Datalogging Code 44 Left o2 Sensor Lean - NJFBOA - Home of New Jersey's Camaros and Firebirds

Teds89IROC · 08-27-2019, 11:35 AM

Last month the car threw both codes- Left and Right o2 Sensors Lean. It was running very rich, plugs looked fouled. Checked fuel pressure, it was sub 35psi- checked the regulator. Had slight fuel smell in the diaphragm so I replaced it. Fuel pressure improved but not the main issue. I also cycled the fuel pump with the injectors out of the intake manifold and none were leaking. Changed the fuel filter, bingo. Changed the plugs went for a ride and all seemed well for about a half hour. Car started to bog coming to a stop, smelled rich again. Drove maybe another 15 minutes with no SES light until I was parked idling for a bit -Code 44 Left o2 Lean. I cleared the code, setup a datalog and drove a bit. Car was behaving the same but no SES light until I got back home sitting parked - Code 44 Left o2 Lean.

The only thing that looks to be pattern is at idle, the Left LT Fuel Trim is at max 160 while the right side looks good, around 130. The other data set I have doesn't show vehicle speed but driving under load (looking at the RPM's) it seems both sides are all over the place. I'd prefer not to just throw two new o2 sensors at it but nothing seems to pinpoint the issue unless I'm missing something. I noticed a slight exhaust leak at the collector but the o2 sensor is upstream from it. I also checked for burned or damaged wires and all looks good there. Any ideas?

