Engines runs rough with excessive exhaust

Hi,

Assuming everything is okay with the spark plugs and wires (like one wire came off) then you have an issue possibly with the following issues.

Dirty or faulty Mass Air Flow (MAF) sensor.
Faulty oxygen sensor.
Leaky fuel injectors allowing too much fuel into the combustion cylinders.
Worn spark plugs.
Stuck fuel pressure regulator.
Faulty coolant temperature sensor.
Faulty coolant thermostat

https://www.2carpros.com/articles/how-to-replace-a-mass-air-flow-sensor-maf

https://www.2carpros.com/articles/how-to-test-an-oxygen-sensor-02-sensor

https://www.2carpros.com/articles/how-to-test-a-fuel-injector

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

The best way to figure this out is we need to monitor the short term fuel trim data with a scan tool. This will tell us that it is a rich condition which it seems obvious. Then you can look at the MAF voltage to see if it is reading properly. Also, o2 sensor data. Let me know if you have a scan tool that can read live data and I can walk you through what the numbers mean if you need me to. Thanks

I can go pick up a scan tool. So using the scan tool will tell us even without the check engine light right?

Do you think this is a good scanner to get? https://shop.advanceautoparts.com/p/actron-autoscanner-live-data-with-color-screen-cp9670/11022473-P?searchTerm=scanner

Yes. That is a pretty common one that people get. The key thing to look for is not only the ability to read codes but is live data, and the ability to read ABS codes as well. This one can do all of that, so I would go for it.

The info I gave earlier is what you want to look at in the live data section. Worst case, just see if you can export the live data mentioned above while the vehicle is acting up, into a spreadsheet and then upload that. I can review it and let you know what appears to be happening.

1996 OBDII/EOBD

I/M Monitors

Since DTCs Cleared

Misfire Monitor ok
Fuel System Mon ok
Comp Component ok
Catalyst Mon inc
Htd Catalyst n/a
Evap System Mon n/a
Sec Air System n/a
A/C Refrig Mon n/a
Oxygen Sens Mon inc
Oxygen Sens Htr ok
EGR/VVT Sys Mon inc

==============================

DTCs (Codes)

No codes found

==============================

Record Data

FRAME: 0 TM: 0.0

ABSLT TPS(%) 0.0
CALC LOAD(%) 34.1
COOLANT(°F) 113
ENG SPEED(RPM) 988
FUEL SYS 1 OPEN
FUEL SYS 2 N/A
IAT(°F) 95
IGN ADV(°) 26.0
LT FTRM1(%) 0.0
MAF(LB/M) 1.01
MIL STATUS Off
O2S11(V) 0.570
O2S12(V) 0.620
OBD2 STAT CA
ST FTRM11(%) 0.0
ST FTRM1(%) 0.0
VEH SPEED(MPH) 0

------------------------------

Is there some way I can send a PDF file to you? I can't get all of the data on here.

Nevermind. Here is all of the data from the recording. What do you think?

1996 OBDII/EOBD

I/M Monitors

Since DTCs Cleared

Misfire Monitor ok
Fuel System Mon ok
Comp Component ok
Catalyst Mon inc
Htd Catalyst n/a
Evap System Mon n/a
Sec Air System n/a
A/C Refrig Mon n/a
Oxygen Sens Mon inc
Oxygen Sens Htr ok
EGR/VVT Sys Mon inc

==============================

DTCs (Codes)

No codes found

==============================

Record Data

FRAME: 0 TM: 0.0

ABSLT TPS(%) 0.0
CALC LOAD(%) 34.1
COOLANT(°F) 113
ENG SPEED(RPM) 988
FUEL SYS 1 OPEN
FUEL SYS 2 N/A
IAT(°F) 95
IGN ADV(°) 26.0
LT FTRM1(%) 0.0
MAF(LB/M) 1.01
MIL STATUS Off
O2S11(V) 0.570
O2S12(V) 0.620
OBD2 STAT CA
ST FTRM11(%) 0.0
ST FTRM1(%) 0.0
VEH SPEED(MPH) 0

