LTFT's running lean.

[rockinace6]

ok guys im from sss.com i have an 03 sss with a small cam, lts, no cats, wires etc.... oil pump went out about a month and a half ago and we replaced it. the same day i was driving back to school and shot a p0131 code and i was told it was a bad o2. went to take it out and it had ceased in the bung. well had another bung welded about 8" behind that because thats the only place... so then the next day i shot a p1133 code (improper switching of bank 1 o2) and then that shot a p0171 (system lean bank 1). well i changed o2s from side to side, checked for vacuum leaks, checked for exhaust leaks, cleaned the injectors and swapped them from side to side. nothing. so yesterday i went and had the bank 1 bung relocated as far up as possible. that helped a lot.


first code cause my LTFT's to be..... bank 1 ranged from 19-25%
bank 2 ranged from 0-3%

so after the o2 bung was relocated YESTERDAY i was reading an average of 8-12.5% on BOTH banks. blackbear is my tuner and i cant figure it out. he said maf could be off, so i rotated that and cleaned it. same thing.


any advice??

[txarkitekt]

Bob, you ever try heating up the exhaust around the bung to see if it would expand and allow for the O2 to be removed from it's original position?

The placement of the O2s is crucial. The new O2 is placed too far downstream. Thats prolly the cause for your Bank 1 condition.

We have talked about the MAF and since there were no changes after you cleaned it, we can rule that out.

My mind keeps on going back to the placement of the O2. I say wrench the stuck one out, put a plug in the second hole (good place for a future Wideband), and put new O2 back upstream in the original location.

[RedHeartbeat]

+1 on taking some heat to it. Once you get it out run a thread chaser through it, should be an 18mm thread IIRC.

[rockinace6]

Bob, you ever try heating up the exhaust around the bung to see if it would expand and allow for the O2 to be removed from it's original position?

The placement of the O2s is crucial. The new O2 is placed too far downstream. Thats prolly the cause for your Bank 1 condition.

We have talked about the MAF and since there were no changes after you cleaned it, we can rule that out.

My mind keeps on going back to the placement of the O2. I say wrench the stuck one out, put a plug in the second hole (good place for a future Wideband), and put new O2 back upstream in the original location.

i already had the old one cut out like 2 weeks ago, i had ANOTHER bung welded yesterday and just capped the back one for a wideband. justin thinks it might be my maf or in my tune

[rockinace6]

+1 on taking some heat to it. Once you get it out run a thread chaser through it, should be an 18mm thread IIRC.

i took care of that a long time ago. i dont need to get anything out, its all been taken care of. ive already replaced o2's and thats not my problem.

[Duct_tape123]

Are you still trowing codes after the O2 relocation?

[eallanboggs]

I thought the same as others mentioned above. It's a lot easier to put a torch on a stuck O2 Sensor than it is to drill a hole and weld in a new bung. Have you checked your Freeze Frames? Try to duplicate the conditions recorded by the Freeze Frame data and then monitor the PIDs that effect fuel control. Have you tried to determine why only one bank is LEAN? Exhaust leaks can cause you to go lean as easily as intake leaks. Have you tried to watch your STFTs while you spray bank1(starter fluid, propane, brake kleen). Your STFTs will react quicker than your idle speed. Remember LEAN doesn't always mean too much air. The stioch ratio is 14.7:1. What if your problem is fuel starvation instead excess air because of the more common vacuum leak? You're LEAN either way.

[Duct_tape123]

I was helping him work on the truck and the plugs were black as night. The only things I can think of are exhaust leak(we fixed that issue), bad O2 sensor, or something in the tune that doesn't jive with what the sensors are reading.

[George C]

do you have an exhaust leak on driverside? say a broken header bolt? possibly a bad intake gasket on the driverside

[ChubbyBuddy]

Im chasing a similar problem....Im leaning toward an exhaust leak.Cold air is getting to the O2 sensor and the PCM is over correcting for the air leak