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Hello, I have a weird lean rich condition that came out of left field. I was re tuning in closed loop since i upgraded to a c5z06 maf everything was going great then the wb and 02 sensors started acting weird. I replaced them all and check for a leak in the exhaust but nothing leaking. Returned table to stock to see if that was the issue but no change. Car is still going super rich .75-.82 and lean 1.15 -1.25 at different times when i start it no matter if i drastically add or remove fuel. No codes are throwing which made me think an exhaust leak. Any ideas would be appreciated.
My bad on the forum.
"No codes are throwing which made me think an exhaust leak".
Last time we saw that, the exh leak was the culprit.
Have a smoke tester?
What we use.
Are the headers aftermkt?
Last edited by Old Buzzard; Apr 9, 2023 at 09:00 AM.
P01 ls1 cam ported 853 heads headers, 3inch y pipe through borla exhaust. I checked for leaks and nothing was found. Could a clogged fuel filter cause this mine is custom from mechanic and reusable.
"Could a clogged fuel filter cause this mine is custom from mechanic and reusable".
Pull it off and take a look..
Have you checked fuel psi?
Time for a data log.
Here are the logs. You can see on the second one it goes super but it looks like everything is working right. Let me know if something sticks or it if its probably an exhaust leak.
It's definitely going lean, but it's not going rich.
When the WB is lean, the factory 02 sensors are 200-300mv(lean AF). After it dies, the WB goes to .50 lambda. When it restarts, it stays there but the factory 02 sensors are still dead lean. Eventually, the WB comes back to life and shows lean again.
If it was really going rich, when the WB is reading .50, the factory 02 sensors would be pegged at 900mv(rich AF). I always use the WB02 and the factory 02 sensors as a sanity check to verify if both are working properly.
I think when you restart it, the WB02 is warming back up and that's what it's showing.
The MAF is reading Hz, but it's not showing an lb/hr which I don't have a good answer for.
If you haven't yet, check your fuel pressure. I bet it's ****.
Last edited by LilJayV10; Apr 13, 2023 at 09:10 AM.
Correct wb going 1.23 Iean. I have an upgraded racetronics pump with reusable cartridge filter and an upgraded regulator outside the tank. It’s all a year old. My guess is the filter needs to be cleaned out. I’m going to pull the filter and clean it with carb cleaner, add seafoam and put new plugs in it to see what it does. If still the same issue my guess us an exhaust leak I can’t see and I will have my mechanic smoke test it.
Question. I have a fuel pressure Guage but can’t find a write up any where on how to remove the shrader valve and install it without damaging it. Any ideas?
Question. I have a fuel pressure Guage but can’t find a write up any where on how to remove the shrader valve and install it without damaging it. Any ideas?
The schrader will come right out with a core stem removal tool, should be able to get one at any hardware store or auto parts store. The fitting on the fuel rail is an AN fitting, and I used an AN to NPT adapter for my fuel pressure gauge sender.
A tool can be had at the local tire shop. Probably free.
Just ask for a tubeless tire stem, and a cap w/ the stem removal part on it.
My tire guy has handsful of them as new tires always get new stems.
Easier to find in the tool box.
Thanks for the reply I have decided to go with an aem electric fuel Guage instead as a lot of people at track and I have read stated it can be a fire hazard and the the one that goes under the hood should be used to check but not stay as the gas will eventually eat up the Gauge and cause a leak.
Thanks for the reply I have decided to go with an aem electric fuel Guage instead as a lot of people at track and I have read stated it can be a fire hazard and the the one that goes under the hood should be used to check but not stay as the gas will eventually eat up the Gauge and cause a leak.
A good choice, yeah I have an autometer, I find it very useful. And yeah definitely don't go old school with a fuel line up to the remote gauge. The sender is very easy to wire up anyway and a lot less hassle to run wiring to the cabin then a fuel line.
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Weird WB/02 sensor readings. 
