Slow down light...can ignore if no cats?

Yup.

 

why?
no cats would ofcourse mean no damage to cats from raw fuel, however wouldn't you want to know why the light came on? i had some water from washing the car get into a sparkplug well short a coil and that tripped the light, sure i have no cats but it was a tipp off something was wrong. or am i missing something?

 

It is a non issue if you don't have the cats and disconnect the exhaust ECU module. If you leave it hooked up you may still get the warning light and after an extended time on, the engine management will turn off that bank of cylinders, while still pumping unburned fuel to that side of the engine. If you disconnect the ECU you won't have that issue. And you will still get the check engine lights if there is something else wrong.
BT

 

Car has no ck eng lights.

Car cannot generate enough exhaust heat to trip lights without cats. The only way they can come on is from a fault in the warning system.

 

You say that as though you currently have the cats on your car. This matters. You have to have the cats on for that signal to be accurate (or put another way, if you don't have the cats then that signal could only be a false alarm)

But...

Under the conditions where you have the cats on and are getting the SLOW DOWN warning, you want to take the light seriously (could lead to an engine fire or a half-power shut-down).

Now, if you remove the cats, sure that signal is going to go away...however, you could still have a fuel problem (i.e. the real cause of the original warning light in the first place).

So if you are thinking to yourself "hey, I've always wanted to remvoe my cats...and now I've got an excuse" then you may want to at least find the real problem, first.

Could be a fouled spark plug. Could be a bad spark plug wire. But something is causing too much raw fuel to get dumped into one of your cats...where it gets burned, creating way too much heat.

Remove the cats and you get rid of the heat and the warning light...but you're still stuck with dumping extra fuel (which means that you aren't running with full power).

 

Only after it has already turned itself to garbage and is in danger of setting fire to the car.


If the car has cats and there is any possibility they are overheating it indicates there is a real problem. Cats do not overheat on their own. They only react to a problem and those problems are a sure cause for lost performance even if it cannot be felt.

I have cats in my TR. It serves no purpose to remove them.

 

Well, real experts such as RifleDriver would know about the cats better than me.

Common wisdom or urban lore about Ferrari 348 cats is that they glow red in a dim light (if they are overheating). If that's really true then it might carry over to the TR as well.

Certainly a real fuel problem would overheat the cats and those cats could be checked with a laser heat gauge device (I bought one for $30).

 

I was thinking of daylight, you might see them glow in the dark but lets just say the problem can be serious enough that it should not be left to a judgement call.

My IR thermometer will not reliably measure temps in those ranges. What type do you have and how high does it go?

Mine goes south in the mid 500's F

 

Mine is from Performance Devices (Fchatter special) and now that I think about, it won't read high enough to be meaningful for a cat overheating.

 

Brian,
At what temperature reading will a bad cat be?
If you have twin cats, how close should their temps be?

 

Different generations of cats have different max temps. The metallic cats like F-40 360 and up are the highest. Most things I do from memory but I don't remember this stuff. I happened to have a 355 book out so it says

Operating temp 400-880C (750-1470F)
At 940 C (1720F) the light flashes
At 980C (1800F) it is on solid
At 1020C (1868F) Motronic shut down

At idle I see 450-600C normally and it is one of the parameters I use as a reference point for state of tune. It is a really good sign if they are the same.

All these are core temps. External temps are lower and vary a lot but around 500F at idle in the shop are common.


As a point of reference on our Bonneville car on gas making about 750 HP from 370 inches we like to see about 1600F at the exhaust port. We have seen 1800 but that is about when pistons and valves melt.

 

Interesting to see slight variations on the 512TR. Operating temp is listed as 400C-800C.

The slowdown will flash illuminate at 900C (+/- 20C)
The slowdown will stay illuminated at 940C (+/- 20C)
The Motronic will shut things down at 980C (+/- 20C)

Depending on the number of times 980C is exceeded, the motronic will shut things down for increasing lengths of time.


When the cat temperature reaches 1200C+, you'll be wishing you had a nice new Halon Ricambi fire extinguisher, or HyperFlow cats. Either way, you know where I stand on this issue



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Thanks Brian,
Would a converter that has gone out or has "lost" its internal matrix essentially function as a test pipe?

 

Yes but the internal shape sans matrix is not the best for flow.

 

Every generation got better. Judge4re should really be the guy to speak on this subject. It is something he knows a little about.

 

Thanks, Daniel.

 

Yes, but I will bore people to tears if I got into the details.

The slow down lights come on because something upstream is not working correctly. Catalysts are there to burn unburned hydrocarbons (along with CO and reduce NOx). If you are spraying raw gas on it, well duh, it is going to get hot. And yes, it can get hot enough to melt the ceramic support.

Again, the whole point of the lights is to warn you that something is not correct before you burn the car down.

Brian, out of curiosity, do you know what shape most of the aftermarket catalystic converters are? Round or ovals? I will get into the details on why I am asking with you off line if you want.

 

http://www.widebandcommander.com/productinfo.htm

 

The functional requirement is that you have to move both connectors from one ECU to the other (and then monitor if the abnormal behavior goes to the other dash light). If you've got enough wire length available, you don't have to swap the physical positions (but if you have swap the positions for wire length reasons just go ahead and do that too).

Having the light come "on" at weird times gets your attention, but you should also be watching the self-test very carefully at every restart -- not having the light come on for the restart test period is just as bad as having the light come on immediately when obviously cold.

 

To the best of my knowledge non direct replacement units are round.

Why?