Side effects of a PCM tune

Sputnik312

Original poster
Member
Aug 9, 2012
38
Hey guys I have been looking into PCM tunes for awhile now but I really haven't seen any discussion about the disadvantages of one. It sounds like a good deal and would go along nicely with my cai but I'm just a little hesitant
Thanks
-Chris
 

rcam81

Member
Dec 3, 2011
209
Onsted, MI
Do it!!! I have had a tune since Oct '07 and haven't had any issues with it. It wakes our powertrains up.
 

Decembersend

Member
Dec 3, 2011
316
The reason you haven't read/seen any issue is because there are none. I mailed mine in and just waited i had a 3day turn around they're pretty quick about getting stuff out.
 

MacMan

Member
Mar 3, 2012
194
Sputnik312 said:
Cool! And unlike an intake I'll see noticeable power gains?

Yes, you will. Make sure to tell them what mod you did (CAI), and what you want from the tune (more power only?....more power & more MPG too??).....etc, etc.

I recommend getting rid of most of the Torque Management , and get trans shift firmness at 2.
 

Decembersend

Member
Dec 3, 2011
316
MacMan said:
Yes, you will. Make sure to tell them what mod you did (CAI), and what you want from the tune (more power only?....more power & more MPG too??).....etc, etc.

I recommend getting rid of most of the Torque Management , and get trans shift firmness at 2.

:iagree:
 

CaptainXL

Member
Dec 4, 2011
2,445
rcam81 said:
Do it!!! I have had a tune since Oct '07 and haven't had any issues with it. It wakes our powertrains up.

Really? With 87 octane gas? I want to keep using 87 but PCM4less says to use premium. The reason I am not getting a tune. Correct me if I am wrong.
 

Boricua SS

Member
Nov 20, 2011
3,080
Ohio
the tune is by far the best "bang for your buck" mod you'll ever do on your truck... there are disadvantages out there, and as someone said, you just don't hear about them... remember, you're altering factory things, taking out torque management, changing pressures in your tranny lines, altering fuel and spark ratios, etc... so as with any mod that you do across the spectrum, possibilities are out there for things to go wrong, but the failure rate from a tune is pretty much slim to none.. just all depends on how you drive your vehicle and how aggressive you get with the tune.. beat the piss out of your ride, it will break... treat her right, and she will last a good while...

IMO, pros are increased MPG's, slight HP increase, no more lagging throttle response, firmer shift points in the tranny, and just an overall better driving experience in the truck and actually how things should've been from the factory...

cons, there really aren't any... some have had issues with the security relearn and the CASE relearn, some thought the tune was a waste of their money, meaning they didn't feel a difference in shift firmness or something along those lines.. but for the better part of the population on GMTN, TBSSowners, and the OS, the pcmforless tune is the way to go, and none of us have looked back...
 

Lima Tango

Member
Dec 4, 2011
242
I had it done and definitely wouldn't do it again. My biggest complaint is the 1-2 shift is inconsistent and varies between soft and very harsh and jerky now, I cringe when I can feel a bad one coming. I have gotten word from a few others that have the same 1-2 issue, both with shift level 1 or 2, so be warned. That alone makes me regret it because its unpleasant in general but I am concerned for the life of my transmission as well. Otherwise, there is a nice boost to drivability, both in terms of power and throttle response. I did not get any MPG improvement. I can say my shift issue improved somewhat when I fully drained and replaced with DexVI, so I would definitely recommend you put that on your to-do list if you have DEXIII.
 

MacMan

Member
Mar 3, 2012
194
CaptainXL said:
Really? With 87 octane gas? I want to keep using 87 but PCM4less says to use premium......Correct me if I am wrong.

I have never heard that, nor did PCM4L ever tell me that when I got mine done. 87 octane only in my TB.
 

Lima Tango

Member
Dec 4, 2011
242
MacMan said:
I have never heard that, nor did PCM4L ever tell me that when I got mine done. 87 octane only in my TB.

You can select what octane you want to run when you order the tune: when I ordered I went with 87 octane. They advised at the time that you could get 2-3hp gains by increasing the octane, which was not worth it to me.
 

