Can someone please explain to me why bank 2 is pulling 40% more fuel than bank 1? I swapped O2 sensors ( Denso ) with brand new ones and it still is pulling too much

 

Leaking Injector

 

Ok ill check I appreciate the reply. That sucks becuase they are brand new

 

Brand new? did these come from Ebay, Amazon, or some other Chinese selling source?

 

Nope. They were $800 from fuel injector development

 

You need to give some background information.

When did this problem start?

Is the car stock?

Why did you replace the injectors?

Are they stock injectors?

If not, has the tune been updated with the correct injector data?

 

Installed an LSA SC and have a base tune for it. Problem started after the install when I upgraded the ls1 fuel rail to the ls9 and new 60lb injectors. Tuner says the problem is mechanical. I changed plugs , O2 sensors and still have the issue. Did a smoke test and a leak down and I’ve got no leaks. Motor is far from stock but like I said I didn’t have the issue until I installed the sc. I can’t imagine new injectors and a new rail with 0 miles on it leaking but I haven’t checked that yet

 

Misfires leave raw O2 in the exhaust, which the O2 sensor interprets as running lean, which causes the PCM to reduce add fuel.
Is one of the headers primaries less hot than the others? Sometimes you can tell a difference just by licking your finger and tapping the header.
I went through this with my car over the spring/summer, and the root cause was a bad ignition wire harness.

 

Could my old MAF be the problem? The throttle body is 102mm and the MAF is only an old 80mm granetelli?

 

No. A faulty MAF is not going to effect one side of the engine only.

Do you have a log?

Key on, engine off, do the 02's show about the same mV?

 

I'm pretty sure you mean to to type, "which causes the PCM to add fuel".

I second the checking the temp of the header tubes.

 

I appreciate the replies. It’s so frustrating. Yes I have several logs and with the key on engine off they are pretty close to the same. I tried another smoke test , even sprayed around the passenger side hoping I’d hear the engine die but no leaks. Pulled the plugs and all 4 from that side are equally soaked so I find it hard to believe all 4 injectors are leaking but that’s my next step. When I upgraded to the 0411 pcm I also upgraded the harness instead of re-pinning my 98 to eliminate wiring issues but could that be an option?

 

Can you post a log? The side that is adding fuel, what is the 02 doing?

I have one idea, but curious about the 02 sensor before I mention it.

 

Sure thing. I have never uploaded a log file but I’ll try when I get home. The last log I saved the bar graph showed the bank 2 O2 sensor activity nearly top out in green almost the whole time which is where my screen shot showed the short term fuel for bank 2 at -39. I truly appreciate your help

 

Yep, thanks. Fixed.

 

heres my data log file attached. Hopefully someone smarter than me can help out. Thanks again

 

Humor me, do another log and add the rear 02 sensors to it.

 

Can’t do it. On my drivers side rear I’ve got my wide band sensor in the o2 slot and my passengers side rear was welded shut years ago

 

I understand that, but you can still log them.

In the log, I have never seen a stock 02 sensor read above 1v before, even running stupid rich.

I'd think if it was a mechanical issue, with that big of difference between bank to bank, it would be obvious.

There is literally a 90% difference between the sides. There's no way to know for sure which 02 sensor is correct.

If you have the WB02 in the driver side, what's it reading? IF the stock 02 sensor is telling the truth, it should be super lean.

 

When I have the KOEO it reads 22.5. I never paid close attention to the gauge while it was running but I remember seeing it around the 7-9 region running. I can fire it up and re-check the guage while its running. I know zero about tuning I was just going off the word of my tuner that it was mechanical. Its super frustrating pulling plugs and sensors every couple of starts. I pulled the passenger siude yesterday and they were wet and black and disgusting. Ill pull the drivers side tomorrow and put new ones it before I start it to get you that number.