------------------------------

FRAME: 1 TM: 3.8

ABSLT TPS(%) 0.0
CALC LOAD(%) 32.9
COOLANT(°F) 113
ENG SPEED(RPM) 988
FUEL SYS 1 OPEN
FUEL SYS 2 N/A
IAT(°F) 95
IGN ADV(°) 26.0
LT FTRM1(%) 0.0
MAF(LB/M) 1.02
MIL STATUS Off
O2S11(V) 0.550
O2S12(V) 0.630
OBD2 STAT CA
ST FTRM11(%) 0.0
ST FTRM1(%) 0.0
VEH SPEED(MPH) 0

------------------------------

FRAME: 2 TM: 7.5

ABSLT TPS(%) 0.0
CALC LOAD(%) 32.9
COOLANT(°F) 113
ENG SPEED(RPM) 988
FUEL SYS 1 OPEN
FUEL SYS 2 N/A
IAT(°F) 95
IGN ADV(°) 26.0
LT FTRM1(%) 0.0
MAF(LB/M) 0.99
MIL STATUS Off
O2S11(V) 0.560
O2S12(V) 0.640
OBD2 STAT CA
ST FTRM11(%) 0.0
ST FTRM1(%) 0.0
VEH SPEED(MPH) 0

------------------------------

FRAME: 3 TM: 11.3

ABSLT TPS(%) 0.0
CALC LOAD(%) 34.1
COOLANT(°F) 113
ENG SPEED(RPM) 988
FUEL SYS 1 OPEN
FUEL SYS 2 N/A
IAT(°F) 95
IGN ADV(°) 26.0
LT FTRM1(%) 0.0
MAF(LB/M) 1.04
MIL STATUS Off
O2S11(V) 0.560
O2S12(V) 0.640
OBD2 STAT CA
ST FTRM11(%) 0.0
ST FTRM1(%) 0.0
VEH SPEED(MPH) 0

------------------------------

FRAME: 4 TM: 15.1

ABSLT TPS(%) 0.0
CALC LOAD(%) 32.6
COOLANT(°F) 115
ENG SPEED(RPM) 925
FUEL SYS 1 OPEN
FUEL SYS 2 N/A
IAT(°F) 95
IGN ADV(°) 26.0
LT FTRM1(%) 0.0
MAF(LB/M) 0.99
MIL STATUS Off
O2S11(V) 0.570
O2S12(V) 0.650
OBD2 STAT CA
ST FTRM11(%) 0.0
ST FTRM1(%) 0.0
VEH SPEED(MPH) 0

------------------------------

FRAME: 5 TM: 18.9

ABSLT TPS(%) 0.0
CALC LOAD(%) 34.5
COOLANT(°F) 115
ENG SPEED(RPM) 925
FUEL SYS 1 OPEN
FUEL SYS 2 N/A
IAT(°F) 95
IGN ADV(°) 26.0
LT FTRM1(%) 0.0
MAF(LB/M) 0.96
MIL STATUS Off
O2S11(V) 0.580
O2S12(V) 0.650
OBD2 STAT CA
ST FTRM11(%) 0.0
ST FTRM1(%) 0.0
VEH SPEED(MPH) 0

------------------------------

FRAME: 6 TM: 22.6

ABSLT TPS(%) 0.0
CALC LOAD(%) 34.1
COOLANT(°F) 115
ENG SPEED(RPM) 938
FUEL SYS 1 OPEN
FUEL SYS 2 N/A
IAT(°F) 95
IGN ADV(°) 26.0
LT FTRM1(%) 0.0
MAF(LB/M) 1.00
MIL STATUS Off
O2S11(V) 0.570
O2S12(V) 0.650
OBD2 STAT CA
ST FTRM11(%) 0.0
ST FTRM1(%) 0.0
VEH SPEED(MPH) 0

