Check Engine w/ heavy exhaust smell

[1982GOBLUE]

Check engine light on....2000 Ford Explorer limited 5.0. Was on the other day went off after added one quart of oil. Back on in today.no visual but heavy exhaust smell. What can it be?

 

[8TZX]

The first step is to determine what code is causing the CEL to illuminate. If you don't have a code reader take it to most any auto parts store. They will plug in their OBD reader and tell you. Once you have the code report back to the forum.

 

[EB4X]

Get code and post here... other than strong smelling exhaust is there color to exhaust? ...bluish / white / black - dark ?
Stzx beat me to the punch...

 

[1982GOBLUE]

Get code and post here... other than strong smelling exhaust is there color to exhaust? ...bluish / white / black - dark ?
Stzx beat me to the punch...

no visual sign of exhaust just smell

 

[974X4BLACKSPORT]

If you have exhaust smell, you might have an exhaust leak. If you have an exhaust leak ahead of the O2 sensors, you will have unmetered oxygen being read by the O2 sensors, which would definitely throw a code.
Do you hear any exhaust "ticks" or "pfts" while accelerating?
Put a scanner on it and read what the code is first however.

 

[J_C]

Heavy exhaust smell where, in the cabin or outside the vehicle? If outside, is the exhaust any louder than previously?

If the smell is inside the vehicle, I would not drive it like this as you could get CO poisoning.

As others mentioned, get the OBD2 code(s) read with a scan tool, and check your oil again in case it is burning it fast and that's the source of the smell, though burning oil fast tends to make a lot of bluish white smoke.

 

[410Fortune]

 

[1982GOBLUE]

P1157 code bank 2 sensor 1. Upon completing an oil change I did a test drive and the catalytic converter right where the 02 sensor was started smoking. Can inpote

 

[RickOTR]

The code 1157 means that the downstream catalyst monitor sensor is not switching correctly! The most common cause of this code is a failed catalyst monitor oxygen sensor (after the catalytic converter), below is a list of possible causes, however pinpoint diagnosis of this code will require the use of a scan tool that can access and read live sensor data!

KOER DTCs P1137, P1138, P1157 and P1158 can only be retrieved during KOER Self-Test when the fuel control is ramped rich and lean and monitored for a voltage change on the downstream HO2S.

• DTC P0136, P1137 and P1138=HO2S-12
• DTC P0156, P1157 and P1158=HO2S-22

Possible causes:

• Wiring Concerns:
  • Pinched, shorted, and corroded wiring and pins
  • Crossed sensor wires
• Other Concerns:
  • Exhaust leaks
  • Contaminated or damaged sensor

 

[1982GOBLUE]

P1157 code bank 2 sensor 1. Upon completing an oil change I did a test drive and the catalytic converter right where the 02 sensor was started smoking. Can inpote

Can I potentially replace O2 sensor and live anot

The code 1157 means that the downstream catalyst monitor sensor is not switching correctly! The most common cause of this code is a failed catalyst monitor oxygen sensor (after the catalytic converter), below is a list of possible causes, however pinpoint diagnosis of this code will require the use of a scan tool that can access and read live sensor data!

KOER DTCs P1137, P1138, P1157 and P1158 can only be retrieved during KOER Self-Test when the fuel control is ramped rich and lean and monitored for a voltage change on the downstream HO2S.

• DTC P0136, P1137 and P1138=HO2S-12
• DTC P0156, P1157 and P1158=HO2S-22

Possible causes:

• Wiring Concerns:
  • Pinched, shorted, and corroded wiring and pins
  • Crossed sensor wires
• Other Concerns:
  • Exhaust leaks
  • Contaminated or damaged sensor

should I replace upstream sensor as well?

 

[C420sailor]

Downstream sensors measure cat efficiency. Upstream alter fuel trims.

I seem to remember reading about a failed upstream sensor triggering a downstream code, but yeah...if you’ve got a heavy gas smell, I would be skeptical that it’s a bad downstream

 

[RickOTR]

Can I potentially replace O2 sensor and live anot

should I replace upstream sensor as well?

Yes, replace both upstream and downstream sensors. o2 sensors should be replaced as preventive maintenance around 100k miles as they tend to get weak as they age.