Hi all, I am relatively new to F355 ownership (3 months), and I was hoping for a longer honeymoon (yeah, I knew what I was getting into with a 355, but I do love the car and enjoy working on my own stuff) ... but the car has me stumped. Background on car - all mods done by previous owner who took good care of the car: 95 F355 Berlinietta, Motronic 2.7 ECU has aftermarket chips Stock cats were '"converted" to test pipes Fabspeed headers with ceramic coating Exhaust bypass valve removed Valve job with updated hardware by Ferrari dealer It had it's 30 K service about 5K ago For what it is worth, it had a good PPI by a reputable dealer. This is the problem: Car running well but had intermittent 1-4 CEL for about 200 miles (on for a few seconds, then a few minutes). It finally stayed on. Checked the codes and got, in this order 4121 - Cat thermocouple (dose not cause CEL illumination according to shop manual) 1114 - Lambda sensor (does light CEL) 4131 - A/C Compressor on/off (does not cause CEL illumination, AC working fine and idle was okay with and without AC on) 4121 - again. Side note: 500 miles before this problem the 5-8CEL lit up and threw a bunch of lambda codes. I changed the 5-8 O2 sensor which fixed the problem. I got a Ferrari O2 sensor from Ricambi, deciding to be conservative since this was my first Ferrari repair. I figured the 1114 code was my problem. For the 1-4 side I decided to follow some F-chatters advise and got a Bosch 15727 generic O2 sensor (and save $200). I took the old connector and used the Bosch wire splicing connector that came with the sensor to hook it all up. The car started right up, and ran okay for a minute or so, then it started popping and missing, and the idle, which was at about 1000, jumped to 2000. The 5-8 CEL came on, and I quickly turned off the car. All the old CEL codes on 1-4 were there, no new numbers were present. I called Ricambi and got another new Ferrari O2 sensor - perhaps the Bosch was not compatible - the tip did look different, but that had been noted in another post. After I installed the Ricambi 02 sensor and started the car, it ran okay for several minutes. My plan was to idle it ten minutes for the ECU to "relearn" as prescribed in the shop manual. At start-up only the 1-4 CEL was on. About 8 minutes into the idle the engine went from a steady 1000 RPM to about 2200 RPM by itself, it ran rough, and the 5-8 CEL came back. Now the dirty laundry: When first disassembling the air intake, the top cover did not want to budge off of the MAF sensor. I took a bit of WD-40 and put it on the joint, and gently pried the two apart with a screwdriver covered with tape. Then when I finished the job I put a thin film of WD-40 on the sleeve of the airbox. Once the problem arose I wondered if the WD-40 had contaminated the hotwire in the MAF (had I thought of this before I started...). Having worked with many hotwire and hotfilm devices like this in wind tunnels for a long time, I knew that contaminating the wire could effect the MAF sensor reading, and perhaps once the computer started "relearning" it was getting a false reading. So, I took the MAF out of the car, and with extreme care took off the end meshes and cleaned the thin film and Nicrome wire with hydrogen peroxide on a Qtip. I also cleaned the remaining interior of the MAF (which did have some oily film come off), and took the screens to the kitchen sink to be thoroughly washed. Then I sealed each end with Saran wrap and used CRC contact cleaner to clean the connector. I put it all back together (and I did remove the Saran wrap!) and started her up. Again, at first she ran okay. The first minute the RPM bounced around 1000 RPM (up and down by about 100 RPM), then settled at 1000. After five or six minutes the engine jumped to 2000 RPM, and the 5-8 CEL came on again. Also, as the engine ran I heard three or four light clunks - which I had not picked up before. The engine started racing just after one of these. (Oil pressure was normal). So then I was back to checking the 1-4 CEL codes. The ECU gave numerous 4121 codes, and a single 1114. I tried to reset the ECU by holding the button for over 10 seconds, but the ECU would not reset. It kept giving me 4121 codes, and on occasion a 1114. But these were deep in the list, and I presume they were left over from before. So, I don't know if I have missed something obvious, did something really stupid, have I screwed up the MAF, is the ECU running amok or should I throw in the towel and get a pro to start wrenching? - not my style but I still has a lot to learn about this car! Any thoughts or suggestions would be very welcome.