------------------------------

FRAME: 7 TM: 26.4

ABSLT TPS(%) 0.0
CALC LOAD(%) 32.6
COOLANT(°F) 115
ENG SPEED(RPM) 938
FUEL SYS 1 OPEN
FUEL SYS 2 N/A
IAT(°F) 95
IGN ADV(°) 26.0
LT FTRM1(%) 0.0
MAF(LB/M) 0.98
MIL STATUS Off
O2S11(V) 0.580
O2S12(V) 0.660
OBD2 STAT CA
ST FTRM11(%) 0.0
ST FTRM1(%) 0.0
VEH SPEED(MPH) 0

------------------------------

FRAME: 8 TM: 30.2

ABSLT TPS(%) 0.0
CALC LOAD(%) 34.5
COOLANT(°F) 117
ENG SPEED(RPM) 975
FUEL SYS 1 OPEN
FUEL SYS 2 N/A
IAT(°F) 97
IGN ADV(°) 25.0
LT FTRM1(%) 0.0
MAF(LB/M) 1.01
MIL STATUS Off
O2S11(V) 0.580
O2S12(V) 0.650
OBD2 STAT CA
ST FTRM11(%) 0.0
ST FTRM1(%) 0.0
VEH SPEED(MPH) 0

------------------------------

FRAME: 9 TM: 34.0

ABSLT TPS(%) 0.0
CALC LOAD(%) 34.5
COOLANT(°F) 117
ENG SPEED(RPM) 988
FUEL SYS 1 OPEN
FUEL SYS 2 N/A
IAT(°F) 97
IGN ADV(°) 25.0
LT FTRM1(%) 0.0
MAF(LB/M) 0.95
MIL STATUS Off
O2S11(V) 0.590
O2S12(V) 0.650
OBD2 STAT CA
ST FTRM11(%) 0.0
ST FTRM1(%) 0.0
VEH SPEED(MPH) 0

------------------------------

FRAME: 10 TM: 37.7

ABSLT TPS(%) 0.0
CALC LOAD(%) 34.5
COOLANT(°F) 117
ENG SPEED(RPM) 975
FUEL SYS 1 OPEN
FUEL SYS 2 N/A
IAT(°F) 97
IGN ADV(°) 25.0
LT FTRM1(%) 0.0
MAF(LB/M) 1.00
MIL STATUS Off
O2S11(V) 0.590
O2S12(V) 0.650
OBD2 STAT CA
ST FTRM11(%) 0.0
ST FTRM1(%) 0.0
VEH SPEED(MPH) 0

------------------------------

FRAME: 11 TM: 41.6

ABSLT TPS(%) 0.0
CALC LOAD(%) 34.1
COOLANT(°F) 117
ENG SPEED(RPM) 950
FUEL SYS 1 OPEN
FUEL SYS 2 N/A
IAT(°F) 99
IGN ADV(°) 25.0
LT FTRM1(%) 0.0
MAF(LB/M) 0.93
MIL STATUS Off
O2S11(V) 0.580
O2S12(V) 0.650
OBD2 STAT CA
ST FTRM11(%) 0.0
ST FTRM1(%) 0.0
VEH SPEED(MPH) 0

Okay. If this was taken when the vehicle was running poorly, I suspect you have a MAF sensor issue. If you look at where it says FUEL SYS 1 OPEN, this means it is running in open loop meaning it is ignoring all sensors except for the temp sensors and Mass air flow. As you can see, the short term fuel trims read 0 because it is ignoring them but your o2 sensor voltages are reading a little rich.

Can you run the engine long enough to get it hot and then send me the same numbers?

I am thinking you have an issue with the MAF but if you can send me the numbers after it says closed on that same line, I should be able to narrow this down a little more. Thanks

No Problem. I will do it tomorrow and send the numbers back to you. Thanks!

