Cat Problem???

Is there a simple way to check for a cat being obstructed?

Do thay evere break down and cause a Slow down light??

 

Well if you put some corn in its diet you can see how long it takes to come out the other end.

 

fatbillybob your reply is an inspiration.
Sometimes I wonder why more people don't more people don't seek and reply with helpful advice and solutions on this thread and other times people make it quite obvious why not.

 

Yes. Temperature measurement upstream and downstream of each with laser thermometer.

Stirring the litterbox, are you?

 

George -

the slowdown light is triggered (when everything is working) by an overheating of a cat, which is measured by a thermoprobe which is threaded into the catalytic converter between the O2 sensors. The thermoprobe runs to a small box the size of a 1/2 pack of cigarettes called a Cat ECU. The Cat ECU looks like this:

http://www.ricambiamerica.com/product_info.php?products_id=208023

If you see the slowdown lamp illuminate you could have one, or several of the following conditions:

1) An overheated cat! Either caused by bad timing, disintegrating catalytic core, cracked exhaust manifold, etc. etc. An overheating cat is serious and can burn the car down. To be fair, "failure" of those things is just the outward symptom of upstream conditions. Keep that in mind. Ferrari's idea to shut down fuel delivery on the side of the car with an overheating cat (i.e. the Slow Down mechanism) is well-intentioned.

2) A broken thermocouple. Maybe a frayed wire, who knows.

3) A broken cat ECU. It happens. Early ones had lousy sealant on the backside, and when they get hot (normal engine compartment environment) the sealant cracks around the body of the cat ECU and allows moisture to enter. Voila! Moisture + Ferrari electronics = problems. In this case, either replace the cat ECU with a new one (new ones have green sealant which is supposedly longer lasting than the ones with black sealant), *OR* attempt to dry it out and silicone over the cracks.

This might sound silly coming from a parts seller -- but don't just throw parts at the problem. Its expensive and hasty. Have the situation properly diagnosed. So you can fix it once and get back to driving.

 

I appriciate the response I will get a lazer thermometer and see what the verdict is..

Some one has to stir the pot lol

 

So far I think the problem lies in the cat itself? The engine when the cat is cool (before the slow down light) runs perfect.
Is there a way of telling if it is obstructed by breakdown or just have to remove it to be sure...

Thinking of switching cats to see if problem moves to the other side of the engine. I think that would be the definitive proof with out fancy shop equipment. Of course I will not be able to drive it that way because of the differnce in the cats position but it may prove the problem.. Any other advice is appriciated.

Thanks again Jack

 

You can use an IR thermometer and measure its temperature, or pull the CAT and see if it is clogged.

 

Switch the probes around, a lot less work.

If you remove the muffler, you should be able to tell if a cat element has failed.

 

Sorry George...I could not resist. There are some good suggestions so far and look at this thread I started for the future of SDECU's we are working on. It will give a few more clues to how the system works and how to debug it.

 

I understand ..thanks for posting again.. I appriciate the link and ill look at that thread..

I am just frustrated I think and maybe a bit thinned skinned over the problem..

 

You forgot one thing gentlemen. You may also check the Air system to the exhaust. If you are not getting air and just fuel, you will overheat the cats. Check valves have a way of blocking air when they are rusted internally. Go with the thermometer before tearing into anything. More time spent diagnosing before condemming parts is a lot cheaper.

 

checked my generic sd2 after my problem earlier all the following codes were present:
P1165
P1196
P0305
P0306
P0307
P0308
P1198 hot cat
P0436 ?? no idea

I went for a short ride and returned and checked the sd2 no codes. I did not go far enough to get the cat really hot but figured if it were an engine problem the codes would show before the cat got hot??

I am really leaning toward a bad cat.

 

Not me. Cats respond as a symptom of a problem rarely a cause. While you are not throwing codes if the IR thermometer shows a nice temp difference upstream vs. down stream of the cat you can bet there is some positive function. Poor function would be seen in new error code between the upstream and down stream 02 sensor readings that he ECU looks for. All the codes you got except the last 2, which I do not know what they are, are bank 2 issues. The misfire codes in 5-8 especially point to an ignition failure. Dumpping uncombusted fuel due to 5-8 missfire upstream of will burn the gas in the cats throwing the SDECU light as a hot cat...a symptom. That's my reasoning anyway. I would see if the codes return and if you get the bank 2 misfires again I'd be looking at the wiring there, plugs, injectors, fuel pressures to start. A plugged cat give more of a symptom of idling great then no power when you take off or acelerate. Watch "beverly hills cop" the "banana in the tailpipe scene". Plugs also do not fix themselves hot to cold but electrical problems often do.

 

Often you can hear rattling inside if you put a dowel, stethescope, or something against that and against you ear.

 

I think the cat wants to be let OUT!

 

I will check both input and output temp tomorrow as well as checking sd2 codes again...

Stating to lean toward Bob diagnosis...

I wish there was a way of telling which came first the chicken or the egg...Is a damaged cat causing restriction causing engine misfire codes or are engine misfires causing the cat to get hot...

Anybody have a cut away view of the cats??

 

Yup this is usually the symptom before final "banana in the tailpipe" effect.

 

Here is a thought that doesn't cost any money....take the cats out and look at them, I don't know, just a thought???

 

What? Do something! Why? when there's the silver bullet approach. Shame the health industry hasn't come up with this concept, we'd never have to go to the doctor, just go on a forum for the diagnosis, then search around for the cheapest source of drug or something maybe close. Then we'd become the 'expert' for the next guy.............

 

If you cannot see ANY light thru them when pointed directly at the sun on a clear day, like mine ... CHUCK um.




Or hollow them out and straight pipe um ........

 

Man, that made me laugh!!!!!

 

Now this is funny...and spot on. Particularly the sentence..."Then we'd become the 'expert' for the next guy..." Bravo...and ain't that the truth. Then you have the yahoos that want to bring their own parts for you to install. I ask "do you bring your own food for the chefs to cook at your favorite restaurants...? I thought not!

 

Tap the cat lightly with the palm of your hand or a plastic hammer (when it is cold). If it rattles, it is probably broken up into pieces. You can remove the 02 sensor and look inside the cat with a small video camera (most shops have them now, only a couple hundred dollars) to see if it is broken.

 

Good idea Brian. Glad you're still on here. I'm sending you a PM.