Record Data
FRAME: 0 TM: 0.0
A.I.R. PUMP OFF
AC CLUTCH OFF
AC EVAP(°F) 20
AC PRESS(PSI) -13.12
AC PRESS(V) 0.02
AC REQUEST OFF
BARO("HG) 29.86
BARO(V) 4.82
BATTERY(V) 13.6
LT FUEL TR CL 16
LT FUEL TRM L 160
LT FUEL TRM R 137
EVAP DUTY(%) 0
COOLANT(°F) 177
EGR DUTY(%) 0
EGR VLVPOS 1
ENGINE(RPM) 850
KS COUNTER 2500
FC1 RELAY ON
FC2 RELAY OFF
IAC POSITION 48
IDLE REQ(RPM) 875
INJ L PW(mV) 4
INJ R PW(mV) 0
KNOCK RET(°) 0
LOOP STATUS CLSD
MAF(gr/S) 9
MAP("HG) 16.79
MAP(V) 2.53
IAT(°F) 122
O2S LEFT(mV) 471
O2S RIGHT(mV) 591
RUN TIME 24:38
SKIPSHFT ENA NO
SPARK ADV 26
THROTTLE(%) 0
TPS SENSOR(V) 0.49
VEHSPEED(MPH) 0
------------------------------
FRAME: 1 TM: 3.6
A.I.R. PUMP OFF
AC CLUTCH OFF
AC EVAP(°F) 20
AC PRESS(PSI) -13.12
AC PRESS(V) 0.02
AC REQUEST OFF
BARO("HG) 29.86
BARO(V) 4.82
BATTERY(V) 13.6
LT FUEL TR CL 16
LT FUEL TRM L 160
LT FUEL TRM R 155
EVAP DUTY(%) 0
COOLANT(°F) 177
EGR DUTY(%) 0
EGR VLVPOS 1
ENGINE(RPM) 1375
KS COUNTER 2500
FC1 RELAY ON
FC2 RELAY OFF
IAC POSITION 70
IDLE REQ(RPM) 875
INJ L PW(mV) 13
INJ R PW(mV) 9
KNOCK RET(°) 0
LOOP STATUS CLSD
MAF(gr/S) 12
MAP("HG) 8.18
MAP(V) 0.96
IAT(°F) 122
O2S LEFT(mV) 58
O2S RIGHT(mV) 44
RUN TIME 24:42
SKIPSHFT ENA NO
SPARK ADV 31
THROTTLE(%) 7
TPS SENSOR(V) 0.90
VEHSPEED(MPH) 0
------------------------------
FRAME: 2 TM: 7.2
A.I.R. PUMP OFF
AC CLUTCH OFF
AC EVAP(°F) 20
AC PRESS(PSI) -13.12
AC PRESS(V) 0.02
AC REQUEST OFF
BARO("HG) 29.86
BARO(V) 4.82
BATTERY(V) 13.6
LT FUEL TR CL 16
LT FUEL TRM L 160
LT FUEL TRM R 132
EVAP DUTY(%) 0
COOLANT(°F) 177
EGR DUTY(%) 0
EGR VLVPOS 1
ENGINE(RPM) 1550
KS COUNTER 2500
FC1 RELAY ON
FC2 RELAY OFF
IAC POSITION 64
IDLE REQ(RPM) 875
INJ L PW(mV) 4
INJ R PW(mV) 0
KNOCK RET(°) 0
LOOP STATUS CLSD
MAF(gr/S) 10
MAP("HG) 14.17
MAP(V) 2.04
IAT(°F) 122
O2S LEFT(mV) 231
O2S RIGHT(mV) 448
RUN TIME 24:46
SKIPSHFT ENA NO
SPARK ADV 37
THROTTLE(%) 10
TPS SENSOR(V) 0.80
VEHSPEED(MPH) 0
------------------------------
FRAME: 3 TM: 10.8
A.I.R. PUMP OFF
AC CLUTCH OFF
AC EVAP(°F) 20
AC PRESS(PSI) -13.12
AC PRESS(V) 0.02
AC REQUEST OFF
BARO("HG) 29.86
BARO(V) 4.82
BATTERY(V) 13.6
LT FUEL TR CL 18
LT FUEL TRM L 160
LT FUEL TRM R 154
EVAP DUTY(%) 0
COOLANT(°F) 177
EGR DUTY(%) 0
EGR VLVPOS 1
ENGINE(RPM) 1975
KS COUNTER 2500
FC1 RELAY ON
FC2 RELAY OFF
IAC POSITION 60
IDLE REQ(RPM) 875
INJ L PW(mV) 0
INJ R PW(mV) 0
KNOCK RET(°) 0
LOOP STATUS CLSD
MAF(gr/S) 10
MAP("HG) 12.21
MAP(V) 1.69
IAT(°F) 122
O2S LEFT(mV) 44
O2S RIGHT(mV) 44
RUN TIME 24:49
SKIPSHFT ENA NO
SPARK ADV 28
THROTTLE(%) 0
TPS SENSOR(V) 0.49
VEHSPEED(MPH) 0
------------------------------
FRAME: 4 TM: 14.4
A.I.R. PUMP OFF
AC CLUTCH OFF
AC EVAP(°F) 20
AC PRESS(PSI) -13.12
AC PRESS(V) 0.02
AC REQUEST OFF
BARO("HG) 29.86
BARO(V) 4.82
BATTERY(V) 13.6
LT FUEL TR CL 16
LT FUEL TRM L 160
LT FUEL TRM R 132
EVAP DUTY(%) 0
COOLANT(°F) 177
EGR DUTY(%) 0
EGR VLVPOS 1
ENGINE(RPM) 900
KS COUNTER 2500
FC1 RELAY ON
FC2 RELAY OFF
IAC POSITION 49
IDLE REQ(RPM) 875
INJ L PW(mV) 4
INJ R PW(mV) 0
KNOCK RET(°) 0
LOOP STATUS CLSD
MAF(gr/S) 9
MAP("HG) 16.79
MAP(V) 2.45
IAT(°F) 122
O2S LEFT(mV) 53
O2S RIGHT(mV) 382
RUN TIME 24:53
SKIPSHFT ENA NO
SPARK ADV 26
THROTTLE(%) 0
TPS SENSOR(V) 0.49
VEHSPEED(MPH) 0
------------------------------

