G.I.G.

....And on the M96/M97?

voiceprint1

how to tell if you have a worn injector(s)?

ADias

UOA would detect gas in the oil in significant amounts.

Carerra

@Flat6 Innovations Just using the @ to make sure Jake sees it.

Flat6 Innovations

We are closed for summer shutdown till 7.8
I’m at the beach.
I’ve yet to determine any sort of mileage or time in service point for these to be replaced. I need to have a ton more data when I make this recommendation, as it will be met with opposition.

I’d say watching for symptoms of rich running, and fuel trim is the best way to determine when injector replacement makes sense.

Carerra

I plugged in my Durametric and looked up the Bank 1 and Bank 2 fuel trim. It occurred to me that I have no idea what a good number is supposed to be.

I get about 22.3 mpg. I have sooty tailpipes (not really worse than any of my BMW's had as this is my first Porsche), but not clean. No real burst of oil on startup. The issue I have is I get codes for failing cats. As this first manifested itself when I hit a pothole and both cats failed simultaneously, I wrote it off as an electrical issue to come back to as I got more confident working on the car. Plus the Porsche Dealer wanted to start with $6,000 to replace the cats when I took it to them for diagnosis. (their diagnosis was to pull the codes and say $6k please)

My car is a 2010 Carrera S Rwd 6M Cab with ~145k Miles. The muffler bolts have corroded themselves to the cats. I have read many posts on how to fix this, but got it up on stands without the wheels and I did not had the ***** to go at my car with a torch and grinder when I needed to replace the plugs. (I had an indy replace the plugs and he did not need to remove the muffler) I have since had to do some forceful extraction to get my front brake discs off, so I may be building the confidence to try again.

At 10 years old, I could have a number of problems. I think the O2 sensors are most likely. However as a scientist by trade, I am trained not to ignore data that are inconvenient - as much as I would like to. Bore score also could generate these symptoms and I am trying to look holistically at the problem. I don't think it is cracked cats because, again they failed simultaneously, and the car runs like a scalded cat.

My actual question:
How do you specifically look for rich running?

• Low MPG?
• Specific values for trim on the Durametric?
• Cat temperatures?

Flat6 Innovations

Sorry, if you like actual data, and you are stuck on it alone, you will not like my answer.
The OBDII system gives a lot of data, but it can’t tell us all of what’s needed in most of the cases.

Put simply, if the engine acts rich, you must pay more attention to this than any hard data. So many things play into the data, that you can’t trust it alone.
The perfect fuel trim value is a “1.00”. Anything higher than this, and the system is adding fuel. Anything less than this means the engine is pulling fuel, which generally means that the O2 sensors show that the engine is rich, and therefore the ECU is pulling fuel. Now, exhaust leaks, and lazy O2 sensors can play into this, as well as different fuel characteristics.

So:
-If you have sooty tailpipes, clean them, and watch to see if they become sooty again
-Step behind the car at idle, and see if your eyes water, or if the engine smells rich. I can sniff out a rich engine from 2 car lengths behind it, as tuning engines has given me this sixth sense.
-Pull the spark plugs, and read them.

Fuel economy isn’t a great indicator, as driving style and where the car is being driven plays into it too much. You can have an engine running rich that does NOT get poor fuel economy. Essentially even 1 full point of air fuel ratio won’t impact fuel economy that much, even though it will impact engine efficiency a ton.

Determining if an engine is running rich takes more than something that plugs into a diagnostic port, in most cases. This is why modern “technicians” have their asses handed to them by these issues on a daily basis.

Iceter

If you had failing oxygen sensors, wouldn't you get a code for that specifically? Hell, my son's Avalon had a CEL and the scanner showed not only a code for a failed O2 sensor, but told me which one of the 4 sensors was malfunctioning.

Flat6 Innovations

No, not until they get out of range.
People rely on idiot lights, and codes too much. They believe that as long as some stupid light isn’t illuminated, there’s no reason to be concerned. In fact most engines that come here failed, are pulled from cars that have no CEL illuminated, and have no codes pending in the ECU.

If a sensor fails completely, or goes out of range, you will get a code, and that in most cases will trigger a CEL. This can tell you which sensor is the issue, but it has to get to a threshold first. While reaching the threshold the issue can be causing damage. Sensors and issues can take a while before they are severe enough to trigger the CEL, yet they are doing damage to the engine.

This is why we need to pay attention to the constants with he engine, have situational awareness and understand what’s normal, and note when something changes. Note how the engine runs, how it sounds, how it smells, and how it sounds. watch for changes in idle speeds, and vibrations at idle. Opening the door all the way, and touching the trailing edge of the door lightly with your finger tips at idle is a great way to note differences in the smooth running of the engine, aside from noting rough running indexes from the OBDII system.

Noticing how the engine sounds while its on the starter is another good one. Engines that have lower compression on some cylinders will show up here before anywhere else, if you have a trained ear, and have seen enough things blow up and wear out in your lifetime. No way to really teach anyone this stuff, it has to be experienced.

Charles Navarro

And injector wear is compounded by lack of lubricity in modern ethanol enriched fuels. The reduction of sulfur (which provided lubricity) and the addition of ethanol are effectively shortening the life of injectors. Like Jake said, keeping them clean isn't enough, you've got to address the lubricity issue.

carguy999

Bumping this thread - do fuel additives increase lubricity and clean? Or are those two separate things?

Charles Navarro

Typically gasoline fuel additives do not have any LE additives (lubrication enhancers). If you use a Top Tier fuel, they will have higher levels of LE that are a must for ethanol enriched fuels.

Fuel additives with PEA will clean the fuel system and address corrosion issues associated with ethanol enriched fuels.

swingwing

I use Shell V-Power or equivalent from Exxon and Texaco. I also use AMSOIL P.i. Performance Improver every 4k miles and AMSOIL Upper Cylinder Lube each tank. UCL tests superior to Lucas and Sea Foam. Here are product data pages:

P.i. https://www.amsoil.com/p/p-i-perform...-additive-api/

UCL https://www.amsoil.com/p/upper-cylinder-lubricant-ucl/