Contour Enthusiasts Group Archives Forums General Troubleshooting Gutted cats, then cel returns

A couple weeks ago I had my precats gutted and installed MIL Eliminators. The car ran with no cel for a couple days then the light came on for a couple days then went back off for a couple days. Now its been on for a week. I went and had it scanned (P 0430 Cat Effic. Below Threshold -Bank 2) Would that definitly be an O2 sensor? Which one is it? Should I replace both? Thanks, John

Try unplugging your MIL's and then pluging them in again.. Sometimes they dont snap in all the way. Having your CEL turn on and off sounds to me like one of your MILs isnt connected securily or is on its way out.

Jon, thanks for the reply but the eliminators where soldered into place and they are less than a month old.

It sounds to me like a bad O2 sensor. With these cars the CEL codes are not very accurate...it could be your cat or the O2...now it sounds like an O2. I was in the same situation as you a while ago. Now I just got the MSDS headders and am running the mil adapters. It was my cat gone bad....Change your O2 if you can;t find any good deals PM me I might be able to get you a brand new one for your car for about 60 bucks.....Just give me the model, engine and production date so i can reference it. I work in whole sale...so if you need my "assistance" let me know.

Roz

The upstream O2's you replaced were for A/F control. This is the down stream one.

Downstream sensors should be the ones that have the MIL elim's on them. If the elim's arent doing their job by keeping the voltage where it should be AND allowing the voltage to fluctuate a bit, then this sounds like the code you would get. Check the voltage on the output side of the elim's, though I forget right now what it should be, maybe someone else can help? I know in the archive's somewhere Terry answered this question for me when I fixed my cat's... -Nick