| Author | Message | ||
| tony hopkins (Tonyh)
New member Username: Tonyh Post Number: 45 Registered: 12-2002 |
Rob, in answer to your question, the coolant gauge was showing v. high readings prior to the tubi going on and on one occasion in London traffic, it actually dipped into the red line.the car was serviced at the same time as exhaust was swapped and there was found to be a problem with a fuse on the r.h. rad. fan which was replaced.the car has been running fine since. Tony | ||
| Michael N. (Man90tr)
Member Username: Man90tr Post Number: 796 Registered: 4-2001 |
Bill and Rob, You both said it properly - I said it wrong. I said richer, but the explanation properly stated was exactly what Bill said -- excess unburnt fuel now gets burnt in the pipe and gives the different sound as if it is running richer. Excuse my layman's terms, but I should have said excess unburned fuel, not richer as in getting more fuel. Now that I think back the mechanic said - "smells like its running richer". he also said that depending on temp, at idle it might have a "popping" sound because of the fuel being burnt in the pipes. I definitely have that. But you all are correct - still idles at 1000 rpms without moving, so the idle is not rough, just the sound and feel is different. Thanks. Michael PS: All 1984 - 1995 TR's are injected. | ||
| Bill Sebestyen (Bill308)
Member Username: Bill308 Post Number: 527 Registered: 5-2001 |
Michael N, I'm not sure removal of the cats on a fuel injected car will make it run richer. Isn't your TR injected? On a carb car, removal of the cats probably will cause it to run a little richer because of less back pressure in the exhaust system. An oxygen sensor in the exhaust stream on an injected car presumably would sense any change in mixture but the ecu should compensate and restore a proper mixture. Another thing that may be happening is that removal of the cat system will allow some additional unburnt fuel to escape through the tail pipe. This may be perceived as running richer but in fact is running the same as with the cats fitted. This excess fuel would normally be burned in the cats but now is just expelled, resulting in a noxious odor. | ||
| Rob Schermerhorn (Rexrcr)
Member Username: Rexrcr Post Number: 796 Registered: 11-2002 |
How do you know it's richer? This makes no sense. The catalyst is there to scrub the exhaust of environment damaging compounds. The catalyst does not determine air/fuel ratio. Ed, if you brought the car to me and stated the facts of catalyst overheat, I'd do a proper diagnosis beginning with physically verifying wire and plug connector integrity, then a exhaust gas analyzer test pre-catalyst. If a misfire or miss-adjusted fuel distributor was found, adjust/ repair accordingly. Tony, by running cooler do you mean that when you open the engine cover, less heat radiates into your face, or is the coolant temperature gauge reading lower than before, or what? I suspect it's the perception of temperature reduction in that the catalysts do operate at a much higher temperature than a straight pipe will. This elevated temperature in the engine compartment costs little or no power (sometimes the intake temperature sensor is fooled into a lean condition, but this is usually noted while the car is not moving). Removing a properly functioning catalyst and damaging the environment does not make your car run better. Modern catalysts cost about 4 hp, not worth the harm to the air we all breathe. Yes, catalysts for Ferrari's are expensive, but they are for Honda's too. I had an ignition trigger malfunction 10 years ago on an out-of-warrantee Civic which resulted in a catalyst melt-down. Cost of new OEM catalyst: $700 on a car that was $8000 when new. Peace  | ||
| Ed P. (Ebp)
Junior Member Username: Ebp Post Number: 206 Registered: 12-2002 |
Barney, Call my cellphone. I'll be a moving target this morning... | ||
| Ed P. (Ebp)
Junior Member Username: Ebp Post Number: 205 Registered: 12-2002 |
Russ, Thanks again for the interesting input. I'm going to meet my mechanic in about an hour. I hope he has a magic wand. | ||
| Michael N. (Man90tr)
Member Username: Man90tr Post Number: 794 Registered: 4-2001 |
Bill S., Thanks for the specifics on the temp readings on the cats.. I have a question. I was told that once I replaced the cats with the test pipes that the car will run richer and that did occur. With the test pipes it runs a bit richer at idle and as a result it is a slightly bit less smooth at idle. More of a race car feel and like sound at idle, not the sometimes eery smoothness when it had cats. What is the reason for this richness without the cats? Michael | ||
| Russ Turner (Snj5)
Member Username: Snj5 Post Number: 461 Registered: 2-2003 |
