1. Plan to check ECU to ECU tomorrow. 2. Checked across 120 ohm lines; read 60 ohms Also checked resistance (through the OBD connector) of CAN bus high and low across grounds. Would the results be of any significance?
I don't know if that's a check of anything in particular. You wouldn't want the CANBus wires to be shorted to ground (outside of the ECUs). Inside the ECUs are transmitters and receivers (probably transistors or ICs) with complex circuits. Google tells me that the resistance to ground should be high (Mohms) or open circuit.
Can high to signal ground was “only” 1.7 Kohm while can low to signal ground was orders of magnitude higher: 22 Mohm. I had another 360 to test, I’d do an A-to-B comparison. It only took about 5 minutes.
Is it the same on both CAN Busses? i.e. the RH/LH inter-ECU Bus (pins 61 & 45) and the ABS/F1/RH ECU(only) CAN Bus (pins 12 and 29)?
Plan to check 1L and 1S, on the pins you indicated, after swapping the crank sensors. Incidentally, the WSM is showing colors B, N, & V for connector 18G and B & V for connector 14G. On my car, B is actually white, V is actually green, and N is actually black, so it looks like someone forgot to translate into English. B is Bianco (white), N is Nero (black), and V is verde (green). Just another reason why using WSM for electrical issues is difficult.
1. So 1S and & 1T are the inboard plugs, R and L ECUs (respectively) ? 2. Do 1S and 1T access the base fuel map in ROM? I’m assuming it’s one map for both ECUs. 3. Is the fuel map accessed via the CAN Bus? I hope questions make sense; this ECU stuff is not my strong suit. I’m just your basic gearhead
Sorry, I think I've mixed up my inboard/outboard. I thought the plugs were mirrored, but they're not.: 1S is inboard right 1T is outboard left 1L is outboard right 26L is inboard left My diagrams are correct.
Did you do an ECU to ECU check on the CAN Bus wires? https://www.ferrarichat.com/forum/posts/150087953/ I may have given you the wrong inboard/outboard plugs to check. You would have to use RH outboard plug 1L and LH inboard plug 26L No idea. What plug/s do the experts use for reprogramming the ECUs? OBD2 wiring? Or CANBus wiring on the bench?
Are you asking if the LH ECU uses the programming in the RH ECU when the engine is running? As Mitch said, it's possible for one bank to run in open loop and the other in closed loop. That being the case, it seems more plausible that the ECUs have their own maps so they can do this.
1. Not yet. I plan to replace the crank sensor first. Thanks for the link. 2. I’ll see if the ECU repair guy will tell me.
I believe Mitch said that each ECU has its own flash ROM, which implies that each ECU has its own set of maps. That makes sense to me because if one ECU shared from the other, you’d be introducing latency into response from sensor input. But if they do share, I assume they’d have to share via CAN bus, which is why I have interest in knowing how the CAN bus works. The other reason I’m interested in the CAN bus is that LTFT, Bank 2, does not reset to zero when I clear the P1125 error. I’m assuming that the long-term fuel trim value is held in keep alive memory, and the scanner resets the KAM via CAN bus through the OBDII port. The odd thing is that the long-term fuel trim does change upon clearing the code, but it does not change to zero. It always resets to 8.6. BTW: The ECU’s were fine when installed in another vehicle. BTW2: An ECU expert told me only one ECU has ROM.
As I mentioned, I'm going to replace the LH crank sensor ("Angular Speed Sensor") and also check the connection between the sensor and outboard left connector 1T. Below is my connection trace from the sensor to outboard left 1T; please let me know if you agree with the pin numbers. The convention I'm using below is: From (Connector Number, Pin Number) To (Connector Number Pin Number) (Wire Color). 13T,P2 > 1T,P59 (VG) 13T,P1 > 1T, P10 (S) So it's Pin 2 on the sensor to Pin 59 on the ECU connector, and Pin 1 to Pin 10. It think.
What are you trying to solve / fix ..I may have missed it since this thread was originally a different topic
Trying to resolve P1125. I suspect that Bank 2 commanded injector duration is too short. When Bank 2 is inducting 55.8 lb/hr, commanded injector duration is 2.7 ms. When Bank 1 is inducting 54.0 lb/hr, commanded injector duration is 3.0 ms. The durations were measured at warm idle. So Bank 2 is inducting 3% more air mass but the injector duration is 10% less. Disconnecting the MAFs makes no difference. I assume that the short duration induces a lean mixture because Bank 2 injector duration is increased by positive fuel trim. When LTFT gets to ~18% P1125 is thrown. A secondary issue is that, upon clearing the code, the LTFT goes to 8.6 % (not zero). When placed on another 360, the ECUs work fine; fuel trims being ~zero.
Did you swap upstream O2 sensors, check for intake runner leaks , intake leaks in general, exhaust leaks before cat ?
Yes, the common issues were checked. However, not sure I understand how any of the aforementioned items would change the commanded base fuel duration.
Each one of the items would alter what the computer is seeing in air flow this adjusting the fuel accordingly
Fuel trim is a reaction to O2 activity. O2 activity is caused by O2 levels in exhaust. Vacuum leaks and incorrect cam timing cause unusual levels of O2. Been doing this nearly 50 years and was shop foreman in worlds biggest dealer service department. I sure wouldn't be paying attention to CAN lines.
1. Cam timing: 653 and 653 2. 4 gas analysis: I agree that a solution is unlikely without some advanced analysis. Probably a 99% chance that I will end up sending the car to a professional who has the right knowledge and the right tools. But in the meantime, I am learning a thing or two.
Close but hardly correct. BFD. What about the intake cams? You are not diagnosing. You are playing mechanic.