MacMan

Member
Mar 3, 2012
194
Lima Tango said:
You can select what octane you want to run when you order the tune: when I ordered I went with 87 octane. They advised at the time that you could get 2-3hp gains by increasing the octane, which was not worth it to me.

I understand that. What I meant was, PCM4L did offer the "premium gas" upgrade, but never said ALL the tunes required it.

I agree....2-3 HP is not ever going to be noticeable.
 

03envoy

Member
Dec 25, 2011
537
Only side effect i have is more gas money cause i cant keep my foot off the gas I have to much fun! lol I got shift firmness 2 and love the "stiff" shifts and love the harsh shift when you get on it:raspberry:
 

marshall@pcm

Member
Dec 6, 2011
260
Lima Tango said:
I had it done and definitely wouldn't do it again. My biggest complaint is the 1-2 shift is inconsistent and varies between soft and very harsh and jerky now, I cringe when I can feel a bad one coming. I have gotten word from a few others that have the same 1-2 issue, both with shift level 1 or 2, so be warned. That alone makes me regret it because its unpleasant in general but I am concerned for the life of my transmission as well. Otherwise, there is a nice boost to drivability, both in terms of power and throttle response. I did not get any MPG improvement. I can say my shift issue improved somewhat when I fully drained and replaced with DexVI, so I would definitely recommend you put that on your to-do list if you have DEXIII.


I'm not familiar with your situation, so maybe you've already spoken with Kelly, but normally would would happen is you can always send it back in an let us change the shift firmness back to stock. Then you'd be totally happy with it. :smile:
 

Lima Tango

Member
Dec 4, 2011
242
marshall@pcm said:
I'm not familiar with your situation, so maybe you've already spoken with Kelly, but normally would would happen is you can always send it back in an let us change the shift firmness back to stock. Then you'd be totally happy with it. :smile:

Kelly did immediately offer to change the shift back to stock, but I would have had to pay for shipping and be without my PCM for a week or more for roundtrip shipping. Thats not something I could do, which is why I did the loaner program in the first place. That's the perils of mailorder tuning, I suppose.
 

TB360

Member
Dec 29, 2011
169
I did the following:

- PCM Tune #3
- K&N 57 Series CAI
- 91 Octane

You would feel the difference and a little roar.

I would not do less than #3 since #3 doesn't feel too much so I would think #2 would feel like stock.

I always put premium since my TB is not my DD. If you want significant changes feel, you would MAXIMIZE all the options available, otherwise, you wouldn't feel that much difference and NOT worth doing it. Side effects? My foot seem heavier for wanting to hear the roar and feel the tune quicker response.

Been runnning this setup for a while now and still happy.
 

HARDTRAILZ

Moderator
Nov 18, 2011
49,665
Possibly the best mod i did to my truck was the pcmforless and I have done a lot of mods.
 

rodehawg

Member
Jul 19, 2012
13
Let's suppose a tune is ordered from PCM4L and it is stated the customer would like to generally use 91 octane rated fuel. After the tune is applied/installed, if the customer runs a lower octane rated fuel, will the PCM still be able to pull timing and such on the fly enogh to compensate, or would it be a problem? Or does it depend yet on optimized for 93 but run all the way down to 87 is a problem but 91 to 87, or 93 to 89 not a problem etc.?

Supposedly the stock PCM can run the motor safely on lower octane but pulls timing and what not to do so, which reduces maximum available power from the engine a bit. My 2007 SS reccommends 91 octane but says you can go down to 87 safely if the vehicle is in proper working order. What happens after a tune (from PCM4L or otherwise)?

From the owner's manual:

If your vehicle has the 6.0L V8 engine
(VIN Code H), use premium unleaded gasoline
with a posted octane rating of 91 or higher. You
may also use regular unleaded gasoline rated at
87 octane or higher, but your vehicle’s acceleration
may be slightly reduced, and you may notice a
slight audible knocking noise, commonly referred to
as spark knock. If the octane is less than 87, you
may notice a heavy knocking noise when you drive.
If this occurs, use a gasoline rated at 87 octane or
higher as soon as possible. Otherwise, you might
damage your engine. If you are using gasoline
rated at 87 octane or higher and you hear heavy
knocking, your engine needs service.
 

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