OK - this is getting really interesting. Since you have shown you have spark to both sides (yea!) with increase gas smell, what are some of the things that can cause an overrich condition that would cause loss of power (too much gas) and pass extra gas into the exhaust to overheat? 1. Open injector spraying too much fuel into one cylinder 2. Stuck open cold start valve 3. malfunctioning frequency valve (little injector looking doofer by your fuel distributor that modifies the control pressure which controls richness). 4. A bad nonfiring one plug or plug extender. #1 and #4 are single cylinder specific - could try looking at all of the plugs and comparing - is one or more different? #2 & #3 are across all cylinders, so all of the plugs would look rich. So, my next diagnostic test would be to look at all the plugs. Does this make sense? Can't wait to hear what the difficulty is, and hope to learn something. Good luck! best rt | ||
| Barney Guzzo (Trinacria)
Member Username: Trinacria Post Number: 434 Registered: 8-2002 |
Ed I'll call you in the morning. Damn, what happened? I've been away from my computer that last few days. | ||
| Ed P. (Ebp)
Junior Member Username: Ebp Post Number: 203 Registered: 12-2002 |
This is all great information. Here is some more "data" on my specific situation: Disconnecting one coil at a time doesn't seem to make much difference. It still runs on alternate sides, but doesn't seem any different with both connected. Maybe I smelled a little more fuel in the exhaust. There is plenty of exhaust coming out the tailpipes, although the passenger's side pipes have more. This doesn't change with the coil test either. The engine definately feels weak and bogs down when I give it gas. I wonder if I'm going to drive my mechanic nuts tomorrow with all my "new knowledge"... Don't worry guys, I'm not going to give up my day job.. | ||
| Bill Sebestyen (Bill308)
Member Username: Bill308 Post Number: 526 Registered: 5-2001 |
I just want to add a little info here. The sensor sticking into the cat is a thermocouple. They are made of 2-different alloys joined together at the sensor, typically, copper-constantan, chromel-alumel, iron-constantan, etc. When the junction sensing heat at the cat is at a higher temperature than the junctions connected to the circuitry, a voltage is produced. A solid state temperature at the sensor at the circuitry end measures the temperature at the circuitry end. The circuity senses this voltage change and converts and amplifies it. If the cats are at the same temperature as the circuity, there will be no voltage. When the exhaust gases heat the sensor end, a dc-voltage will result. The circuitry will sense the level of voltage and if it is above a certain value, the slow down light for that sensor will be enabled. | ||
| Michael N. (Man90tr)
Member Username: Man90tr Post Number: 793 Registered: 4-2001 |
Ed.p, The point here is without cats the slowdown light can be ignored. Remember it is temp swtich like anything else and it has a range of operation regardless of what the manufacturer says. Yours could be tripping at the low range. A little too much fuel in the system that heats up the cats and shuts down a bank etc., etc. could also be a loose connector that is tripping the system. Without the cats and the associated sensors and wiring - running a bit rich in extreme temps is fine and the fire harzard is also gone. Took mine off the TR 2 years ago-- car runs 5 - 10 degrees cooler and oh the awesome racecar sound and no fire hazard. Michael | ||
| James I. Movich (77_308gt4)
New member Username: 77_308gt4 Post Number: 19 Registered: 2-2003 |
every additional data point helps, thanks all. | ||
| James I. Movich (77_308gt4)
New member Username: 77_308gt4 Post Number: 18 Registered: 2-2003 |
Ed, please do let us know what he says | ||
| Ed P. (Ebp)
Junior Member Username: Ebp Post Number: 200 Registered: 12-2002 |
James... I'm not sure at this point if the hot cat and the slow light are a sympton or the cause of the problem. My engine was not running any hotter than usual at the time. I'll know more when my mechanic gets his hands on it. | ||
| tony hopkins (Tonyh)
New member Username: Tonyh Post Number: 44 Registered: 12-2002 |
i've had a tubi fitted to my 355 spider with straight thru pipes and k & n air filters. prior to that, the engine would run super hot especially in traffic and it's running noticably cooler now. cost was around �2.2 k and i've got cats and old exhaust in case i every sell the car. tony | ||
| James I. Movich (77_308gt4)
New member Username: 77_308gt4 Post Number: 17 Registered: 2-2003 |
Let me see if i get this... i have been following this with intense interest, but have still not heard a definitive solution... True or false: the only single, sure-fire way to ensure no problems with slow down and check engine lights is to remove the cats and stock exhaust and replace them with aftermarket test pipes and tubi/equivalent? this eliminates all of the temperature related problems, cost the same or less, and performs better? please clarify... btw, mine is a 90 348ts | ||
| Ed P. (Ebp)
Junior Member Username: Ebp Post Number: 199 Registered: 12-2002 |
Well, my mechanic can't look at it until tomorrow, but his thoughts on it were very similar to the replies I've recieved on here. I just want to make sure we fix the problem and not just treat the symptom. I have sent out some price requests for cat. test pipe and SS exhaust. Any input on that? Thanks again to everyone here.... | ||
| Michael N. (Man90tr)
Member Username: Man90tr Post Number: 792 Registered: 4-2001 |
