LT4 Running Rich
Thread Starter
Burning Brakes
Joined: Mar 2008
Posts: 1,073
Likes: 8
From: Houston TX
LT4 Running Rich
My 1996 LT4 started throwing codes for the passenger side pre-cat O2 sensor last week so I replaced it.
The old one was pretty fouled up indicating that it is running rich. The car is still running rich and getting horrible gas mileage. Rich exhaust has a certain smell to it and this is definitely what mine smells like.
There don't appear to be and intake or exhaust leaks, so I am stumped...Any ideas?
The old one was pretty fouled up indicating that it is running rich. The car is still running rich and getting horrible gas mileage. Rich exhaust has a certain smell to it and this is definitely what mine smells like.
There don't appear to be and intake or exhaust leaks, so I am stumped...Any ideas?
Le Mans Master
Joined: Jan 2006
Posts: 5,621
Likes: 206
From: Orlando FL
Do a basic fuel pressure check.
Check the FPR, vacuum line.
Make sure the wiring and connectors connections (pins) to the O2 sensor are definitely good.
Get some scanner readings to see if the O2 sensor has any kind of proper voltage swing. Does the other side look OK?
I assume the engine temp digital read out is good or you would say so, this would influence the A/F a great deal.
If you run it that rich to long you will ruin the new O2 sensor. Did you install a Delco sensor?
Check the FPR, vacuum line.
Make sure the wiring and connectors connections (pins) to the O2 sensor are definitely good.
Get some scanner readings to see if the O2 sensor has any kind of proper voltage swing. Does the other side look OK?
I assume the engine temp digital read out is good or you would say so, this would influence the A/F a great deal.
If you run it that rich to long you will ruin the new O2 sensor. Did you install a Delco sensor?
Thread Starter
Burning Brakes
Joined: Mar 2008
Posts: 1,073
Likes: 8
From: Houston TX
Yes, a delco sensor was used. I drove it around and datalogged it a bit and the passenger side bank is running lean most of the time. The drivers side will read around .75 and the passenger is at .25
Thread Starter
Burning Brakes
Joined: Mar 2008
Posts: 1,073
Likes: 8
From: Houston TX
It turned out that despite replacing one of the O2 sensors, two more were fried. So I ended up replacing all four - no point in leaving just one old sensor in at that point...Now the car runs great, problem solved.
