Vehicle Inspection Emmisions FAIL

[Roybatty]

this morning....

Specifically, the hydrocarbon failed at 470 and the limit is 220 for low idle.

I was examining my WB at the time, it was showing slightly rich condition; hovering around 13.7 to low 14s.

Should I simply lean out the fuel delivery at idle and try it again? lmk what you all think. Thanks



PS the good news is my flex section actually passed as a catalytic converter. :Clap:

[Greg E]

Disable closed loop, tune manually via the MAF Comp tables.

[Greg E]

...or pour a gallon or two of isopropanol into your tank...

[mjannusch]

What do your fuel trims look like on each bank? Seem awfully rich, and at such low flow shouldn't need hardly any MAF comp. 13.7-14.0 isn't a little rich for idle, that's certainly enough to fail your emission test.

[Roybatty]

Greg, thanks for the input.


What do your fuel trims look like on each bank? Seem awfully rich, and at such low flow shouldn't need hardly any MAF comp. 13.7-14.0 isn't a little rich for idle, that's certainly enough to fail your emission test. I'll post up some logs ...try to get uploaded tonight.

[Roybatty]

Log attached. The battery voltage is substituted with wb data. There is some idle data scattered but the latest data is at the end of the file.

(https://docs.google.com/file/d/0B93z8rRgIUv6S0tVWkFzWmNMTDQ/edit?usp=sharing)https://docs.google.com/file/d/0B93z8rRgIUv6S0tVWkFzWmNMTDQ/edit?usp=sharing

This appears to be a recent development. Perhaps the change in formulation of gases from winter to warmer weather. Solution something as simple as cleaning the throttle body? I'll try leaning out fuel first/put it in open loop.

[mjannusch]

You probably need to retune your injector sizing and/or latencies because your low fuel trim is way out of spec. Fuel-trim Right Low is max'd out at 138%, though you say it is running rich - Do you have two functional O2 sensors? I'd log the fuel trim values for both banks (FTR and FTL) so we can see what's going on there - might identify a bad O2 sensor.

[wingnut]

PS the good news is my flex section actually passed as a catalytic converter. :Clap:

lol...so, does this mean you have ZERO cats?

[vroom4]

It means he has a noisy car I do believe.

[Roybatty]

You probably need to retune your injector sizing and/or latencies because your low fuel trim is way out of spec. Fuel-trim Right Low is max'd out at 138%, though you say it is running rich - Do you have two functional O2 sensors? I'd log the fuel trim values for both banks (FTR and FTL) so we can see what's going on there - might identify a bad O2 sensor.

I reloaded the log after cleaning it up.
https://docs.google.com/spreadsheet/ccc?key=0At3z8rRgIUv6dHJ0U2R0eHFjZGdKdTFvTDB4RXZVd UE#gid=0 (https://docs.google.com/spreadsheet/ccc?key=0At3z8rRgIUv6dHJ0U2R0eHFjZGdKdTFvTDB4RXZVd UE#gid=0)

I was baffled by this issue also. :confused: I was running with the NB 02s unplugged and used maftpro and WB to tune. This was because the NBs would always go rich around idle, fighting against my tune. Eventually I would get a cel for having NBs unplugged. Got tired of resetting the cel and plugged NBs in and this is the result. Stock injectors.

You may be correct, the NB o2s are lazy sometimes, but you can see in the log they are cycling(o2-f and o2-r)...not sure if the highs are what they should be. I wasn't aware of another way to log the o2s using MMCd.

So the WBs and NBs are not agreeing at low trims, but seem to be okay at mid and high trims. Again, there is a work around for getting past inspection as discussed above, but you are correct that something ain't right at low trims; perhaps should replace nb o2s?


Everyone says shes loud, but I have heard worse. Yep the precats are gutted too.:D

[Roybatty]

Passed the follow up inspection today. I unplugged NBO2s and adjusting fuel and settings to target stoich at idle. After running it a couple of days, I went back in to get inspected when the line wasn't too long.

I told them I got an O2 sensor replaced....the DMV operator started testing then said it wasn't looking good...OH NOEZZZZ....anyway my afr was hovering right around stoich...so not sure what was up with that...but my idle is low around 650...so he asked me to raise the rpm to 2500...then we went to just above 1000 rpms, asked me to hold it there...then it passed. So he said, its a trick to do to help clear it out...raise the rpms.

I understand some idles are high on their modded cars here for various reasons...but wanted to share what happened. I will work on cleaning out the TB and ISC...see if I can clean up my low idle.