Put on some tubi test pipes, junk the cats, never have this problem again and love the awesome racecar sound and extra power. Why spend 2K to replace the one cat, when you can spend less than 2K and replace both cats and eliminate the potential "fire" problem altogether. Just my thoughts. BTW, keep the cats for when you sell the car. | ||
| 89TCab (Jmg)
Member Username: Jmg Post Number: 549 Registered: 9-2001 |
Pretty common problem with our Mondials. When the slow down light comes on, it warns first (solid light) then proactively shuts off a bank (blinking light)as it shuts down the offending bank of cylinders to insure that the cats don't overheat and cause a fire. Cause can be MANY things, from a bad ECU to a bad CAT sensor to loose wires in between. Have it checked by a mechanic, once this happened to me and new O2 sensors took care of the problem. It has also happened in heavy rain but then went away. - JMG | ||
| Henry D. Chin (Hanknum)
Junior Member Username: Hanknum Post Number: 207 Registered: 2-2002 |
It sounds like something caused a misfire and the raw fuel being dumped into the cat caused a meltdown. I would not be surprised if cat is melted and clogged. The cat will have to be replaced (though I've heard of places rebuilding them). But, before you do that find out what caused the mifire. | ||
| Russ Turner (Snj5)
Member Username: Snj5 Post Number: 457 Registered: 2-2003 |
Ed - Beautiful car! Would do the single coil check thing first up. You probably know this, but as an American Spec car (I can tell from the bumper) you only have one catalytic converter. I'm with you on this. I have taken a more extreme preventive measure. http://www.ferrarichat.com/discus/messages/112/307711.html?1062422554 Good luck and let us know! I'm always ready to learn something! best rt | ||
| Ed P. (Ebp)
Junior Member Username: Ebp Post Number: 198 Registered: 12-2002 |
Thanks for the fast replies. Russ, my first thought was what you were saying. I remember another thread with someone else having that problem. I did feel the power come back for a split second at one point.... I hope I didn't do any damage with the exhaust getting so hot... | ||
| Russ Turner (Snj5)
Member Username: Snj5 Post Number: 456 Registered: 2-2003 |
I've never heard of a catastrophic cat failure, but that might do it as well. Let us know what happens! best rt | ||
| Russ Turner (Snj5)
Member Username: Snj5 Post Number: 455 Registered: 2-2003 |
Probably single bank ignition failure, not uncommon. This has happened to me, about three different times. Your car is basically 2 four cylinder engines, connected at the crank. When you lose one of the two ignition systems, you then have one four cylinder engine trying to run the car, while the other dumps uncombusted fuel and air into the exhaust system where it ignites in the cat and makes the whole thing VERY hot. You can check which side does not work by tring to start it using only one ignition coil connected, as it will only run on one side. Do not run it long like this for the above reason. When it doesn't start with one of them disconnected, that one is your good side and the other is on Italian Vacation. This 'single bank ignition failure' in my experience, may be caused by several issues 1. ECU failure - not an issue on your car as you have an 88 with only one ECU 2. Coil failure - can be either the coil or the coil controller doofer on top of the coil. Ferrari sells them as one unot, but the controller is a generic part at NAPA. I forget the #. 3.Cap/rotor failure, less likely, but a possibility. After you check which side is bad, check the cap and rotor. 4.Wires loose - ensure all the connections at the coil are good. Try these things, especially the test to see which side is bad. Of course, I am not a professional and may be totally wrong. Just relaying my experience. This is why I am going to a single distributor system: I hate Marelli. hope this helps, and others may have better ideas. best rt | ||
| Bill V (Doc)
Member Username: Doc Post Number: 426 Registered: 9-2001 |
Ed--I'm not a mechanic, but from what I understand, it does sound like a clogged/ fried/ impaired cat. I think that that's what the slow-down light is most usually illuminated for. Just my 2 cents. Good luck tomorrow. | ||
| Ed P. (Ebp)
Junior Member Username: Ebp Post Number: 195 Registered: 12-2002 |
Here's the story...I was just driving on the highway at a normal cruising speed, everything running great. Then the slow down light comes on and at the exact time the engine feels like it loses half power. So I slow down and the light goes out, but the power is still low. I pull over and smell something "hot". I waited for about 20 minutes , the car starts right up but still feels weak and exhaust sound is very different from the normal sound. I make it home at a slow speed , the slow down light flashes on a few times during the trip. All my gauges were reading normal, but the exhaust was glowing hot when I got home. I let it cool off and then put it in the garage. Obviously I will be calling my mechanic in the morning, but can anyone offer some advice in the meantime? I'm guessing that the cats are fried... Hopefully nothing else. Any input will be greatly appreciated... Thanks |