Catalyst below threshold fix

Ken, as you know this fits with what I experienced. I refused to believe that the hyperflows I installed were the issue. But nothing else ever worked. Ferrari of Washington sniffed mine with the hyperflows in and declared it one of the best tuned 355s they had seen. I traded the car with the CEL on and the next buyer bought it knowing about the problem. In hindsight, the only thing we did not try was swapping the cats back to the godawful stockers. I have a pair of good factory cats in my attic, just in case.

 

1996+ OBD2 cars *are* going to flash a trouble code if the exhaust is too dirty post-cat. Ditto for flashing a code if the exhaust post-cat is too consistent (even if "Clean" while being consistent). Might have to use O2 emulators to make good high-flow cats work on some cars.

 

Well I ended up destroying a Hyperflow cat. Troy said that there was something wrong with my engine etc and not the Hyperflows.

I checked everything from timing, fuel injectors, MAF, comprression, leak down and many other things.

Put the stock ones back in and no more issues since so don't know what happened here but much better with the stock cats in.

The Hyperflows are now a museum piece on my shelf!!

 

I've owned my F355 for 7 years. I bought the car with a tubi exhaust and stock cats and a CEL bulb that was removed. When I brought it into service Ferrari of Seattle they said there is a problem with the SD-2 and went looking for the bulb and replaced it and said the CATS were shot with only 8,000 miles on the car. After two engine out services where the valves were misstimed by another dealer and a set of Hyperflows were burned up, I took the car with a new set of hyperflows to the dealer in Seattle after the manifolds had burned through and they concluded the car was miss timed and set that straight with a 3rd engine out at 24K 4 years later still producing CELs after they fixed the timing and it started to burn through a second set of Hyperflow which Troy gave me at cost. I had also purchased a factory set used and had them re-cored. Frustrated Ferrari of Seattle in concert with Italy concluded the exhaust system with the hyperflows and the Tubi were way over area and offered to put the car back to original OEM using my re-cored Cats and the factory muffler they had. When my tin ear wife got in the car - she said it sounded like ****. That did it because she was right! I agreed to run the car for a year sounding like **** (factory) to see if it got any CELs - none. I'm an aerodynamicist by training and I was on a quest to get the Tubi sound back. My current configuration has re-cored stock CATS with a choke washer at the aft end of the CATs dumping into the Tubi which I reinstalled. This achieved the proper exhaust area match and eliminated the stumbling and burbling which was occuring at decel and idle which I believe is at the root of the CELs. I have driven the car a year with No CELs. The car sounds like **** at idle just like the OEM muffler but when the bypass opens up in the tunnels I get that wonderful Tubi sound. Just before I die, I'm going for one last spin in the tunnels with the Tubi muffler and the Hyperflow CATs just for the sound of it and I'll leave a note for the kids what to do if they ever want to put out the CEL that is bound to occur when they have the car!

 

Well, I have had 2 engine out jobs and am still going. It may seem that you need to stick to factory settings. If they have invested so much money in the development of their cars then they must know what they are talking about.

Learning the hard way!!!

 

Here's the link for the L-shaped O2 sensor adapters from Weapon R. Looks like a novel solution to delay the O2 sensor reading the CO/CO2 content between the front and rear O2 sensor. Inexpensive, too! Might be worth a try.

LINK: http://translate.google.com/translate?hl=en&sl=ar&u=http://www.weapon-r.com/&sa=X&oi=translate&resnum=1&ct=result&prev=/search%3Fq%3DWeapon%2BR%26hl%3Den

 

George, the difference here is that both Ken's car and mine were timed exactly right, engines in tune, cats working. Initially, I was worried the CEL was on because the engine was mistimed, and I sent it to FOW to have that looked at. Everything else was perfect. No issues running aftermarket exhaust with stock cats, and I don't have any stumbling at decel or idle. Your problem sounds like it was a deeper issue.

We simply had CELs on perfectly tuned engines running hyperflows that were working properly. There seems to be something about the ECU in the 5.2 cars that does not like the hyperflow cats, at least in some cars.

 

But the problem is that my timing was checked out on the second engine out and it was spot on. New spark plugs, new plug leads, and everything you can imagine so what gives ???

 

Something is being missed.

I have installed a great many of the HyperFlow Cats on everything from a 94 to the 99's and have never had an issue. I have delt with untold numbers of very hard to find Motronic gremlins over the years but all were resolveable. It might take strapping an SD into the car and driving it while checking all the parameters to see what changes and when.... but something is wrong.

If you are burning them up, the fuel isnt being controlled properly, simple as that. If the Hyperflows burn up but the stock ceramic cores dont....they are glowing red and I personally would rather have the cats shed a core than have a pair of fireball's bolted in place.

