Custom EFI Live tune;failed emissions big time
04-07-2010, 12:20 PM
#1
Staging Lane
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Custom EFI Live tune;failed emissions big time 2002 Trans Am with 3" QTP long tubes, SLP lid, full customer 3" stainless exhaust and Borla exhaust. 2 years ago I paid a shop to do an EFI live dyno tune. The car runs great, 28 mpg on the highway if I don't have the A/C on. Fresh oil in the car, plugs are TR6's with about 2K miles on them. HC GPM values double acceptable, CO GPM values, 30% over high limit, NOx GPM more than double high limit.
I have the EFI Live V1 scan tool, don't have the tune tool or the chops to use it. If I buy the tune tool will I be able to see/save the custom one the shop put on it? Can I flip it back to the stock tune to see if it will pass emissions that way> (I know, for a guy from Colorado...I sure ask alot of questions) Advice welcomed.
I have the EFI Live V1 scan tool, don't have the tune tool or the chops to use it. If I buy the tune tool will I be able to see/save the custom one the shop put on it? Can I flip it back to the stock tune to see if it will pass emissions that way> (I know, for a guy from Colorado...I sure ask alot of questions) Advice welcomed.
04-07-2010, 12:48 PM
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Staging Lane
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Hanksville just put on new Magnaflo metal substrate high performance cats last June. I certainly hope not, they were >$150 each. Also, the chick driving the car at the inspection put it in 4th gear and ran it at very low rpm, so the car was lugging when she accelerated. While I appreciate her not beating on my car, I suspect her approach of accelerating from 1200 RPMs didn't help my cause.
04-07-2010, 01:08 PM
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Lugging it probably did not help the test.
Usually bumping up Idle RPM takes care of some of the problems you described. If you passed Idle, but failed at cruise...its hard to think of tune wise what could be contributing to it.
Normally with a stock cam you will pass with flying colors. If you still have the narrowbands functioning and are in closed-loop, then you start to suspect the cats. I guess if you are open-loop and were overly rich, then the tune might be suspect.
If all else fails, then I would just retake the test. A stock cam usually passes quite easily out here.
Good luck..
Usually bumping up Idle RPM takes care of some of the problems you described. If you passed Idle, but failed at cruise...its hard to think of tune wise what could be contributing to it.
Normally with a stock cam you will pass with flying colors. If you still have the narrowbands functioning and are in closed-loop, then you start to suspect the cats. I guess if you are open-loop and were overly rich, then the tune might be suspect.
If all else fails, then I would just retake the test. A stock cam usually passes quite easily out here.
Good luck..
04-07-2010, 01:48 PM
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High flow cats are less effective than stockers.
But high CO and HC and NOx all at once, I imagine has
to do with the headers and slow sensor switching (maybe
some transport delay, but more likely just cold) making
the mixture overtravel as it seeks cross-counts and
spending too much time in over-lean and over-rich,
too little near center.
Of course an injector imbalance can also produce this
kind of soup even at dead center (in sum) with the
lean holes producing the NOx and the rich ones, CO.
But high CO and HC and NOx all at once, I imagine has
to do with the headers and slow sensor switching (maybe
some transport delay, but more likely just cold) making
the mixture overtravel as it seeks cross-counts and
spending too much time in over-lean and over-rich,
too little near center.
Of course an injector imbalance can also produce this
kind of soup even at dead center (in sum) with the
lean holes producing the NOx and the rich ones, CO.
04-07-2010, 02:00 PM
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Staging Lane
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Thanks for the info Gents. (Holy cats there are some sharp folks out there) Hank tells me he has had very good luck with the metal substrate Magnaflo cats passing emissions (with flying colors). I did take the car out, bring it up to temp knowing the car needs to be hot. I let it idle for the 20 minute wait to get it into the test. They turn it off, sits for 20 minutes...then fire up the test. So much for being hot. Hank also said "If the tune is rich it will kill the cats". His suggested approach is to get on a wideband 02, check the AFR and go from there. If that checks OK, we will look to replace the cats and retest.
PS - Can scan the emissions graph if that is helpful to the tuning guru's.
PS - Can scan the emissions graph if that is helpful to the tuning guru's.
