LS1 Swapped 240SX Bank 2 40% Extra Fuel issue
10-04-2016 | 11:48 PM
#1
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Teching In
Joined: Jan 2016
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From: Chicago, IL
LS1 Swapped 240SX Bank 2 40% Extra Fuel issue Hey everyone! I have a 1995 Nissan 240SX swapped with a LS1/T56 from a 2000 Camaro SS. The mods done on the engine is a Texas Speed 228R, PAC Valve Springs and Comp Cams Hardened Push Rods, and a Wiring Specialties LS1 to S14 240SX harness. When the engine was swapped it was initially tuned with HPTuners just to move in and around of the garage because it was not road ready at the time. I eventually ran into low oil pressure problems (faulty oil pump, oil pump pickup tube sitting too low in sump and o-ring not seating correctly into oil pump) and sent it to a shop to have that sorted out, along with a few other odds and ends like custom brackets and such. With the oil pressure issues sorted out, it got sent out to tuning and they ran into an issue where the Bank 2 O2 was not reading correctly (Bosch O2), they replaced the O2 and it still wasn't reading correct values so it was dumping 40% extra fuel into Bank 2. They believe there is an issue with the continuity in the wiring for Bank 2 O2, coil packs, or injectors. The car idles and drives around, just runs pig rich.
Any and all input is appreciated!
Any and all input is appreciated!
10-06-2016 | 07:30 AM
#3
° Check for exhaust leaks. Probably the #1 cause of disparity between O2 readings.
° Make sure that you don't have the O2 sensor's cross connected. Driver's side (Bank 1) connected to driver's side harness plug and vice versa.
° Make sure that you don't have the O2 sensor's cross connected. Driver's side (Bank 1) connected to driver's side harness plug and vice versa.
10-12-2016 | 01:45 AM
#4
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Teching In
Joined: Jan 2016
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From: Chicago, IL
UPDATE:
Went to the shop today to help with the diagnosis. To start things off, Bank 1 STFT was +/- 5%, Bank 2 STFT was hovering around 40-48. On a Snap On Scanner, on the fuel trim data menu it showed that my IAT was -40 F, but on the engine data menu it showed that it was 86 F. We checked for continuity in those wires and they were fine, we replaced the IAT as well. Opened up the PCM, everything looked great, no corrosion. Did a smoke test to check for leaks and none were to be found. I don't quite remember how we got to this point but we managed to drop Bank 2 STFT to around 25%. We then removed the MAP sensor and plugged it with a finger and this put the Bank 2 STFT at +/- 5%, we then put the MAP sensor back in and the trims were really good and the car idled great. Before removing the MAP, it threw no codes for anything MAP related. We let the car cool off for an hour or so and we tried again. Bank 2 STFT climbed up to 18 and would reset itself to 0 if there was any throttle movement. At the end of the day, we checked for DTC's and ended up with
P0140 Low O2S Activity Bank 1 Sensor 2
P0160 Low O2S Activity Bank 2 Sensor 2
P0412 Air Switching Valve "A" Problem
P0418 Air Pump Relay Control Circuit Problem
P0645 A/C Compressor Clutch Relay Control Circuit
P1637 Generator L-Terminal Circuit
So at this point it was clear that during the start up tune, the tuner did not delete AIR and rear O2 sensors and to be honest, I don't think he even did any tuning for the cam. Another thing to note is that my headers and y pipes are joined with V-bands that do not line up correctly, on the driver's side it is sealed better than the passenger side and there is a small leak just about 3 inches downstream from the Bank 2 O2. The exhaust is getting fixed tomorrow. Will report back with any future updates.
Went to the shop today to help with the diagnosis. To start things off, Bank 1 STFT was +/- 5%, Bank 2 STFT was hovering around 40-48. On a Snap On Scanner, on the fuel trim data menu it showed that my IAT was -40 F, but on the engine data menu it showed that it was 86 F. We checked for continuity in those wires and they were fine, we replaced the IAT as well. Opened up the PCM, everything looked great, no corrosion. Did a smoke test to check for leaks and none were to be found. I don't quite remember how we got to this point but we managed to drop Bank 2 STFT to around 25%. We then removed the MAP sensor and plugged it with a finger and this put the Bank 2 STFT at +/- 5%, we then put the MAP sensor back in and the trims were really good and the car idled great. Before removing the MAP, it threw no codes for anything MAP related. We let the car cool off for an hour or so and we tried again. Bank 2 STFT climbed up to 18 and would reset itself to 0 if there was any throttle movement. At the end of the day, we checked for DTC's and ended up with
P0140 Low O2S Activity Bank 1 Sensor 2
P0160 Low O2S Activity Bank 2 Sensor 2
P0412 Air Switching Valve "A" Problem
P0418 Air Pump Relay Control Circuit Problem
P0645 A/C Compressor Clutch Relay Control Circuit
P1637 Generator L-Terminal Circuit
So at this point it was clear that during the start up tune, the tuner did not delete AIR and rear O2 sensors and to be honest, I don't think he even did any tuning for the cam. Another thing to note is that my headers and y pipes are joined with V-bands that do not line up correctly, on the driver's side it is sealed better than the passenger side and there is a small leak just about 3 inches downstream from the Bank 2 O2. The exhaust is getting fixed tomorrow. Will report back with any future updates.