Originally Posted by Kyle2k (Post 6528737)

So - I did a header install about a week ago and I got around to doing some data logging for a tune. Bank 1 was running +14-18 and Bank 2 was all 0's for fuel trims.

For clarification I am running the old CF 2 piece Haltech intake and it has like 102+mm MAF sensor diameter area.

Is this just a sensor issue? Another idea that has been thrown around is an exhaust leak?

EDIT: Rear o2 sensors are removed and I have no FRONT o2 sensor DTCs.

Originally Posted by Kyle2k (Post 6528927)

I guess I'm just confused because the fuel trims on the one bank will NOT fluctuate from zero but at the same time I have no o2 DTCs so I have no clue if the sensor could also be fried/etc

Originally Posted by thahemp (Post 6528937)

I just logged mine. It runs between +1 and 0 on both banks stft and ltft. +18 seems like quite a bit of fuel being added for just headers. I have an intake and PTB. The intake (Fastlane Pipeline) supposedly runs lean according to Jannetty.

Does bank 2 just stick at 0? Or does it bounce around between 0 and +1?

Exhaust leak is a good place to start... like was said already. That's what I would be hoping for!

Originally Posted by The Stig (Post 6528928)

Any codes being thrown?

Originally Posted by thahemp (Post 6528945)

Snuck in before me. Maybe it's just going to take a bit for the code to be thrown. I have waited on codes for lots of miles before that I knew were supposed to be there. Do you have a multimeter? Or anything to monitor the voltage output from the bank 2 O2 sensor? I think it's supposed to fluctuate between 450 and 800mV as the computer trims things up.

Originally Posted by thahemp (Post 6529075)

Yep. Weird. Can you log O2 voltage? I can't remember if it is my sct or bluetooth module that shows the raw sensor voltages.

Just try loosening the headers and retightening them. It took me a bunch of tries to get everything happy at the manifold/midpipe flange when i did HF cats. It was a PITA to get it to seal.

Originally Posted by thahemp (Post 6529699)

I haven't looked those codes up, but that is an interesting graph. The one fluctuating rapidly looks like it should i think. The stft should bounce from lean to rich repeatedly. That's how they find stoich.

Check that bank 1 header!

Originally Posted by PQ (Post 6531421)

This stuff has always been confusing as hell to me. I wish I knew more about how the system worked and what this all means.

It would have to be a decent size leak I'd think. I've had leaks that never messed with the fuel trims and sensors. I've also had them that did.

Originally Posted by 04GOAT-11SS (Post 6535162)

The first 4 codes are all rear o2 sensor codes as you probably know. The P0154 is likely where your problem lies. The O2 sensor should be switching between 0-1v. A quick way to see if the 02 sensor is working is to wait for it to enter closed loop, create a small vacuum leak and make sure the voltage drops to around .1 volt momentarily. Then fix that leak, blip the throttle a few times and watch the o2 voltage. Should rise to nearly .9v. If they don't do that then it's time to start looking at the sensors, wiring etc. If it does that and it's just not switching enough (about 15 times during a 10 second time frame when holding the engine at 2k rpm) it's time to replace the sensor.

Originally Posted by Kyle2k (Post 6721243)

Well, it has been awhile but the car runs and I've got some of my other responsibilities out of my way, but I still haven't fixed the issue - I attached a new(different) datalog if anyone would mind taking a look - the diablo data viewer link is right here. I also included the O2 sensor voltages in the log...something is odd here and I think it is bank 2 more so than bank 1 that is throwing everything off.

http://www.diablosport.com/forum/vie...hp?f=31&t=2335

Originally Posted by litle88 (Post 6721359)

You have two suggestions that I'd go look into when you get a chance. Do the header check and make sure there's no leaks or soot around the connections or off the cylinder head. Also make sure the o2 sensor is tight.

If that doesn't work, swap sensors out and then get back to us bud.

Originally Posted by Badbubba (Post 6721326)

If you can, swap the sensors and see if the issue switches to the other bank.

Originally Posted by Kyle2k (Post 6721407)

Thanks for the advice guys, I have essentially done all the visual inspections for soot and I have found nothing around the heads - I will check to see if there is any around the sensors this weekend and if not I will just do the switch then.

For what it is worth it smells VERY rich on start up - occasionally bucks both after start up but then usually settles down with in 10-20 seconds and then also occasionally around town when I drive. However, when I get it back and turn it off it smells very lean. Other little tidbits - I am running one of the older two piece haltech intakes with the 102+mm MAF so bank 1 is reading high LTFT's because that's what I was told to expect (as opposed to some sort of exhaust leak) - the added headers probably isn't helping...

Originally Posted by axis (Post 6721607)

I'll trade you my yellowjacket for yours. I always wanted one of the older CF ones. Just couldn't pull the trigger for $600 though.

Originally Posted by Kyle2k (Post 6724753)

I might consider it, I'll pm you once I get this thing running decently - I have the car up at the moment and I noticed soot marks at the exhaust clamp it is about 6 inches behind the o2 port? Do you think that could throw it off if it is behind the sensor? Either ways I tightened it and am contemplating switching sides on the o2 sensors anyways

Originally Posted by Kyle2k (Post 6724753)

I might consider it, I'll pm you once I get this thing running decently - I have the car up at the moment and I noticed soot marks at the exhaust clamp it is about 6 inches behind the o2 port? Do you think that could throw it off if it is behind the sensor? Either ways I tightened it and am contemplating switching sides on the o2 sensors anyways

Originally Posted by thahemp (Post 6724898)

I don't. I'm fighting my band clamps too, but unless you're running open headers.. behind the front O2 isn't going to affect your fueling. That sensor voltage reading from bank 1 is wrong wrong. That is NOT how it is supposed to look. Move the sensors, let us know what happened.

Originally Posted by Kyle2k (Post 6724753)

I might consider it, I'll pm you once I get this thing running decently - I have the car up at the moment and I noticed soot marks at the exhaust clamp it is about 6 inches behind the o2 port? Do you think that could throw it off if it is behind the sensor? Either ways I tightened it and am contemplating switching sides on the o2 sensors anyways

Originally Posted by Kyle2k (Post 6725065)

By bank 1 do you mean bank 2? Bank 1 is at least the right range- the bank 2 voltage is just too narrow even though it looks more active. Here is the new log after swapping the o2 sensors from one side to the other. The fact that changing the sides on the sensors did nothing tells me the sensors probably aren't the issue though...

http://www.racetronix.biz/itemdesc.a...4T-24T&eq=&Tp= here is the wiring diagram for the extender.

The fact that the signal still oscillates though does that mean anything? If i just completely disconnected the sensor would it be any different?

Originally Posted by thahemp (Post 6727111)

And yes! Definitely I meant bank 2... these last few days have been pretty off for me :crazy:.