| Author | Message | ||
| Jim Hilton (Colo348)
New member Username: Colo348 Post Number: 36 Registered: 5-2003 |
Todd, I just went though this last weekend. I was driving slowly and it was pretty cool out, but the 1/4 slow down came on? I read my service and owners manuals and surmised that I might be getting too much O2 thus screwing up the cat sensor or exhaust ECU. I have recently installed a Tubi system and on the 1/4 side I left the manifold to cat and cat to Tubi pretty loose to make sure the system was centered correctly before tightening all bolts. When I tighten the 1/4 side to match the 5/8 side no more slow down light. May be it's something dumb like this? Good luck, Jim Hilton | ||
| todd montandon (Sllade)
New member Username: Sllade Post Number: 34 Registered: 7-2003 |
jeff would you suggest i just buy new ecu's or just unplug them? | ||
| Jeff B. (Miltonian)
Member Username: Miltonian Post Number: 429 Registered: 12-2002 |
Unplug both of the connectors coming from the Temp ECU's, at least as a test. The "Slow Down" lights won't come on any more. Remember, if the ECU's are disconnected, and you really have a problem, you get no warning. In an extreme case, the catalysts could overheat and cause a fire in your engine compartment. From what I have read, about 99% of the cases of "Slow Down" lights coming on are false readings. And the ECU's are sealed, not repairable. There are lots of good diagrams in the factory parts manual, I enjoy posting pictures for those who don't have access to a copy. | ||
| todd montandon (Sllade)
New member Username: Sllade Post Number: 29 Registered: 7-2003 |
jeff what book do you keep showing me I would love to have it todd | ||
| todd montandon (Sllade)
New member Username: Sllade Post Number: 28 Registered: 7-2003 |
jeff do i unplug the thermal coupler or the ecu? | ||
| Jeff B. (Miltonian)
Member Username: Miltonian Post Number: 426 Registered: 12-2002 |
Asking questions doesn't make you an idiot. The thermocouple is #47, located on the bottom of the catalyst. The exhaust ECU is #37, and they are located right next to the rear coil springs, kind of hidden, but not hard to find. Look behind where the spark plug wires are plugged in. You don't have to look from the ground, just open the engine lid.  | ||
| todd montandon (Sllade)
New member Username: Sllade Post Number: 25 Registered: 7-2003 |
jeff remember i am a mechanical idiot sevant where are they to unplug can i see them from the ground | ||
| Jeff B. (Miltonian)
Member Username: Miltonian Post Number: 424 Registered: 12-2002 |
DISCLAIMER: Attempt at your own risk!! That being said, there is a thermcouple in each catalytic converter. It reads the exhaust temperature and sends a signal to the exhaust temperature ECU. The ECU processes the information and sends a signal to the main ignition/injection ECU (one per bank on each of these components). If the thermocouple reads a "hot" catalyst (probably due to the engine running excessively rich), the ECU tells the main Motronic module for that bank to cut back the fuel supplied, and turns on a warning light ("Slow Down"). The problem is that the Temperature ECU's are junk, and give false signals. And they're about $200 each. They have nothing to do with the operation of the engine, they are just for warning purposes. If you unplug them, it has no effect on the way the engine runs, but you no longer have the protection provided by the system. Replacing the temp ECU takes about two minutes. The new ECU's are supposedly better, but who knows? | ||
| todd montandon (Sllade)
New member Username: Sllade Post Number: 24 Registered: 7-2003 |
vince do you have carbon fiber on you 348 i thought i saw a pic of your dash in the archives | ||
| todd montandon (Sllade)
New member Username: Sllade Post Number: 22 Registered: 7-2003 |
jeff can you unplug them will it harm the car | ||
| Jeff B. (Miltonian)
Member Username: Miltonian Post Number: 422 Registered: 12-2002 |
The "Slow Down" sensor light problem is probably the #1 complaint on 348's, due to faulty exhaust temperature sensor ECU's. There is a ton of info on this in the archives. I bought new ones, but if I had to do it over, I would just unplug them... | ||
| Vincent (Vincent348)
Member Username: Vincent348 Post Number: 789 Registered: 4-2003 |
Amen!!!! Drive it and she'll be happy. I like the three piece rims. The 355 wheels look good on the 348. Vincent. | ||
| todd montandon (Sllade)
New member Username: Sllade Post Number: 19 Registered: 7-2003 |
vince where do you live i'm in san diego my number is 619 589 1530 or 619 444 3743 | ||
| todd montandon (Sllade)
