Having 02 Sensor Problems
Thread Starter
Drifting
Joined: Nov 2001
Posts: 1,684
Likes: 0
From: Jacksonville Florida
Having 02 Sensor Problems
As some of you might remember I was having 02 sensor problems last week. Two sets of codes on each of the four. All four had the code that relates to the sensor being slow to warm up. The front ones had actually stopped sniffing all together.
Turns out I had accidently run leaded gas in the car a few times, (gas station will be charged for repairs!).
New front sensors installed last Friday, car runs great (set new personal best at the track Friday night) - pulling great. Saturday morning start it up and she throws a code. I know it is not the front sensors as it is driving fine all the way to the Biltmore and back.
Hooked up the scanner today - both of the front (new) 02's are throwing the heater code again. No way is there still lead in the fuel. Codes are PO135 and PO155.
Question: Is there anything in the LS1 Edit tuning (we turned off the rear sensors because I was running without cats) that could be causing this?? What would you suggest I do next to get this corrected? Mods in signature.
Les
:cheers:
Turns out I had accidently run leaded gas in the car a few times, (gas station will be charged for repairs!).
New front sensors installed last Friday, car runs great (set new personal best at the track Friday night) - pulling great. Saturday morning start it up and she throws a code. I know it is not the front sensors as it is driving fine all the way to the Biltmore and back.
Hooked up the scanner today - both of the front (new) 02's are throwing the heater code again. No way is there still lead in the fuel. Codes are PO135 and PO155.
Question: Is there anything in the LS1 Edit tuning (we turned off the rear sensors because I was running without cats) that could be causing this?? What would you suggest I do next to get this corrected? Mods in signature.
Les
:cheers:
Racer
Joined: Apr 2001
Posts: 498
Likes: 0
From: Farmington Hills MI
Re: Having 02 Sensor Problems (ZO6Les)
This is a common problem when you run long tube headers. The front O2s are usually mounted further back than the factory position. The headers also don't carry as much heat and the 02s don't reach the proper temps. Another common cause is a leak in the exhaust system before the o2 sensors.
Good Luck
Good Luck
Thread Starter
Drifting
Joined: Nov 2001
Posts: 1,684
Likes: 0
From: Jacksonville Florida
Re: Having 02 Sensor Problems (jpas)
Thanks for the feedback. Some more details might help you tell me if you still think this is my problem.
The L/T's have been on for about 1,000 miles - no codes. Then I do the LS1Edit tuning (turning off the rear 02's since I don't run cats), no codes for about 500 more miles. Now I get the codes (probably due to the leaded gas). New 02's - no other changes. Drive car to track, race 5 times, drive car home - no codes. Start up the next day - CE comes on. Take it to mechanic fully warm, he resets the codes and they come back on instantly. REset againand they come on after about 10 minutes.
Question: If it is the positioning of the 02's why did it take so long for the original sensors to keck a code, and so little time for the second pair? Replacements are factory GM BTW.
Last Question: If indeed it is a positioning problem, what do you do to fix it?
Les
The L/T's have been on for about 1,000 miles - no codes. Then I do the LS1Edit tuning (turning off the rear 02's since I don't run cats), no codes for about 500 more miles. Now I get the codes (probably due to the leaded gas). New 02's - no other changes. Drive car to track, race 5 times, drive car home - no codes. Start up the next day - CE comes on. Take it to mechanic fully warm, he resets the codes and they come back on instantly. REset againand they come on after about 10 minutes.
Question: If it is the positioning of the 02's why did it take so long for the original sensors to keck a code, and so little time for the second pair? Replacements are factory GM BTW.
Last Question: If indeed it is a positioning problem, what do you do to fix it?
Les
Thread Starter
Drifting
Joined: Nov 2001
Posts: 1,684
Likes: 0
From: Jacksonville Florida
Re: Having 02 Sensor Problems (ZO6Les)
As you might remember I was having 02 sensor problems last week. two sets of codes on each of the four. All four had the code that relates to the sensor being slow to warm up. The front ones had actually stopped sniffing all together.
