2005 GXP Bonneville- PCM Tuning/performance mods

[kburnette92z]

Does anyone know of any well known reputable tuners, Or anything that will allow me to tune/re-program my 2005 Bonneville GXP OBDII PCM/Computer ..??

Reason being I did a few mods along with deleted/removed my CAT, and well... I have hit a small bump in the road naturally lol ! I'm mainly just trying to satisfy or remove my 2nd (rear) o2 sensor i.e. delete or zero out the tables for the o2's and possibly EGR, and smog pump tables, and also remove the top speed governor, change some shift points and firmness along with optimize it for what mods I have done to the good ole 4.6 Northstar V8 and of course to pull any additional HP -if any at all out of it .. I was told a good tune on this car can add a few numbers to my HP the wheels !? I have a CAT simulator that im using now and it gives good air and fuel readings, but my PCM is not satisfied with the o2 Heater signal it produces probably due to the fact the simulator is from my previous 1999 LS1 Firehawk Trans AM for one..!? But i used one on my 1999 SSEI after i deleted the cat in the second sensor location, and it works great no SES light or any issues prob due to the same year and PCM signal frequency similarities !? So i would assume my problem is the 2005 GXP's PCM parameters/signal frequency are either greater or out of range verses what the o2 simulator frequency range is, or can provide and function under, along with when and how frequently it monitors the temp of the sensor ...!? So either a proper resistance value or range so i can find and wire in a resistor, or a o2 simulator specifically for the car that will satisfy all the needs of the o2 readings to the PCM .. Im Also trying to locate a Throttle Body Spacer for it as well !?
- Any and all help/suggestions/Ideas/or additional mods that can be done are gratefully
appreciated !!

[sethjamesrimrodt]

Madtuner is about the only place that can tune our pcm, also our cars do not have a computer regulated top speed governor.


http://www.madtuner.com/index.php?page= ... &Itemid=26

[kburnette92z]

I figured as i have done a large amount of research and madtuner.com is about all i came up with as well ...

[01bonneSC]

Throttle body spacer does no good on point injection. They work with TBI and carbs but a waste on these cars.

[00Beast]

You're adding a few cubic inches to an already large intake. Worthless, especially the ones with the grooves in them that "swirl" the air. Believe me, the swirl lasts about an inch into the intake, and only affects a small portion of the overall flow anyways. Don't waste your money on one ever again.

[sethjamesrimrodt]

Our mass air flow sensors are hug!! Same part number as the one my dads 6.0 Silverado

[00Beast]

Which is funny, because people have been throwing them away because they think they need the truck MAF, but they are the same part...

[sethjamesrimrodt]

I know when I cleaned his I looked at it and was like hmmmm I'm going to check part numbers.. Same

[PhinkBigger]

Has anyone here actually gotten the Madtuner tune? $400 seems like an awful lot to lay out when the website has little details on what this actually will do!

[sethjamesrimrodt]

No I have emailed back and forth with him though. $400 really isn't that much,

[PhinkBigger]

No I have emailed back and forth with him though. $400 really isn't that much,

Yea I guess it depends what it does. What kind of improvements does the tune get you so far? If I remember right I read a thread somewhere that said he didn't have the PCM fully unlocked? If that even makes sense

[sethjamesrimrodt]

He claims he can do anything you want, I think he is claiming 10hp on a completely stock car.

[kburnette92z]

I will probably go with madtuner.com just due to the fact what else do i have to loose ..?? Hp is Hp and i will take all i can get, so Im going to get it mail order tuned eventually !! Also the MAF sensors the 2004-2005 GXP bonneville's have is the same as the 4.8-6.0 trucks along with ZO6 corvette etc.. I have an extra de-screened MAF, with the same part# if anyone is interested..


--* Also I found the perfect solution/Fix to removing your CAT and keeping the PCM's o2 sensor readings satisfied at the same time enabling you to keep your original o2 sensors !!
i.e.- No Service Engine Light, Better MPG, and a free flowing better sounding exhaust

[BigBonne]

Im so new here, and with a 05 gxp Bonneville.... What does this PCM tuning do? Does it help mpg, is it a tool or service?

[sethjamesrimrodt]

It will add a few HP and maybe gain a little milage but not much of either, it's hard to really gain much HP easily on a naturally aspirated engine without doing cams or porting, neither would be fun on a Northstar.

[repinS]

I was hoping Jake at Northstar Performance had done at least some light porting work when he owned the car and rebuilt half of it including the studs, but I've been told that only bone stock brand new heads went on :(

[ziggy145]

I will probably go with madtuner.com just due to the fact what else do i have to loose ..?? Hp is Hp and i will take all i can get, so Im going to get it mail order tuned eventually !! Also the MAF sensors the 2004-2005 GXP bonneville's have is the same as the 4.8-6.0 trucks along with ZO6 corvette etc.. I have an extra de-screened MAF, with the same part# if anyone is interested..


--* Also I found the perfect solution/Fix to removing your CAT and keeping the PCM's o2 sensor readings satisfied at the same time enabling you to keep your original o2 sensors !!
i.e.- No Service Engine Light, Better MPG, and a free flowing better sounding exhaust

kburnette92z, what did you do for the O2 sim fix you stated you used? I've attempted a O2 simulator 4049H from http://www.mopacautosupply.com/o2_simulators.html but I still throw a P0430. I'm curious what you did.

[CMNTMXR57]

I think you mean P0420. Catalyst low efficiency.

My guess is that the simms are not the correct resistance and/or faulty.

The other option is find someone to change the DTC type class code from a type A MIL commanding on, to a Type D or something, and never worry again.

However, I don't know that the minimal gain to remove the cats, if you're in an emissions tested area, is the best solution in the first place. But I am not one to preach as I am running catless on the GTO...