I ran it longer but not enough to fully warm up. Seemed to run worse the longer it ran. I am also low on gas so I do not want to run it until it is out of gas. Let me know if you can come to any further conclusions from the below data:

1996 OBDII/EOBD

I/M Monitors

Since DTCs Cleared

Misfire Monitor ok
Fuel System Mon ok
Comp Component ok
Catalyst Mon inc
Htd Catalyst n/a
Evap System Mon n/a
Sec Air System n/a
A/C Refrig Mon n/a
Oxygen Sens Mon inc
Oxygen Sens Htr ok
EGR/VVT Sys Mon inc

==============================

DTCs (Codes)

No codes found

==============================

Record Data

FRAME: -1 TM: -3.8

ABSLT TPS(%) 0.0
CALC LOAD(%) 33.7
COOLANT(°F) 131
ENG SPEED(RPM) 838
FUEL SYS 1 OPEN
FUEL SYS 2 N/A
IAT(°F) 104
IGN ADV(°) 20.0
LT FTRM1(%) 0.0
MAF(LB/M) 0.89
MIL STATUS Off
O2S11(V) 0.610
O2S12(V) 0.670
OBD2 STAT CA
ST FTRM11(%) 0.0
ST FTRM1(%) 0.0
VEH SPEED(MPH) 0

------------------------------

FRAME: 0 TM: 0.0

ABSLT TPS(%) 0.0
CALC LOAD(%) 34.1
COOLANT(°F) 131
ENG SPEED(RPM) 900
FUEL SYS 1 OPEN
FUEL SYS 2 N/A
IAT(°F) 104
IGN ADV(°) 20.0
LT FTRM1(%) 0.0
MAF(LB/M) 0.87
MIL STATUS Off
O2S11(V) 0.620
O2S12(V) 0.680
OBD2 STAT CA
ST FTRM11(%) 0.0
ST FTRM1(%) 0.0
VEH SPEED(MPH) 0

------------------------------

FRAME: 1 TM: 3.8

ABSLT TPS(%) 0.0
CALC LOAD(%) 32.9
COOLANT(°F) 131
ENG SPEED(RPM) 875
FUEL SYS 1 OPEN
FUEL SYS 2 N/A
IAT(°F) 106
IGN ADV(°) 20.0
LT FTRM1(%) 0.0
MAF(LB/M) 0.85
MIL STATUS Off
O2S11(V) 0.620
O2S12(V) 0.680
OBD2 STAT CA
ST FTRM11(%) 0.0
ST FTRM1(%) 0.0
VEH SPEED(MPH) 0

------------------------------

FRAME: 2 TM: 7.6

ABSLT TPS(%) 0.0
CALC LOAD(%) 32.6
COOLANT(°F) 131
ENG SPEED(RPM) 825
FUEL SYS 1 OPEN
FUEL SYS 2 N/A
IAT(°F) 106
IGN ADV(°) 20.0
LT FTRM1(%) 0.0
MAF(LB/M) 0.88
MIL STATUS Off
O2S11(V) 0.610
O2S12(V) 0.690
OBD2 STAT CA
ST FTRM11(%) 0.0
ST FTRM1(%) 0.0
VEH SPEED(MPH) 0

------------------------------

FRAME: 3 TM: 11.3

ABSLT TPS(%) 6.7
CALC LOAD(%) 37.7
COOLANT(°F) 131
ENG SPEED(RPM) 2063
FUEL SYS 1 OPEN
FUEL SYS 2 N/A
IAT(°F) 104
IGN ADV(°) 27.0
LT FTRM1(%) 0.0
MAF(LB/M) 1.29
MIL STATUS Off
O2S11(V) 0.490
O2S12(V) 0.590
OBD2 STAT CA
ST FTRM11(%) 0.0
ST FTRM1(%) 0.0
VEH SPEED(MPH) 0

