SUPERCHARGE

So listen guys, I own a 2002 GMC sierra 5.3L, so we're in the same boat when it comes down to tuning...

So... years ago, I installed a set of LT headers, big wide catalytic converters and a nice exhaust system and deleted rear O2's. Truck has never been tuned yet, always had more power than my firends equivalent truck, superior fuel mileage and always passed emissions with flying colors.

NOW... I went to do emissions, the SOB's use the OBD now??? Well f**k did I fail hard.

Now, I was close to buying EFI live and have my truck, and corvette tuned this year for the fun of it. But I'm guessing that those missing o2 sensors, regardless of what type of tune I give my truck will result in failure. Any suggestions here?

MMWS6

Buy the tuner and then drop me a PM... I'll help you out
I'd go HPTuners but I'm biased...lol

SUPERCHARGE

lol... yeah yeah, aren't we all, ford vs chevy, imports vs american, EFI vs HP. we just can't get along for one reason or another. I haven't tried either, but I understand EFI is less eye candy and more difficult, but is more precise and cheaper in the long run to tune multiple vehicles. And ok, I'll drop you a PM. I may very well go that route. Thanks!

Sleeper S10

iTrader: (13)

I had my computer tuned and harness made from the same shop.

O2's tunes out.

Was told in order to pass emissions they suggested they build my harness with the rear O2 wiring and that I run the sensors and not just for the visual part of it.

If I deleted the rear O2's and for me to pass emissions I needed the wiring there as it also set some signal off in favor to pass to the ECU/ PCM.

With rear O2's tuned out and no wiring\sensors hooked = no guarantee pass.
I don't have to worry and had this confirmed by several tuners.

Unless the tuning was possible at same time of the emissions test.
Now they are watching via camera.

MMWS6

You cannot perform any type of flash or "tune" at the time of testing. If you flash your PCM then monitor the "readiness state" of the DTC's you will see a few emission checks that are now "incomplete".... instant fail
You need a few cycles of operation for those to complete, then you can test it. Don't even waste your time if you have a dash light on, instant fail again

flame

iTrader: (13)

Here is all the info you need to get a pass
https://ls1tech.com/forums/pcm-diagn...or-issues.html

LETZRIDE

iTrader: (6)

Lol, I guess you missed the long emissions thread right below this, where every one of us has been bitching for the last few months.

There is a 50% fail rate of cars right now with the new testing. As much as I hate performance improvements, they just sent out a news letter in their performance catalog that has an entire article on the new testing and how many cars are failing


Be thankful that you need the OBD2 plug in test and not a 2-speed idle. ^^^^ This is all you need to do to pass; identify ALL emission DTC's and set them to level 3 with the SES light enable still checked. You have to make sure that you get all of them, because when you flash the car, sensors that aren't missing that would normally show ready will now fail and be unready as they haven't gone through the drive cycle. If you set all of the DTC's for all emission sensors to level 3 though its almost as it it throws them into a "loop", they always report back ready and no codes.

I on the other hand get to look forward to running my car on 3 cylinders this week to try and squeeze out a pass

MMWS6

I didn't want to post online and cause trouble on how to get around this test.... lol But, they are spot on there. #3 No Error Reported is the key to it, and as stated, do it to the right ones!

LETZRIDE

iTrader: (6)

gotta do it to all of them, once you flash the pcm it resets the good sensors to a non ready state lol.

Here, disclaimer...don't do the above to get around the test, that is highly illegal, and not supported by anyone here... We merely posted this info so that people have an understanding of how they could go around the test if it weren't illegal or you know, they were using the vehicle only for off-road purposes...but don't do so for legal car use....Also, don't use any mods that state they are for off-road use only...

^^there, I washed my hands of all legalities. If people choose to use this information to break the law, that's their problem... Given than GM can't figure out if a car has been touched by hp tuners without extensive work, the EPA can knock themselves out trying to figure that out to.

Baynut

iTrader: (5)

If one was to get a mail order tune and request for the above mentioned is it ok to keep the car like that for a long time... sorry if it seems dumb

LETZRIDE

iTrader: (6)

I wouldn't... When you put those codes to "no error" it basically throws them into a loop, so later on if something goes wrong, your car could be bucking and coughing all over the road and if the issue is related to that sensor, the car will never show a code to you and it will be difficult to diagnose.

Example, if you flip off all o2 sensors to the "no error" anytime you have a problem with your o2 sensors, no matter how bad the car runs, it won't throw a code until you change the tune back.

If you must get it done through a mail order tune, have them just put any sensorsyou dont have hooked up to no error, that way it doesnt matter (as there is no sensor hooked up to go bad lol).... Then you'll have to be mindful of completing drive cycles before you go in for a test.

You can always find someone with hp tuners to scan the car for you and tell you if all your sensors are ready. I can do this for you or anyone around Toronto for free if they need