaving it out) and the car ran absoutely horrible. With this AFM deal, I can see why now.

Cover the tailpipe with your asshole and have someone switch the engine on. I find i can usually tell in this manner if the mix is right or not.

Regards AssBandit