Hello all,
I am a new member from Melbourne Australia driving a P340 2019 F Type Coupe. As soon as the warranty expired I started to explore customising the car.
From previous experience with high performance cars I have always replaced the ceramic cats (with higher flowing metal cats) due to risk of cat failure and ceramic particle ingestion.
With the aggressive fuelling and tuning of the car, and evidently other F Type owners experiencing cat break down, I thought it was a good idea to get motorsport 200 Cell Cats.
I fitted these myself and can say that they sound just fine and certainly increase exhaust volume and performance. With an active exhaust, it is no issue quietening the car when needed.
So all happy there.
Issue I have encountered is with carbon build up on Bank 1 sensor 3 Ho2S (heated oxygen sensor - rear of the cat) which when I removed it, appears to be heavily covered in carbon build up. When I removed the sensor to fit the cats, it was completely clean.
I am aware that O2 sensors can go bad on these cars but my car has little over 20,000 kms and I know the state of the O2 sensors prior to a custom tune. I am exploring tuning questions with my tuner but my question to forum members is,
has anyone noticed the degree of carbon build up of their O2 sensors? Is it normal to have this much carbon? I know its a very niche question, if anyone has experience, please let me know. I am ordering a replacement sensor but want to avoid recurring issues.

Bank 1 sensor 3 HO2S totally covered in carbon buildup

 

What did VAP say?

Posting here first will get you a bunch of opinions, none of which will necessarily help as most owners don't do actual real work on their cars, or fully understand the inner workings of the engine and ECU. You "could" have a sticky injector adding too much fuel. You "could" read that no one here has this problem, suggesting that it's likely only your car. Posting here first "could" also be viewed as a passive aggressive jab at VAP, by not giving them a chance to answer your question more quickly.

 

Thanks for your reply kb58 - my first response on this forum and somewhat a surprising one.
I am literally asking if other owners experience carbon build up as pictured on any of their HO2S - is this normal?
No other subtext , jab at VAP or passive aggression.
I do not think it's unreasonable to seek information from multiple sources to form a view.

 

When I replaced the most downstream O2 sensor on my car with a VAP tune I seem to remember the tip was a dark tan color.

Here is something I found online that might help:




Unfortunately I can't find a photo of a good one but it seem light tan or tan is good and sooty means rich or burning oil. FWIW

 

Thanks for that.
Useful diagnosis info there.

 

That's an awful lot of soot on the sensor. If the sensor on the other bank dos not show the same I doubt it's related to the tune. Unless, that is, your "custom tune" is different for the two cylinder banks :/

Loading up the sensor on one bank can be an indication of fuel or spark problems. What led you to pull the sensor? Did you get a CEL/MIL? Did you check for codes? I would expect that there would be a misfire code on one or more cylinders. The first thing I'd be looking at is injector problems but again, there should be malfunction codes to give better information than the speculation of some forum member half a world away.

 

I would check out the pre-cat 02 and see what it looks like. A lot of new exhaust systems and hfc's have factory coatings and other things that burn off over the first few days. It could be something like that or it could be an overly rich condition, in which case the upstream 02 would look just the same. If it's clean, it's not the tune.

 

Good point Doc.
I have put the car on my lift and am going to check out the other sensors too.
So far I can see the HO2S that threw the error is faulty as the heater circuit is open circuit.
Not sure if the rich condition is a subsequent fuelling response to the bad sensor - my current theory.
For this reason, I am doing my checks and not defaulting to blaming the tune.
New sensors on their way. Will check the live data to see where the AFRs and EGT go.

 

hi lizzardo
Yes, I got a CEL and scanned the code P0042-00. This points to a bad heater circuit in the O2 sensor.
Did a resistance check across the terminals of the sensor and confirms its open circuit.
So replacing the sensor first and going to see if the sensor gets soot coated again.
Either the AFR is running too rich and killing the HO2S or the HO2S went bad and caused rich fuelling - is what I am exploring first.
So simple stuff first, replace the sensor.

 

Hate to be a bummer but downstream 02's are not there for measuring afr, they're strictly to monitor converter function and would not cause a rich condition.

Here is something else to consider. It may be the fact that the heater element failed in the sensor that has caused it to soot up. I can't say that for sure but coincidentally I just installed a heated o2 in my 6th Gen Camaro SS for my air/fuel gauge. The manual states not to install the sensor in the exhaust until it's been wired up because running it unheated can cause it to foul prematurely. Make of that what you will🙂

What are you logging with? Hp tuners?

 

Thanks for the insights.
I have removed the other sensors and they are also covered in carbon, indicating rich fuelling (as far as I can tell).
The other sensors are not faulty and pass the heater circuit resistance test. So I do not think its a sensor specific issue (aligns with what you're saying too).
When I get the new sensors, I will replace all 4.
Live data via my Autel can give me some O2 sensor readings but will have to see my tuner to look at the tune.
One of my cars is a Holden SS (Zeta platform, so same as the Camaro up to 2015).
So simple to work on in contrast (Supercharged 6.0 with Meth Injection / cammed/ ported heads ).
Good for low 11s on the qrtr mile and its a wagon !

 

​​​​That's awesome. Bet people at the track have no idea what's coming. So that has the ls3 then? Good platform and you're right, so easy to work on. My nephew has a 15 which we have tuned and done headers on, but nothing like your Holden. I used to have a GTO 15 years ago that I absolutely loved. I think that was called the Monaro down by you. Fun cars.

Sounds like you're on the right path....keep us updated. I've got a pulley and tune on the way myself...

 

The Aussie and the Brit make a good pair.
Engine in the Holden is an LS variant L77- although cylinder deactivation was removed in the first 6mths from new.
They have weak lifters. The mods started there :-)
Don’t mind creating and working on resolving issues with my cars.
Get to meet great people and suppliers in the industry.
it’s all part of the ownership experience that I , and I am sure many others in this forum, seek.
Enjoy pulley and tune upgrade - awesome VAP mods.

 

Quick answer to the question I originally posed, Yes, this level of carbon build up is not uncommon and is not necessarily a function of tuning rich fuel mixture.
Remediated by replacing the sensor that had a failed heater circuit - not uncommon.
Are O2 sensor failures uncommon in the F Type ? The extended warranty offered in the Nth American market suggests failures are common.
For those outside warranty, I have listed the Bosch part numbers in another post (Bosch make the OEM parts).
So cost of remediation isn't as painful as Jag OEM.