------------------------------

FRAME: 4 TM: 15.1

ABSLT TPS(%) 0.0
CALC LOAD(%) 34.5
COOLANT(°F) 131
ENG SPEED(RPM) 825
FUEL SYS 1 OPEN
FUEL SYS 2 N/A
IAT(°F) 104
IGN ADV(°) 20.0
LT FTRM1(%) 0.0
MAF(LB/M) 1.01
MIL STATUS Off
O2S11(V) 0.620
O2S12(V) 0.630
OBD2 STAT CA
ST FTRM11(%) 0.0
ST FTRM1(%) 0.0
VEH SPEED(MPH) 0

------------------------------

FRAME: 5 TM: 18.9

ABSLT TPS(%) 0.0
CALC LOAD(%) 35.7
COOLANT(°F) 131
ENG SPEED(RPM) 775
FUEL SYS 1 OPEN
FUEL SYS 2 N/A
IAT(°F) 104
IGN ADV(°) 20.0
LT FTRM1(%) 0.0
MAF(LB/M) 0.89
MIL STATUS Off
O2S11(V) 0.620
O2S12(V) 0.700
OBD2 STAT CA
ST FTRM11(%) 0.0
ST FTRM1(%) 0.0
VEH SPEED(MPH) 0

------------------------------

FRAME: 6 TM: 22.7

ABSLT TPS(%) 0.0
CALC LOAD(%) 32.9
COOLANT(°F) 133
ENG SPEED(RPM) 863
FUEL SYS 1 OPEN
FUEL SYS 2 N/A
IAT(°F) 106
IGN ADV(°) 20.0
LT FTRM1(%) 0.0
MAF(LB/M) 0.87
MIL STATUS Off
O2S11(V) 0.620
O2S12(V) 0.690
OBD2 STAT CA
ST FTRM11(%) 0.0
ST FTRM1(%) 0.0
VEH SPEED(MPH) 0

------------------------------

FRAME: 7 TM: 26.4

ABSLT TPS(%) 0.0
CALC LOAD(%) 33.3
COOLANT(°F) 133
ENG SPEED(RPM) 900
FUEL SYS 1 OPEN
FUEL SYS 2 N/A
IAT(°F) 104
IGN ADV(°) 20.0
LT FTRM1(%) 0.0
MAF(LB/M) 0.87
MIL STATUS Off
O2S11(V) 0.630
O2S12(V) 0.710
OBD2 STAT CA
ST FTRM11(%) 0.0
ST FTRM1(%) 0.0
VEH SPEED(MPH) 0

------------------------------

FRAME: 8 TM: 30.2

ABSLT TPS(%) 0.0
CALC LOAD(%) 33.7
COOLANT(°F) 133
ENG SPEED(RPM) 875
FUEL SYS 1 OPEN
FUEL SYS 2 N/A
IAT(°F) 106
IGN ADV(°) 20.0
LT FTRM1(%) 0.0
MAF(LB/M) 0.84
MIL STATUS Off
O2S11(V) 0.640
O2S12(V) 0.710
OBD2 STAT CA
ST FTRM11(%) 0.0
ST FTRM1(%) 0.0
VEH SPEED(MPH) 0

------------------------------

FRAME: 9 TM: 34.0

ABSLT TPS(%) 0.0
CALC LOAD(%) 36.9
COOLANT(°F) 133
ENG SPEED(RPM) 1425
FUEL SYS 1 OPEN
FUEL SYS 2 N/A
IAT(°F) 106
IGN ADV(°) 24.0
LT FTRM1(%) 0.0
MAF(LB/M) 2.06
MIL STATUS Off
O2S11(V) 0.640
O2S12(V) 0.580
OBD2 STAT CA
ST FTRM11(%) 0.0
ST FTRM1(%) 0.0
VEH SPEED(MPH) 0