Turns out I had accidently run leaded gas in the car a few times.
New front sensors installed last Friday, car runs great (set new personal best at the track Friday night) - pulling great. Saturday morning start it up and she throws a code. I know it is not the front sensors as it is driving fine all the way to the Biltmore and back.
Hooked up the scanner today - both of the front (new) 02's are throwing the heater code again. No way is there still lead in the fuel.
Question: Is there anything in the LS1 Edit tuning (we turned off the rear sensors because I was running without cats) that could be causing this??
Les
Thread Starter
Drifting
Joined: Nov 2001
Posts: 1,684
Likes: 0
From: Jacksonville Florida
Re: Having 02 Sensor Problems (ZO6Les)
Well I feel kind of stupid but since two pretty good mechanics missed the obvious maybe I shouldn't feel so bad.
Since the saga of the sensors shutting off on the Z06 began the answer was fuel or ECM. Replacing the front sensors seemed to fix the CE codes for a short time.
I asked again today what is common to both front sensors - again answer was fuel or ECM. So we got it up on the lift and tested for voltage at the 02's - zip, zero. Check the fuses - you guessed it, blown fuse all this time! Why the ECM waited 100 miles or so after the new sensors to throw a code is a mystery.
So $184 later ($164 for 02's and $20 install, fuse and work today was free) the car is back running great, and no codes.
This is clearly a case of forgetting the simple stuff - lesson learned!
Thanks to all for your input and ideas!
Les
Instructor
Joined: Jul 2000
Posts: 150
Likes: 0
From: Seattle,WA
Re: Having 02 Sensor Problems (ZO6Les)
I think I have the same problem. What fuses are these that need to be checked to determine if they need to be replaced.
I got the Engine Check light with the codes:
10 PCM (4) Codes:
P0135 H C
P0141 C
P0155 HC
P0161 C
Have FLP Header system on my 1999 coupe
I got the Engine Check light with the codes:
10 PCM (4) Codes:
P0135 H C
P0141 C
P0155 HC
P0161 C
Have FLP Header system on my 1999 coupe
Thread Starter
Drifting
Joined: Nov 2001
Posts: 1,684
Likes: 0
From: Jacksonville Florida
Re: Having 02 Sensor Problems (ISLANDBOY2)
I am in England so I do not have the fuse info handy. On my car the fuse is labeled something like "02 Sensor" on the underneath side of the fuse box cover.
Hope this helps.
Les
Hope this helps.
Les
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Thread Starter
Drifting
Joined: Nov 2001
Posts: 1,684
Likes: 0
From: Jacksonville Florida
Re: Having 02 Sensor Problems (ISLANDBOY2)
Sounds like you have either:
1. Coated the 02's with a substance (Lead) and they are overheating, causing the fuse to blow (this is my theory on what happened to mine).
2. Have a short on the wires from the 02's back to the ECM, possibly getting too close to the headers?
My fuse has stayed well since replacement. Good Luck!
Les
1. Coated the 02's with a substance (Lead) and they are overheating, causing the fuse to blow (this is my theory on what happened to mine).
2. Have a short on the wires from the 02's back to the ECM, possibly getting too close to the headers?
My fuse has stayed well since replacement. Good Luck!
Les
Advanced
Joined: Aug 2006
Posts: 82
Likes: 0
Out of the blue (H/C installed for about 3 years no problems) my car starting throwing the P0135 code. Checked the fuse and it was blown! I hoping that clears the code once I get a replacement and if not at least I heading in the right direction,
I love the fourm! Thanks zo6les!
Oh and it is fuse 15 (15 Amp) in the engine compart fuse panel, it is right in the center between another 15 amp fuse and a relay.....you can't miss it
I love the fourm! Thanks zo6les!
Oh and it is fuse 15 (15 Amp) in the engine compart fuse panel, it is right in the center between another 15 amp fuse and a relay.....you can't miss it
