False/wrong O2 code set?
Thread Starter
Intermediate
Joined: Apr 2006
Posts: 27
Likes: 0
False/wrong O2 code set?
Hi,
I have a 94 LT1 with 190,000 miles on the clock and am trying to resolve a H63 and H64 code. The car runs rough down the road in both open and closed loops and sucks gas. Codes suggest car is running lean, but it runs very rich. Now for the question....The code is for the right front O2 sensor but I think it might actually be for the left front sensor???? I've replaced the right O2 sensor awhile back and still have the same codes and problems. When I was Seafoaming the engine I saw smoke rolling out of the very front left exhaust manifold shroud which tells me I have an exhaust leak which would or should be causing the left O2 sensor to set a code. I've heard of Ford F150's setting codes pointing to the wrong cylinder. Was wondering if this is possible here with my Vette or I just have a couple/several problems....lol
I also noticed today that when the codes set and the car goes into open loop my gas mileage goes up. From around 13 to15 mpg to 23 to 27 mpg at 70 mph. Still ran rough though.
Just purchased an Actron 9190 scanner today on Ebay and will know more about it later this next week. I did many searches and couldn't get much good information on this scanner or at least how it would work with the 94 Vette (OBD I with OBD II connector). I'll share my opinions once I get some hands on time.
Have a great day,
Bob
I have a 94 LT1 with 190,000 miles on the clock and am trying to resolve a H63 and H64 code. The car runs rough down the road in both open and closed loops and sucks gas. Codes suggest car is running lean, but it runs very rich. Now for the question....The code is for the right front O2 sensor but I think it might actually be for the left front sensor???? I've replaced the right O2 sensor awhile back and still have the same codes and problems. When I was Seafoaming the engine I saw smoke rolling out of the very front left exhaust manifold shroud which tells me I have an exhaust leak which would or should be causing the left O2 sensor to set a code. I've heard of Ford F150's setting codes pointing to the wrong cylinder. Was wondering if this is possible here with my Vette or I just have a couple/several problems....lol
I also noticed today that when the codes set and the car goes into open loop my gas mileage goes up. From around 13 to15 mpg to 23 to 27 mpg at 70 mph. Still ran rough though.
Just purchased an Actron 9190 scanner today on Ebay and will know more about it later this next week. I did many searches and couldn't get much good information on this scanner or at least how it would work with the 94 Vette (OBD I with OBD II connector). I'll share my opinions once I get some hands on time.
Have a great day,
Bob
Le Mans Master
Joined: Feb 2006
Posts: 8,753
Likes: 9
From: Louisiana
Sounds like you have an exhaust leak. Air entering the exhaust setting the lean code and the PCM is adding more fuel making the rich smell.
It could also be the AIR system dumping air into the exhaust stream in closed loop.
It could be a bad connection at the sensor, the wiring touching the exhaust and grounding, or a bad sensor.
Get the FSM (factory service manual) out and troubleshoot the codes for the correct answer. If you don't have a FSM, I would advise you to get one as they are worth the money if you are a DIY'er.
It could also be the AIR system dumping air into the exhaust stream in closed loop.
It could be a bad connection at the sensor, the wiring touching the exhaust and grounding, or a bad sensor.
Get the FSM (factory service manual) out and troubleshoot the codes for the correct answer. If you don't have a FSM, I would advise you to get one as they are worth the money if you are a DIY'er.
Thread Starter
Intermediate
Joined: Apr 2006
Posts: 27
Likes: 0
Replaced the right side O2 sensor and that fixed my gas mileage problem and the car now runs in the closed loop.
The manifold leak doesn't seem to be a problem.
Found the number eight sparkplug gap was mashed flat. (no gap) Don't know this happened, any ideas from anyone???????? Never had the intake open or any engine work ever done. Cars running great right now
The manifold leak doesn't seem to be a problem.
Found the number eight sparkplug gap was mashed flat. (no gap) Don't know this happened, any ideas from anyone???????? Never had the intake open or any engine work ever done. Cars running great right now