If a cat works at idle its going to work even better at speed as it gets hotter unless the fuel control is altered in some way. It is just this type of problem that led me to working with the gold plated connectors for the Motronic to put an end to the poor connection issues for good. Hugh F355 will be doing the final 'owner install test' this week and helping write a procedure and then it will be available on FerrariAds for those that want to try it. It is always possible there is a sensor or component failure you are dealing with but the chances are far greater it is a simple connection issue causing all of these problems and now there is a tried and proven solution for that. A full season of testing on a couple of "problem cars where everything was perfect" showed that wasnt quite the case and there was room for improvement as these cars have remained trouble free since the install. Dont blame the HyperFlows just yet.

Dave

 

I make no endorsement, but here's a more direct link to that same O2 delay: http://weapon-r.com/english/index.php?main_page=product_info&products_id=6219

 

I should point out that once my car had its 3rd engine out it was also timed perfectly in a task force approach between Ferrari of Seattle's top mechantic and the factory. There was an A- B comparison with a 97 with about 8000 miles with stock CATs and Stock Muffler which ran stabily and mine was unstable, with the Tubi muffler and stock CATS that had been recored. When we put the stock muffler on it stablized exactly like the other 97. All the dynamic measurements from the cats were recorded on a laptop while driving as well as in their shop. I am reasonably convinced the problem is over area exhaust, because when I put the choke washers in up stream of the tubi I had it retested by Mark at Ferrari of Seattle and the parameters of CATs were very close to the factory OEM and the car runs stably.

 

Thanks ND. I copied the link directly to that page, but for some reason it did not come out that way when I pasted it into my post.

 

The F355 engine valve overlap and the other dynamics of a very small flywheel and variations is exhaust area - not to mention the electrical dynamics of how the O2 system influences fuel injection during decel transients and idle there is no wonder in my mind why there isn't a large variation in outcomes. I believe my car may be 2 sigma from the mean and the only way Ferrari could satisfy the US emission and noise regs and maintain stable operation is to throttle the exhause so cars like mine fell in the acceptable band of operability

 

Has anyone ever tried one of these? Seems like a good idea if it were to work.


Darrell.

 

For the 355 cat/O2 CEL, I'd think that you'd want to buy 2 of those O2 delay tubes, and then have a competent machinist or welding shop cut/weld a dialable valve into to it so that you could go from 100% open down to 1% open so that you could see if changing the O2's ability to sniff in quantity would stop the CEL.

Because if closing off some portion of that delay tube doesn't solve the CEL...then your 355 CEL problem resides somewhere else...away from the cats/O2s.

 

If it is an exhaust problem how can one explain that 90+% of the cars have no issues with this combination of muffler and Cat? What ECU number (three number code) are you running on your car? Dismount the ECU and look at the tabs...has the cover been removed in the past?

 

Dave thanks for your interest, During the investigation they swapped the two latest mod standards for the ECU. They told me I had the latest mod standard according to them but I can't remember what mod that was - I think it was a Mod 4. They have been very careful with the connector tabs as they know that's a sometimes an issue. They even swapped the ECU from the 8K car which was their benchmark, with no change in the irradic result before they put the OEM muffler on.

 

Here ya' go. You'll see I'm taking good care of the interior : )
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Look at the Motronic ECU and tell me the three digit code on the label or snap a photo of it.

Sometimes it is the smallest little things that cause the biggest headaches! About 1/3 of the way through the terminal replacement test, 'Hugh F355' has uncovered 4 problem areas I believe very well might resolve all of his issues. Each one by itself is fairly benign but when combined can add up to a problem and it takes a very focused effort to find these minuet issues.

I am not suggesting any wrong doing in any way, I just believe there is a logical explination for what you are experiancing as I deal with issues like this every day and if you look hard enough the answers are there.

 

Wow! What an interesting thread. I was told but never bothered to confirm Ferrari is voiding warantees 360 and newer for tubis and aftermarket wheels. It makes sense. As the precision of traction control like emission control gets better and better each part of the car is designed to work as a "system." Its like your seatbelts work best with your airbag but not as well apart. NoDoubt is onto something but not for the reason of solving the problem but to turn the CEL light out. Ricers have been doing the "staging" of the second O2 sensor bung since the first days of OBD2 because they often upset the designed balance. They are also often running no cats so they are either running sims or "bung stagers" to trick the ECU. Aeroman's comment about being 2 sigma out is very accurate because 1 sigma is getting smaller and smaller as the equipment and engineers are able to target a smaller and smaller spot on the target. The 355 may go down in Ferrari history as the most complicated or misunderstood Ferrari ever built or the one with the smallest sigma.

As to Dave's comment about connections and ECU's once it took me a year to find the electrical problem that messed up my car's ability to start properly but yet run perfectly. The solution was simple but the diagnosis was the bit**! Those Ferrari electrical problems will kill you. I do not know which is worse...trying to fix'em or doing the brute force manual rewiring of the whole bowl of pasta.

 

Due you recall what the recuring P code was?