------------------------------

FRAME: 10 TM: 37.8

ABSLT TPS(%) 6.3
CALC LOAD(%) 22.4
COOLANT(°F) 133
ENG SPEED(RPM) 1725
FUEL SYS 1 OPEN
FUEL SYS 2 N/A
IAT(°F) 104
IGN ADV(°) 20.0
LT FTRM1(%) 0.0
MAF(LB/M) 1.18
MIL STATUS Off
O2S11(V) 0.580
O2S12(V) 0.600
OBD2 STAT CA
ST FTRM11(%) 0.0
ST FTRM1(%) 0.0
VEH SPEED(MPH) 0

------------------------------

FRAME: 11 TM: 41.5

ABSLT TPS(%) 0.0
CALC LOAD(%) 45.5
COOLANT(°F) 133
ENG SPEED(RPM) 813
FUEL SYS 1 OPEN
FUEL SYS 2 N/A
IAT(°F) 106
IGN ADV(°) 20.0
LT FTRM1(%) 0.0
MAF(LB/M) 0.91
MIL STATUS Off
O2S11(V) 0.640
O2S12(V) 0.700
OBD2 STAT CA
ST FTRM11(%) 0.0
ST FTRM1(%) 0.0
VEH SPEED(MPH) 0

------------------------------

FRAME: 12 TM: 45.3

ABSLT TPS(%) 0.0
CALC LOAD(%) 34.9
COOLANT(°F) 135
ENG SPEED(RPM) 875
FUEL SYS 1 OPEN
FUEL SYS 2 N/A
IAT(°F) 106
IGN ADV(°) 19.0
LT FTRM1(%) 0.0
MAF(LB/M) 0.91
MIL STATUS Off
O2S11(V) 0.650
O2S12(V) 0.720
OBD2 STAT CA
ST FTRM11(%) 0.0
ST FTRM1(%) 0.0
VEH SPEED(MPH) 0

------------------------------

FRAME: 13 TM: 49.1

ABSLT TPS(%) 0.0
CALC LOAD(%) 32.2
COOLANT(°F) 135
ENG SPEED(RPM) 863
FUEL SYS 1 OPEN
FUEL SYS 2 N/A
IAT(°F) 106
IGN ADV(°) 19.0
LT FTRM1(%) 0.0
MAF(LB/M) 0.86
MIL STATUS Off
O2S11(V) 0.640
O2S12(V) 0.710
OBD2 STAT CA
ST FTRM11(%) 0.0
ST FTRM1(%) 0.0
VEH SPEED(MPH) 0

Okay. We need to do a compression check before we go any further. Back to the basics for two reasons. First we need to make sure we have a good sound engine or this could get costly trying to replace parts that make sense. There is a good chance this is a valve issue. Second reason is, your volumetric efficiency is very low. Meaning the engine is not acting efficiently which is an indicator or a valve issue.

Here is a guide that shows how to do a compression check. Let me know what each cylinder comes back with. If these check out, I would suggest replacing the MAF sensor and then retesting.

https://www.2carpros.com/articles/how-to-test-engine-compression

Thank you for using 2CarPros.

So I ended up getting the MAF part before reading this reply. I installed it and the engine is running a lot smoother. However, there is a change in the problem. The engine is running smoothly, and the car drives smoothly, but after taking it for a test drive, there was excessive smoke coming out of the engine bay. It filled the cabin, and smelled somewhat like burned oil. The battery was also dead before I drove it, so I had to jump start it in order to start it up and take it for a test drive. Should I still do the compression check?

No. If the engine is running smoothly then I would think compression is okay. However, if there is that much smoke, you need to look for a leak. The old saying of where there is smoke there is fire, applies for oil on an engine as well. If it is on the exhaust it could catch on fire. If you can't locate one, then I would add a dye to the oil and see if you can locate it that way. Also, I would suggest just lifting the hood and letting the engine run until it gets hot and see if you can see where the smoke starts to come from.