On the double 4121 - as you progress through each code, the next one pops up. At the end, you get the three solid blinks, then she cycles through all the codes again. So I'm thinking you just got the first code (4121) again, not a double entry. Timing is everything on refreshing /erasing the ECUs. the 4131 - I had it. It went away by itself. As for O2 sensors, I read too many negative things about wiring generics up so I just bought the right Bosch ones for the car..
Thanks Clyde, I found the fuse for the ECU, so I pulled it to reset it. I haven't had time yet to check it out, will fire it up tomorrow and see if that helps. Rich
On the 348 2.7 the 4121 code is for the cat temp ecu signal. It means the Motronic isn't seeing the signal. It could be that you have a bad cat ecu/s. On the 348 2.7 you can disconnect the cat ecu's and the engine will run just fine. I have been running my 348 for years without the stupid things hooked up. The other thing you should check are the crank position sensors. If they get dirty/oily they can wreak all sorts of havoc. When you check the crank sensors be sure to also check the condition of the wires understand the rubber boots.
Thanks for the tips Ernie. I got it working by resetting the ECU via pulling the fuse. I started her up and let it run for about 15 minutes. All lights were off and she ran smoothly. It was already dark so I decided not to tempt fate and take it out for a drive, but I did move back and forth in the driveway normally - last time I tried it almost stalled out every time I pushed in the clutch. Four minutes of no CEL light Ferrari ownership! so, what did I learn; a. Use of Bosch generic O2 sensor - undetermined. And now that it works I am not going to experiment. b. Pretty sure dirty MAF sensor from foolish use of WD40 was root of problem after O2 sensor replacement . It can be cleaned, very gently. c. Completely clear the ECU by pulling the fuse. It's a start to my education...
Your learning process has begun! You are going at these things the correct way. You are coming on here and not only giving the problem, but also the car model info and the codes you have pulled. This goes a long way on getting help here. Many times I have seen new people come on and just say that they have a CEL. Then ask what caused it. So great start! I too had a bad exhaust ecu and just unplugged it. I am not running my cats so it does not matter anyway.
one issue with the 355 that a lot of people overlook, they spend tons of money replacing items that do not need replacing. I have worked on enough of these cars to figure out some inexpensive fixes that are masked by problems that seem to be the norm on these cars when the whole time it was something simple. Check your CAT Temp ECU, little black boxes at the rear right of the car and the rear left upright. If the resin that seals the electronics is separated from the the plastic housing moisture will get inside and the ECU will send false signals to the computer and release the codes you are receiving. I have changed out several of these little buggers at a fraction of the cost of replacing cats etc and it has always been the culprit. HOWEVER in some cases there are real problems that need to be addressed. Just check the Cat temp ecu's first Wade
On my 2.7 355 the 5-8 CEL comes on when I'm standing still or in lot of traffic but as soon as I'm building speed the light comes off. It also comes on very quickly when I'm up in speed but goes after a couple of seconds. I need to pull the codes and see what the problem really is.
I have them come on and off as they please. Wired bypass valve open triggers the 5-8 and the 1-4 is intermittent. Simple fix; Black tape cover's the annoying dash lights, & drive like a bat out of hell.