DATA SET 2

LT FUEL TR CL 17
LT FUEL TRM L 160
LT FUEL TRM R 160
ENGINE(RPM) 2200
IAC POSITION 86
INJ L PW(mV) 4
INJ R PW(mV) 4
LOOP STATUS CLSD
MAF(gr/S) 35
MAP("HG) 24.20
MAP(V) 3.20
IAT(°F) 93
O2S LEFT(mV) 346
O2S RIGHT(mV) 138
RUN TIME 05:36
THROTTLE(%) 32
TPS SENSOR(V) 1.51
------------------------------
FRAME: 14 TM: 22.6
LT FUEL TR CL 10
LT FUEL TRM L 128
LT FUEL TRM R 125
ENGINE(RPM) 2125
IAC POSITION 90
INJ L PW(mV) 9
INJ R PW(mV) 9
LOOP STATUS CLSD
MAF(gr/S) 57
MAP("HG) 18.64
MAP(V) 2.76
IAT(°F) 92
O2S LEFT(mV) 941
O2S RIGHT(mV) 950
RUN TIME 05:37
THROTTLE(%) 27
TPS SENSOR(V) 1.35
------------------------------
FRAME: 15 TM: 24.2
LT FUEL TR CL 11
LT FUEL TRM L 127
LT FUEL TRM R 125
ENGINE(RPM) 2475
IAC POSITION 90
INJ L PW(mV) 4
INJ R PW(mV) 4
LOOP STATUS CLSD
MAF(gr/S) 63
MAP("HG) 17.77
MAP(V) 2.71
IAT(°F) 90
O2S LEFT(mV) 204
O2S RIGHT(mV) 857
RUN TIME 05:39
THROTTLE(%) 30
TPS SENSOR(V) 1.43
------------------------------
FRAME: 16 TM: 25.8
LT FUEL TR CL 11
LT FUEL TRM L 125
LT FUEL TRM R 123
ENGINE(RPM) 2700
IAC POSITION 90
INJ L PW(mV) 9
INJ R PW(mV) 9
LOOP STATUS CLSD
MAF(gr/S) 82
MAP("HG) 19.73
MAP(V) 2.90
IAT(°F) 89
O2S LEFT(mV) 799
O2S RIGHT(mV) 391
RUN TIME 05:40
THROTTLE(%) 27
TPS SENSOR(V) 0.98
------------------------------
FRAME: 17 TM: 27.4
LT FUEL TR CL 17
LT FUEL TRM L 160
LT FUEL TRM R 160
ENGINE(RPM) 2450
IAC POSITION 88
INJ L PW(mV) 0
INJ R PW(mV) 4
LOOP STATUS CLSD
MAF(gr/S) 39
MAP("HG) 17.44
MAP(V) 3.41
IAT(°F) 89
O2S LEFT(mV) 724
O2S RIGHT(mV) 462
RUN TIME 05:42
THROTTLE(%) 31
TPS SENSOR(V) 1.43
------------------------------
FRAME: 18 TM: 29.0
LT FUEL TR CL 11
LT FUEL TRM L 124
LT FUEL TRM R 122
ENGINE(RPM) 2250
IAC POSITION 90
INJ L PW(mV) 9
INJ R PW(mV) 9
LOOP STATUS CLSD
MAF(gr/S) 52
MAP("HG) 16.79
MAP(V) 2.39
IAT(°F) 89
O2S LEFT(mV) 977
O2S RIGHT(mV) 977
RUN TIME 05:44
THROTTLE(%) 19
TPS SENSOR(V) 1.08
------------------------------
FRAME: 19 TM: 30.6
LT FUEL TR CL 7
LT FUEL TRM L 159
LT FUEL TRM R 137
ENGINE(RPM) 2100
IAC POSITION 84
INJ L PW(mV) 4
INJ R PW(mV) 0
LOOP STATUS CLSD
MAF(gr/S) 24
MAP("HG) 11.56
MAP(V) 1.51
IAT(°F) 89
O2S LEFT(mV) 235
O2S RIGHT(mV) 471
RUN TIME 05:45
THROTTLE(%) 11
TPS SENSOR(V) 0.84
------------------------------

sweetbmxrider · 08-27-2019, 02:55 PM

Usually if you bring the rpms up at idle to about 2500-3k (No vacuum in motor) and your o2 readings come down to desired value, that indicates a vacuum leak. Not saying its the case here, just something to test.