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04-07-2010, 03:20 PM
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Not clear on what you mean by read the PCM Mike. With EFI Live V1 scan I can select PIDS, drive the car and record the events of the selected PIDS while driving. I've only done it a couple of times, so I'm a novice, but can navigate the tool and capture data with the EFI Live cable, box and my Thinkpad.
04-07-2010, 04:09 PM
#10
You asked:
You don't need to upgrade to scan&tune to do this.
You can download the tune from the PCM, save it and make changes to the tune,
you just can't reflash the PCM with the new tune unless you upgrade to scan&tune.
Basically you have full use of the software with scan only,
the only thing scan only can't do is flash the PCM.
You can download the tune from the PCM, save it and make changes to the tune,
you just can't reflash the PCM with the new tune unless you upgrade to scan&tune.
Basically you have full use of the software with scan only,
the only thing scan only can't do is flash the PCM.
04-09-2010, 08:35 AM
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Right, which is what makes me say it's either a "static"
imbalance (various cylinders rich and lean simultaneously)
or a "dynamic" overtravel in the closed loop dragging the
mixture back & forth in quick time with the sniffer showing
a composite.
If you had a scan tool and locked idle AFR at stoich, you
could see whether this produces the same "soup" or maybe
only one flavor. The latter indicating that it's a loop
problem; the former, fuel delivery imbalance.
imbalance (various cylinders rich and lean simultaneously)
or a "dynamic" overtravel in the closed loop dragging the
mixture back & forth in quick time with the sniffer showing
a composite.
If you had a scan tool and locked idle AFR at stoich, you
could see whether this produces the same "soup" or maybe
only one flavor. The latter indicating that it's a loop
problem; the former, fuel delivery imbalance.
04-12-2010, 03:02 PM
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Gents, back from a long weekend vacation and thank you for weighing in:
Schwanke: I'm running TR6's as that what was recommended by the shop that did the tune. I get the sense you may think they are too cold for a daily driver with stock heads and cam.
JimmyBlue, when you talk about using the scan tool to lock the air fuel ratio at stoich, are you suggesting this can be done with EFI Live V1 scan or are you talking about a commercial scan unit?. I've only scratched the surface of my EFI Live function.
Joecar: Stock MAF with Bosch O2 sensors replaced last May in banks 1 & 2 sensor 1 position, O2 sims in both banks sensor 2 position
Schwanke: I'm running TR6's as that what was recommended by the shop that did the tune. I get the sense you may think they are too cold for a daily driver with stock heads and cam.
JimmyBlue, when you talk about using the scan tool to lock the air fuel ratio at stoich, are you suggesting this can be done with EFI Live V1 scan or are you talking about a commercial scan unit?. I've only scratched the surface of my EFI Live function.
Joecar: Stock MAF with Bosch O2 sensors replaced last May in banks 1 & 2 sensor 1 position, O2 sims in both banks sensor 2 position
Last edited by ajsfirehawk; 04-12-2010 at 03:35 PM.
04-12-2010, 09:54 PM
#17
TECH Senior Member
Log your front O2 voltages using a scantool... if they are switching properly and if the LTFT's are reasonable values, then the cats should be converting the 3 gases (HC/CO/NOx) so you shouldn't fail the the sniffer...
do what Jimmy suggested using the EFILive scantool you have...
Log these pids:
TP
RPM
AFR
LONGFT1
LONGFT2
HO2S11
HO2S21
MAP
MAF
DYNAIR
DYNCYLAIR
ECT
IAT
SPARKADV
KR
VSS
do what Jimmy suggested using the EFILive scantool you have...
Log these pids:
TP
RPM
AFR
LONGFT1
LONGFT2
HO2S11
HO2S21
MAP
MAF
DYNAIR
DYNCYLAIR
ECT
IAT
SPARKADV
KR
VSS
Last edited by joecar; 04-12-2010 at 10:01 PM.
04-13-2010, 09:16 PM
#19
Staging Lane
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Logged data Created a log with the PIDs requested by Joecar. Just cruising to a place I could open it up a bit for the first 4.5 minutes. Then was able to jump on it a bit. Thanks again for reviewing the data.
Last edited by ajsfirehawk; 04-13-2010 at 09:37 PM.