Chevy Silverado and GMC Sierra Forum banner
1 - 20 of 24 Posts

·
Registered
Joined
·
394 Posts
Discussion Starter · #1 ·
Hey, I loaded the preset 87 tune and was a bit surprised that it firmed up my shifts. Is that normal for the 87 tune?

I've never had an issue with my o2 sensors but many times now the code pops up as a low voltage code, is this something I need to worry about? I clear it and continue on driving but I'm questioning if the tune my be didn't take succefully.
 

·
Registered
2010 GMC Sierra WT RCSB
Joined
·
442 Posts
After you select the engine tune and modify any parameters, you should get the option to select a transmission tune. You may have selected "trans firm shift tune" or "trans hard shift tune". There is also an option to leave the trans tuning stock or modify the pressure/shift point/ torque management yourself.
I don't think the default 87 tune messes with air fuel ratio or O2 sensors but I could be wrong. What is the code you are getting?
 

·
Registered
Joined
·
394 Posts
Discussion Starter · #3 ·
I believe it was p0131. I just chose the basic 87 tune and it prompted me to axle ratio and that was it. I wasn't prompted to any trans option. Later I did modify tire size and that's all so far.
 

·
Registered
2002 RCSB Z71
Joined
·
158 Posts
My trans firmed up with the 87 tune also. It's about normal when driving normal but give it say half throttle and it's a firm shift. I think the code is just a coincidence. You could reload the stock tune, clear the code and see what happens....
 

·
Registered
Joined
·
2,719 Posts
After you select the engine tune and modify any parameters, you should get the option to select a transmission tune. You may have selected "trans firm shift tune" or "trans hard shift tune". There is also an option to leave the trans tuning stock or modify the pressure/shift point/ torque management yourself.
I don't think the default 87 tune messes with air fuel ratio or O2 sensors but I could be wrong. What is the code you are getting?
He has an older 2005 truck, there is no separate TCM/tranny module on his truck... He has a single PCM that controls both the engine and tranny....
 

·
Registered
Joined
·
394 Posts
Discussion Starter · #8 ·
I'm ok with the shift firmness as long as it doesn't break the tranny...lol. tranny was burnt pretty bad when I got the truck. I've nursed it as best I can by taking 2 liters/ adding 2 liters 2 times a year for the last 3 years. I am concerned about the rear driveshaft but I'll just get some spicers and be ready to replace. I like the way its shifting to be honest.
So what is that torque management setting for?? I'm looking to improve tq lower than what it's set for, or remove my drive by wire throttle delay. It's a bit much and hasn't improved with the basic tune.
 

·
Registered
2010 GMC Sierra WT RCSB
Joined
·
442 Posts
A firm shift should be better for the transmission life because the clutches are slipping less and making less heat. The shift firmness can be adjusted with transmission line pressure. Torque management is used to reduce engine power during shifts. You can disable or reduce it but this could be harmful to the transmission. I found another thread saying it is not recommended so haven't messed with it myself
 

·
Registered
Joined
·
394 Posts
Discussion Starter · #10 ·
A firm shift should be better for the transmission life because the clutches are slipping less and making less heat. The shift firmness can be adjusted with transmission line pressure. Torque management is used to reduce engine power during shifts. You can disable or reduce it but this could be harmful to the transmission. I found another thread saying it is not recommended so haven't messed with it myself
Thanks a lot for the advice! I'm gonna leave it well enough alone. I already got what I needed and everything I wanted. The real reason I got the tuner was because my truck was supposed to have 4.10 gears but the dealer that sold it to me either didn't test the 4wd or they put a rear diff with 3.73 gears and didn't verify. either way bad on them. I changed the front diff to 3.73on their buck to match the rear and at least was able to use the 4x4. Now I'm hoping to be able to use the 4wd auto this winter. Either a tune or go back to 4.10. But going back I need to buy the special tools and press so this is way better cause I'm making more power as my bonus
 

·
Registered
Joined
·
2,719 Posts
yeah, I would not disable the torque management, it's not good for the tranny to completely disable it.... On those older trucks, I don't completely disable it in my custom tuning either, I just reduce it so there's not as much, but there's still some there to help protect things... On newer trucks, there is no adjusting it, it's just an on or off setting, and I leave it on/stock setting, I don't disable it at all...
 

