Am failing emissions after 100 miles because of failing readiness codes and need to get these resolved. Any help would be appreciated.

 

Also, I have replaced the secondary O2 sensors in the last 2 weeks.

 

have you done the "proper" reset protocol?

this should do it..

Start engine, idle cold for approx. 2 min, 10 secs.

Accelerate to 20-30 MPH, Maintain steady speed for approx 3 min, 15 secs.

Accelerate to 40-60 MPH, Maintain steady speed for approx 15 mins.

Decelerate and come to a stop. Idle in gear* for approx 5 mins.

also..do NOT allow the engine speed over 3k rpm or you have to begin again. this is best done at 5-6 AM near a highway or open road for obvious reasons. it's not a traffic hour exercise, thats for sure. good luck. mine worked on the 2nd try.

 

you have a tune on it?

 

I will try this exact procedure. I have driven 100 miles with those speeds and kept the revs under 3k. But, I have not necessarily performed it in that exact order. Thanks.




And yes, I am running and EPL tune. No O2 code outs etc.. I may actually just have bad cats.

 

yes, there's something about the order of it that matters. good luck. barring any other issues, it will work.

 

I have an EPL tune as well and had to get updated with a catless tune for this issue. It seems that unless you have very high quality aftermarket cats the cats do not maintain temperature well. They heat up too much at WOT and cool down too much at idle. The monitor test never gets to run properly.

 

Usually all tuners shut off the secondary O2 sensory when you have a low restrictive cat or no cat, so you wouldn't have a cell.

 

EPL says you don't want to do this since this car is one of the few that actually uses the rears for AF correction. They edit something else to keep the O2's in play.

 

[QUOTE=sinKing;4064577]EPL says you don't want to do this since this car is one of the few that actually uses the rears for AF correction. They edit something else to keep the O2's in play.[/QUOTE


Tony at EPL did my first 18g tunes in the past > he asked what cats I was running then, they were 200 cell then and then I switched to 100 cell cats > So I asked him if the 100s would be OK now with his original tune.. he said He said it was ok because I think he said that the secondary sensor was off..
Also that's why others put a spacer in them to fool the ECU so they wouldn't get a cell..

 

I find it hard to believe that the secondary O2s schedule A/F. Especially considering people change to exhausts with lower cell cats without issues.


When I purchased the tune I communicated with Tony what exhaust I had. I doubt this is a tune issue. I hate to make this a tune issue until I know the facts. Tony runs a top notch business. I called him as soon as the issue surfaced to ask about the tune as a precautionary. I am not gonna jump on that band wagon yet. Sorry.

 

I am relaying information from EPL. He stated that they found they got better MPG when keeping the rear O2's. I wouldn't believe it either if it came from some chump on a forum.

Just to be clear, I am not suggesting the tune in a way to knock the tune because I am happy with the tune and EPL. I am just adding my experience and fix because you have the exact same symptoms I had.

 

No worries. I just wanted to be clear that I did not suspect the tube at this point.

 

Hopefully Tony will join in and clarify this..

 

I just went through an experiment that proved that the RR's on our cars do indeed impact long term fuel trims. I had the rear O2s plugged in to ECU but physically out of the exhaust stream in the engine compartment so I could use the rear bungs for AFR gauge sensors. Over a week's time the car slowly ran richer and richer until it was bogging and actually showed AFRs of 10-11 during idle.
I talked to my tuner about this (EPL) and they confirmed that the rear O2s being exposed to open air was causing this. Removing the battery cable for a few minutes reset the trims and idle values returned to 14.7.
I've since had additional bungs welded in and returned the rear O2s to the cat delete pipes and no more issues with LT fuel trims.