Jolly^Roger

Here's the story ...

Had a 232/232 112LSA cam installed along with new valvesprings, retainers, and pushrods. Previous mods include lid, k&n filter, long tube headers, offroad ypipe, and cat-back. Got it tuned. Dyno numbers were much lower than expected. SES light came on and eventually went away before I had a chance to scan it. So I picked up an LS6 intake (no EGR), ported throttle body and Magnaflow cat-back (used to be a custom catback w/ flowmaster muffer) and had them installed. Had the car retuned, dyno numbers were a bit better but still seem REALLY low (375rwhp, 357 rwtq). Picked it up and on the drive home SES came on again, scanned the car that night and I had TWO p0404's and one p0121. This is how my car sits right now. I've been waiting a few weeks to get some new fuel injectors installed (current ones are maxing out in the upper RPM's) and my SES light has been on the entire time. Tonight, just to checkup on things, I rescanned and pulled P0404, P0135, P0404, P0155.

I delete the codes. Go for a drive, 20 minutes city streets, no SES light. I get on the freeway. SES light comes on ~30 seconds (I counted) after I engaged 6th gear, 70mph @ 1900 RPM's. ... I counted this time because the first time the SES light came on I noticed it was immediately after getting into 6th gear .. And i've been driving the car in 5th cruising since then, except for tonight to see what would happen. I scanned the codes immediately after they showed up, and it shows P0404, P0153, P0404. 153 is not a typo .. 153 = slow response from 02 sensor bank x (froget which bank) sensor 1, and 155 = 02 sensor heater circuit failure bank x sensor 1.

I again pull off the road. Delete the codes. I begin driving again, city streets, never went into 5th or 6th gear. I get dinner. 30 minutes later I drive again, 10 minutes city streets, get on the freeway. Cruise at 70 mph in 5th for 15 minutes. I stick it in 6th and 30 seconds later SES light and p0404, p0404.

So what's the deal? Something is hinky and casuing two p0404 codes to be thrown at the same time. I realize that p0404 = EGR failure, however the tuner tuned it out during the 2nd tune and if the problem was in fact EGR, I would think it would come on a lot sooner and not be triggered by me doin 1900 rpms in 6th gear. I realize that 1900 rpms is outside the powerband of my car, but should that prevent me from cruising below that rpm range? And why the hell would it trigger 2 p0404 codes. Is it possible that the scanner I'm using is trying to read a code outside of its input range so it ends up reading 2? My two 02 sensors have probably seen better days and I will probably replace them soon but would they be resposible for so little power?

Thanks for your time. I apologize for the extremely long post but I don't think I could have explained my situation more clearly without doing so.

DaddySS

Sounds like 02 sensors are bad, and remember - EGR comes on at certain throttle position, RPM and speeds so that would explain the way it comes on but not why - if it's tuned out it shouldn't be checking. I would replace the sensors and have the tune checked. If you have autotap, what are your LTFTs, timing, etc. doing?

Steve Burger

iTrader: (33)

Check the O2 grounds at the back of the head. If they are not hooked up or broken you will get the O2 codes. I know from experience.

strokedls1

iTrader: (1)

The egr stuff is not deleted correctly. Your passenger side o2 is not working. That could cause a big loss in performance.

ktmrider

Check this out like Steve suggests. A truck guy had the same issue, the ground wire next to the cam sensor ( vertical mount bolt ) was not hooked up. Caused the exact same codes.