All of my data logs show that I am not running lean. However, I am throwing the CEL daily. I'm using a PLX Devices SM-AFR and it is sending the narrowband signal to the stock ECU and the wideband signal to emanage ultimate. This has just started happening recently. I have made no modifications to the EFI system. When conditions are met, my stock ECU does run in closed loop which tells me that it is getting accurate data from the narrowband signal. Any ideas why I'm throwing this code?

 

Ok let's try to help...

Have you cleaned your MAF ? Have you changed it?
It could be faulty , or dirty.

Have you checked for vaccum leaks?

Have you checked for leaks after your MAF but before your TB?

Have you checked your spark plugs ?

Lean code , you didn't say what the code was , is the O2 sensor reading too much O2
in the exhaust , or a big difference between your pre-cat O2 and post-cat O2.

Are they both sending information back to your ECU? not just one sending info to the E-manage and the other to your ECU. The ECU compares the 2 readings to see if there is a problem.

The little silicone piece that connects your air intake to your TB may have a hole in it causing a leak after the MAF but before the TB.

Having a miss in one cyl can also cause it , doesn't have to be an all the time miss , but one that happens occasionally. check the gap , your boosted right? running at least 1 step colder plug? with a smaller than stock gap? platinum or iridium plugs?

Just a few things to look at.

 

first off, i appreciate the help. it's refreshing to see someone on here NOT trying to offer suggestions that are irrelevant to the post at hand.

k...to answer your questions, etc...

I am boosted. Have eManage Ultimate. Using a PLX Devices UEGO. I replaced the stock o2 sensor with the wideband a long long time ago. The way the PLX works is that it can send both WB and NB signals simultaneously. So, Ultimate gets the WB signal and stock ECU gets the NB signal.

This problem started right after I popped in a set of NGK Iridium one step colder plugs. The gaps were spot-on right out of the box. I indexed all of the plugs so that the spark faces the exhaust ports. Now, my stock ECU has been running in open loop when it should have been running in closed loop and thus fouling the plugs. After figuring out how to circumvent that with Ultimate and cleaning the fouled plugs, it still throws the CEL. I havent checked or cleaned the MAF since I dont believe its the cause.

All of my silicone couplings are Vibrant 4 ply and all brand new. So I am not leaning towards them either.

I have a spare set of NGK plugs and I'm going to swap them and see if it still throws the CEL.

thanks again for the help.

 

First suggestion , get rid of the iridiums , they are not good for boosted cars neither are platinums , stick with copper . the gap , if you have them gapped right out of the box ( .044 ?) the boost will blow out the spark. You should be running copper plugs one step colder with a narrower gap than stock.

Iridiums may be causing the problem with a miss when you boost .

Stock plugs call for a gap of either .031 in the manual or .032 on NGK and other manufactureers sites , I would try a .030 to start , if your problem gets a little better try .028 .

Keep me informed as to how it's going.