New member Username: Sllade Post Number: 18 Registered: 7-2003 |
vince what kind of wheels i was thinking about 355 wheels its black on tan. well the door cost me 350 to have fixed the guys at symbolic told me that alot of times people do more damage not driving these cars than they do by driving them they were made to drive not sit. | ||
| Vincent (Vincent348)
Member Username: Vincent348 Post Number: 786 Registered: 4-2003 |
todd, Is the mech paying for the fixes? What colour is it? I am not much for tricking out, but to each is own. I like black on black. I am thinking of upgrading my exhaust though and considering 18" wheels at some point. Vincent. | ||
| todd montandon (Sllade)
New member Username: Sllade Post Number: 16 Registered: 7-2003 |
vince i just love the look of it it has 42000.mi on it i have all the records and had the mechs sign a letter ststing it was in absolute 100% mechanical condition.i want to trick the shi- out of it any sugesstions I think i am going to use suede on the seats bolsters and maybe all the wrap around dash and door panels what do you think | ||
| Vincent (Vincent348)
Member Username: Vincent348 Post Number: 785 Registered: 4-2003 |
I've stopped at the same del taco, though I managed to get the door open.  If the engine sounds the same, just drive it. (at your own risk of course, I am not a mechanic) but that worked for me. These cars, especially 348, are a little quirky but a lot of fun!!!! It's a Ferrari. Also, you may want to unplug and plug back in the sensors leading to the air intakes on top of the engine, I fiddled with mine and the light went away. Why did you pick a 348? How many miles are on it? Vincent. | ||
| todd montandon (Sllade)
New member Username: Sllade Post Number: 15 Registered: 7-2003 |
well hot damn thanks vince i will pass that info on cause noone in san diego knows that I have the car at symbolic motors right now I blew a door actuator on the ride home from vegas got just a little pissed when i had to climb out the window at del taco infront of everyone at a muscle car show that happened to be going . the car doesn't drive different when the lights come on | ||
| Vincent (Vincent348)
Member Username: Vincent348 Post Number: 780 Registered: 4-2003 |
Todd, The sensor is on top of the catalytic converter. Does your car feel any different when the light comes on? I'm not sure how you check other than swap them from side to side and see if the the check 5-8 will come on instead of the 1-4. The thingies are there to put your seatbelt when getting out of the car. Makes it easier to get in and out. have you posted a pic of the new beast? Vincent. | ||
| todd montandon (Sllade)
New member Username: Sllade Post Number: 13 Registered: 7-2003 |
vince where is this sensor located and how do i check to see if its bad? also do you know what the two tits infront of the rearview mirror r for | ||
| Vincent (Vincent348)
Member Username: Vincent348 Post Number: 777 Registered: 4-2003 |
Todd, I went through a period on mine where the check eng. lights would go on, stay on for 50mi., go off, come backon for a few....etc. The engine sounded the same and the car behaved well. I was told to "just drive it". My problem has gone away by itself. Though in many cases it seems from archived threads that the problem lies with the sensor. Challenge cars are set up in race trim w/ safety equipment. Vincent. | ||
| todd montandon (Sllade)
New member Username: Sllade Post Number: 12 Registered: 7-2003 |
what sensor should i check the lights come on like the slow 1-4 then the slow 4-5 but they stay on only for a few seconds then go out. i was told if i was not driving it hard not to worry about it butm sounds like b.s. to me i,m not very mechanical but will learn. Also whats all this challenge stuff everyone is talking about | ||
| j scott leonard (Jscott)
Member Username: Jscott Post Number: 501 Registered: 1-2002 |
Check the sensor. There are many threads on this problem. I had it in my 328 and it was a bad sensor. I understand it is the same in the 348. I have 348 as well but the problem hasn't occured in it. Is the light problem off and on or constant? Check the archives for several threads that will help. | ||
| todd montandon (Sllade)
New member Username: Sllade Post Number: 10 Registered: 7-2003 |
i have a 348 91 the slow down sensor lights keep coming on when i'm not driving very hard at all could this be a ecu problem or what when i drove it home from vegas they came on quite a bit but it was hotter than he-- i know that it goes off the exhaust heat or maybe i was told a fib but what could this be help |