IAC position seems high, iirc around 30-40 at idle was desired. Is it an aftermarket throttle body? Intake manifold? Try doing an IAC reset and see if anything improves there.

I'd say clean the MAF for ****s and giggles. Stock cars, the motor displacement roughly equates the grams/second flow rate. Never looked at a modified car and I'd assume it would flow more, just something I noticed.

Smelling rich and having lean codes present doesn't make sense to me. Wonder if you are having ignition issues. The o2's seems to be switching, we want to see the voltages swing from under .5 volts to over .5 volts. They are constantly helping to adjust afr.

Teds89IROC · 08-27-2019, 03:16 PM

a little background. It was a rebuilt LT1 - 355, probably about 30k on the motor. Added a CC306 with all the necessary valve train components, stock TB, stock heads, stock intake. Long tubes, no emissions - tuned by Brian from PCMforless. Car ran excellent for a couple years until now, so it's something that recently failed.

I was thinking about taking the whole TB off and cleaning everything including MAF. I just assumed I would have gotten a MAF trouble code if that was an issue but never assume, right?

sweetbmxrider · 08-28-2019, 09:09 AM

Yeah, never assume. I would definitely give it all a good cleaning and reset the iac. No egr, correct? I'd still try looking for a vacuum leak as well.

Teds89IROC · 08-28-2019, 09:23 AM

Will do, thanks. And correct, no egr

BonzoHansen · 08-28-2019, 09:37 AM

Quote:

Originally Posted by sweetbmxrider

Yeah, never assume. I would definitely give it all a good cleaning and reset the iac. No egr, correct? I'd still try looking for a vacuum leak as well.

will an exhaust leak trip a lean code?

sweetbmxrider · 08-28-2019, 10:45 AM

Quote:

Originally Posted by BonzoHansen

will an exhaust leak trip a lean code?

Yeah definitely, he just said it was downstream of the o2. I guess it depends how far

Pampered-Z · 09-02-2019, 09:13 PM

What year LT1?

Are you running MAP and MAS?

CHave you checked the PVC isn't stuck?

Teds89IROC · 09-03-2019, 09:46 PM

1995 LT1
MAP and MAF
Haven't checked the PCV. Hoping to get back to this this week.

Teds89IROC · 09-18-2019, 09:03 AM

Some updates:
I worked on fixing the collector leaks and also found some loose header bolts.

I then started checking all the rubber and found a split in the small hose coming from the left of the intake that goes to the Opti (not sure if this a source for vacuum leak).

Checked the PCV valve, it is not stuck but the grommet where it fits into the intake manifold is completely deteriorated and split. (also looks like a lot of oil moving through there - might pick up a catch can)

The nub caps on the TB for the coolant bypass are also cracked all the way through (also not sure if this can be a source for vacuum leak)

Thanks for all the advice, I'll be ordering some parts and reporting back..

ThoR294 · 09-23-2019, 06:57 AM

sounds like everything that can cause a lean code. Good hunting!

the TB coolant bypass will not cause a vacuum leak as that is only a coolant port

Teds89IROC · 03-09-2020, 09:10 AM

Final update for anyone following or if a search takes them here with similar problems. I wasn't throwing a code anymore but it still wasn't right and I hit a wall. I took the car to Josh (JS Performance) and the newer style (plastic) Delco MAF was causing whacky readings as well as a worn out throttle body main assembly. I couldn't see this on my scanner but Josh saw at idle the TPS voltage was jumping around. The computer was correcting false readings and throwing off fueling. Factory style metal Delco MAF and a BBK throttle body and the car is running great! He also did the caster/camber plates and a few other things while I had it there. I picked the car up Friday and have driven it about 100 miles so far.