[bimmermans54]

Ok, I cut out my cats, and replaced it with straight pipe. I have all other cats and resonators out of the car. The Service engine light comes on, and every once and awhile this pic of an engine pops up on the dash. But I never go into limp mode. So, I keep reading about how all these people are putting DP's with no cats, or just removing the stock cats, and getting no CEL, what do I need to do, to get the lights off my dash? Do I angle the O2's? Do I build a little pipe extension so the O2 sits further away from the pipe? Please help!
PS
I also heard that if the wires are backwards it throws the CEL, is that even possible? To have the wires backwards?

[bimmermans54]

C'mon guys. All the other threads about the CEL from the DP's, everyone chimes in. Any help would be great!

[turbotko]

Well, read those posts then LOL. I would get some O2 sims......hack the wires so it's a direct connection to the factory harness, and see if the catalyst monitor stays away.

[bimmermans54]

The other posts dont give any help, or I would have never made a post. As for the 02 sims, where can I get those?

[verboten]

Here 'ya go...this is from the Ford guys , hard core Fox body & later 90's+ up OBD2 , Mustang drag racers forums. A lot of these guys use various brand name headers, X pipes, all with cat deletes (ONLY for off road use of course)...with the following circuit >>excellent results, and NO c-e-l s
PLEASE don't pm me , I didn't invent this...just found it and passing it along here. There is even a Co. Dallas Mustang that makes a "Plug-in-play" version of this circuit, but the plug in ends are spec: Ford and will not interconnect to the BMW lower O2 plug end design.
Radio Shack usually has these in their self serve drawers, if they are out just drive to the next outlet. I've tried this circuit out on the 3.0 Mazda6S with race headers, y-pipe, downpipe with good results.
Marty

[Lee Rambler]

cool, good find! thanks for posting. Pleae post your results as to how well it works for you...

[verboten]

Lee, the first time we did this mod was in 2005, on a new Mazda6S 3.0vvt with obd2 and a 5 speed (n/a car). The car dyno'd @ 210 FWHP with MSDS exhaust upgrades(168 stock) and still runs strong today with over 90K miles on it and never threw a C-E-L (exhaust related). On the Ford SVTs (24v duratec) that we mod...we just send the customer the Dallas Mustang units--with the same good results.
Keep all of the soldered joints well insulated...cause moisture can short the circuit out
Marty

[Lee Rambler]

cool, thanks. curious to see how well it works on the 335 too. I've been waiting to pull the trigger on the downpipes to see if anyone else runs into problems first...sorry guys, thought I'd let one of you be the guinea pig. hoping the OP tries the sim and reports back how well it worked...

[bimmermans54]

Well, I did it. It didnt work 100%. Now instead of it saying service engine, and having a picture of a yellow engine pop up and blink, it just says sevice engine... Also the obd2 just says that the rear 02s are inactive...

do downpipes void warranty?

[verboten]

...don't know if it matters but the Ford guys disconnect the battery during the "Circuit mod" and then re-connect it after the mod. The BMW obd2 seems to be a bit more sensitive to this trickery.
Marty