·
Registered
Joined
·
394 Posts
Discussion Starter · #14 ·
K so not so quick update, I don't think my o2 codes are related to my tune, how ever I the tune has exasperated the cel light because my mass air flow sensor is failing. Let me explain my thought process. Connecting the dots, I think the mass code and random misfire codes in the past are becoming prevalent. The truck itself is running rich noted by soot on the new tail pipe. The data I recorded some time ago from the mass I thought was normal until today reading other posts that the mass can fail by reading incorrect overages to the ecm translating to a rich condition picked up by my o2 sensors. Code 131 and 151 are popping up mainly when in open loop. And random miss fires when closed loop. My masses live data went from 102g/s to 221g/s in a split second at wot. She was making some power and running just fine even after the engine light came on, still pulling hard. But she does have a wobbly pop idle when in closed loop. She runs and drives impressively but I think if I change the mass all my problems go away. In my case, I'm sure it ain't the tune. Everything in the tune went as expected and my speedo was corrected 8 or 9km. The firm tranny shifts are consistent, the increase in power is there and even down low I can chirp the tires but she bogs from idle to 2500rpm and then we r gone! If I'm wrong, I'll still have a new mass sensor...lol
 

·
Registered
Joined
·
2,719 Posts
If you have misfires, that's a physical/mechanical problem.. a tune won't cause or fix misfires.. Check coils, spark plugs, plug wires, make sure plugs fully installed... make sure no cracked ceramics on any plugs, make sure plug wires are fully snapped on to plugs & coils (have had people before find that plug wires have slipped off, or even plugs have loosened up and come out)....

Also, get a can of CRC Mass Airflow Sensor Cleaner and clean the MAF sensor, and make sure it's re-installed facing the correct direction...

And if you end up getting a new MAF sensor, make sure you get a stock GM (ac delco / delphi) maf sensor that is for that year truck... Do NOT get an aftermarket MAF sensor like a jet or granatelli, etc etc... bad bad bad...
 

·
Registered
Joined
·
394 Posts
Discussion Starter · #16 ·
I don't get the misfire code all the time maybe 3 or 4 times in 3 years always while driving on the highway for about 5hrs. It's p0300 random but my son gets the p0300 more I think because he's trying to drive my truck like it's a manual. He likes the way the exaust pops on deceleration. Plugs and wires are a year old and I actually go through all the time making sure that aspect is good. I have tested the coil packs making sure they all have blue spark. The random misfire and mass codes have occurred prior to my tune but not on a consistent basis. On my old vehicle I had a mass issue and cleaning it made no difference so I'm not hopeful that cleaning this one will do anything either. I'm working alot of ot right now so I don't have alot of time unless something happens like being unable to drive the truck. For now I'm just keeping my scan tool handy and I'll go from there
 

·
Registered
Joined
·
394 Posts
Discussion Starter · #17 ·
Went for a 2hr drive and just got back. Got my first 1-2 tire squawk at 3500rpm. Granted I don't have sport tires. The tranny shifts have improved over the week and 3500 to 4000 1-2 are just a bit too hard, which is where i got the tires to break traction. 3000 is perfect 5g and up are very nice. Haven't got any codes even running many 3rd gear wots. Computer seems happier, I couldn't get the mass to step and trip the cel. I have a couple o2 sensors not reading, but I only have 3 sensors on my truck so not 4 or 5. Stf and ltf sensors are adding fuel but only going too low levels not having to minus fuel. Nothing abnormal at all. I'm noticing a difference in power and sound. Not talking exaust note wether I like it or not, no I'm noticing the tune. The way it sounds putting the power down, the mid rpm uphill pushes. It sounds and feels very... tuned. Much better than when first programed even.
 

·
Registered
Joined
·
2,719 Posts
Yeah... Every time you install a tune (or disconnect the battery), all of the learned items like idle, airflow, fueling/fuel trims, emissions readiness tests, transmission shifting adaptives, etc. all get erased/reset... It takes days/150-200+ miles to be put on for everything to be relearned by the PCM and settle in.

And you HAVE to have both FRONT o2 sensors installed and connected to their wiring harnesses, and working correctly... very important, as the two Front o2 sensors are the ones that control fueling/fuel trims.
 

·
Registered
Joined
·
394 Posts
Discussion Starter · #19 ·
As far as I can see my o2 sensors are working. Haven't got any codes in a couple days and haven't replaced anything. But I'm ready with my scanner if anything pops up. But damn I like the tune! Just waiting a bit cause I'm a bit unsure if hitting the 4wd auto button. That's what this is all for anyway.
 

·
Registered
Joined
·
394 Posts
Discussion Starter · #20 ·
Yeah... Every time you install a tune (or disconnect the battery), all of the learned items like idle, airflow, fueling/fuel trims, emissions readiness tests, transmission shifting adaptives, etc. all get erased/reset... It takes days/150-200+ miles to be put on for everything to be relearned by the PCM and settle in.

And you HAVE to have both FRONT o2 sensors installed and connected to their wiring harnesses, and working correctly... very important, as the two Fronto2 sensors are the ones that control fueling/fuel trims.
Really?? Everything gets lost? Just from disconnecting the battery?
 
1 - 20 of 24 Posts
Top