Finally got some time to drive the car. The 1-4 light, which started this whole issue is now off, and the 5-8 is intermittent, coming back with 1211- lambda regulation and 1212-lambda reg multiplicative value for self adaption. Given that the O2 sensor has less than 300 miles, I am wondering if it might be a bad reading from a dirty MAF sensor. As I understand it the MAF and O2 sensor both feed parameters into the ECU for the feedback control circuit. Have to do some research on this. Also, I am wondering if I have been too easy on the throttle. The exhaust smells quite rich, and I was doing a bunch of 45mph driving in 6th at 2K RPM or less. Today I kept her over 3K, and saw 70mph a few more times than I was comfortable with due to the local police department. Also, like CGH mentions, it does seem to be more prevalent to get the light at lower speeds or when I stop. Then it goes out at speed. I appreciate the tip on the cat temp sensor ECU, I'll check it out. Given that the cats are gutted I'm not worried about damaging them. Black tape is intriguing, but my first 1500 miles were light free, I'm sure that I can get back there consistently with some more detective work. Thanks guys
I just noticed in your original posting that the car has aftermarket ECU chips. Having some prior experience in the engine tuning world, I think you should consider getting a set of stock chips (if indeed there were more than 1 swapped out) back in the car so you can eliminate that variable. Engine mapping is really a big variable based on the symptoms you are reporting. Good luck!
That's a good thought. I have the original chips, so it is an easy option. I put 40 miles on her yesterday. At the start of the drive the 5-8Cel would come on, mainly at slow speed or lights. I kept the revs in the 2800 to 3400 range with pulls to 6000 when I felt it wouldn't lead to traffic court. By the second half of the drive the light was staying off. I am still learning this car's personality (of which there is no lack of!). Thanks
The "gold connector kit" was design to first provide good connection so that we don't chase ghosts. Many good parts have been replaced because we thought they were bad.
I have been reading about those gold connector kits on F-Chat. Given the age of the car it is definitely something I am going to do. Many thanks for the comments and suggestions.
Before you go and waisting money on some pins try removing and cleaning the mafs first. Then make sure the mafs are set to 383ohms. The other thing that can cause a lambda is a faulty coolant temp sensor, so have a look at those too. You may also want to look into getting your fuel injectors cleaned.
Exhaust bypass valve removed = put the valve back in. I was pulling codes left and right always under 3K rpm. Anything over this less of a problem. Fernando had me put back in the valve = codes gone. He explained it this way: With the valve missing the exhaust travels the path of least resistance, hence the upper cats. This then limits the amount of exhaust gases passing over the 02 sensors causing a trip in the system. 700+ miles now with not a code shown. I can run at any RPM with no issues at this point. Just a possibility that worked for mine.
reviving this from the dead… I’m noticing the same issue on my 2.7. Have a valve controller and whenever the valve is open, I get CEL lights under 3k rpm or when idling. Any way to fix this, or should I just ignore CEL’s knowing it’s because of the valve being open? I read everywhere that 2.7 shouldn’t have CEL’s with the valve open since there are no sensors post valve. Maybe others are having the same issue?
So 1211 Lambda regulation (both banks) and 1111 MAF (LH bank). I guess you could swap the MAFs to see if the 1111 fault transfers to the other side. I would wait for a second opinion for the other code. I don't know if the bypass valve messes with air/fuel ratios.
My car is a Euro 95 with 2.7 Mototronic. I have a Capristo valve, capristo exhaust and a Capristo remote and it throws a CEL as soon as I open the valve manually and staying on the hole time until i close the valve again. The ECU notices that the exhaust valve is opened outside the normal parameters and throws a CEL. As farvas i know absolutly normal ( owning my car over 10years)...friends with 355s telling the same
Since the 2.7 system doesn't have a 3rd thermocouple for measuring the bypass valve state, the RH Motronic ECU might be monitoring the voltage/current on the wire going to the bypass vacuum solenoid valve. If so, these aftermarket controllers might be upsetting the voltage/current on the wire. Bad controller design?
Exactly, but a wouldn't say it's a bad remote design. The ECU 5-8 controls the opening of the exhaust valve over selected gear and the rpm. As you mentioned, the eletric signal to open the bypass is noticed by ECU. I don't know how to get rid of the CEL with an other design of remote controller. It will still use an electric signal to open the valve outside the standard parameters and this will trigger an CEL. I' am ok with the CEL, as long it's just temporarly and because of the remote controller
Thanks all! I initially wired the valve open all the time just to hear what it sounded like, and had the same issue even after getting the valve controller. I don’t believe it’s a controller issue. Interesting that @blox79 has the same issue and also has a capristo exhaust.
