2008 Vmax Driveability Like A Badly Setup Quadrajet

Spurshot · January 4, 2009

I had my GMT900 08 Crewcab VMax for about 2 weeks now and I am disappointed with some things about it.

One is the driveability really is crappy. I don't know if it's just my truck or all of the VMax trucks. But, the idle, off idle, and low throttle response is as bad as an old carbureted engine with a plugged low speed circuit. The engine idles rough and transitions poorly and falls flat when you step on it.

Any input from you other VMax owners would be appreciated. Is this typical of all these new VMax engines? If so, are there some aftermarket cures? (Supertune, etc)

VMax2007 · January 4, 2009

I had my GMT900 08 Crewcab VMax for about 2 weeks now and I am disappointed with some things about it.

One is the driveability really is crappy. I don't know if it's just my truck or all of the VMax trucks. But, the idle, off idle, and low throttle response is as bad as an old carbureted engine with a plugged low speed circuit. The engine idles rough and transitions poorly and falls flat when you step on it.

Any input from you other VMax owners would be appreciated. Is this typical of all these new VMax engines? If so, are there some aftermarket cures? (Supertune, etc)

Idle issues are not typical, but yes, driveability sucks thanks to GM's ultra-conservative tuning.

Simple (and best) solution:

www.blackbearperformance.com

Do a seach for Blackbear or Black Bear on here and you will have hours upon hours of reading.

Spurshot · January 4, 2009

Jeff,

I see on some other threads that you had stated you had the Nelson tune. Would you recommend BB over Nelson?

VMax2007 · January 4, 2009

Jeff,
I see on some other threads that you had stated you had the Nelson tune. Would you recommend BB over Nelson?

Yes. Both are great tuners, but in my experience, Justin is far better to work with.

ajswenson · February 15, 2009

I had my GMT900 08 Crewcab VMax for about 2 weeks now and I am disappointed with some things about it.

One is the driveability really is crappy. I don't know if it's just my truck or all of the VMax trucks. But, the idle, off idle, and low throttle response is as bad as an old carbureted engine with a plugged low speed circuit. The engine idles rough and transitions poorly and falls flat when you step on it.

Any input from you other VMax owners would be appreciated. Is this typical of all these new VMax engines? If so, are there some aftermarket cures? (Supertune, etc)

Hey Chuck, what kind of idel issues are you having. When I stop at lights or when I'm sitting in traffic mine idles sort of rough. I was thinking that it was due to my CAI and that Justin would straigten things out during my tune, but since this thread has already started, are there any others out there with a rough idle in their vortec max?????

punmax · February 15, 2009

I had my GMT900 08 Crewcab VMax for about 2 weeks now and I am disappointed with some things about it.

One is the driveability really is crappy. I don't know if it's just my truck or all of the VMax trucks. But, the idle, off idle, and low throttle response is as bad as an old carbureted engine with a plugged low speed circuit. The engine idles rough and transitions poorly and falls flat when you step on it.

Any input from you other VMax owners would be appreciated. Is this typical of all these new VMax engines? If so, are there some aftermarket cures? (Supertune, etc)

My truck idle's very rough..cruising at about 10KM/H with the foot off the pedal, as soon as I give it some throttle the truck jerks and rpms shoot at 2000-3000. Also the transmission shifts are hard. I think the 4.10 gears play a big part in these problems? Driving my dads Ram, it's smooth as silk. Might as well say this too, Dad and I raced from 30KM/H and my truck totally killed it!

07.5_Z71 · February 16, 2009

I don't have the Vmax, just the 5.3 and my sierra idles a little rough while sitting at red lights or just in park idling. When it does this I can visibly see the rpm gage jump up and drop back down and can feel the vibration in my seat. I ran by the dealership the other day and talked with mechanic about it and he said it is a known issue, they supposedly can do something about it and told me to make an appt. I will be bringing it in asap... Sorry don't have an in depth fix for ya...

Spurshot · February 16, 2009

Tony,

It would idle so that if you let off the brake just a little at a stoplight, the truck would do these little bumps forward. It would change rpm enough to see it on the tach going up and down.

Since the mail order Blackbear tune, it's improved somewhat. It's still not smooth, but I don't know if some of it is the cam of other problem.

Justin from Blackbear will be out my way next month and I'll have him put it on the dynomometer and see if he can fix some of the little things.

ajswenson · February 16, 2009

Tony,
It would idle so that if you let off the brake just a little at a stoplight, the truck would do these little bumps forward. It would change rpm enough to see it on the tach going up and down.

Since the mail order Blackbear tune, it's improved somewhat. It's still not smooth, but I don't know if some of it is the cam of other problem.

Justin from Blackbear will be out my way next month and I'll have him put it on the dynomometer and see if he can fix some of the little things.

Mine does the exact same thing. I've been thinking about bringing it to the dealer, but haven't yet. Glad to hear someone is having the same issue. I'll let you know if I figure anything out.

brianfenst · April 17, 2009

My 2009 6.0L Suburban has 400 miles on it (Just got it last week). Its going back to the delear Monday for this same problem. We will see if they can do anything about it. At least I know I not crazy noticing these issue. The descriptions of the probelm sound exactly like my problem.

ajswenson · April 17, 2009

if anyone has found a solution please share...I'm having a tune done in about a week and would really hate to have to bring it in after the tune is done and risk the dealership finding out about it

Draenor · April 17, 2009

if anyone has found a solution please share...I'm having a tune done in about a week and would really hate to have to bring it in after the tune is done and risk the dealership finding out about it

Get spare modules.

VMax2007 · April 17, 2009

if anyone has found a solution please share...I'm having a tune done in about a week and would really hate to have to bring it in after the tune is done and risk the dealership finding out about it

Justin IS the solution.

66nova · April 17, 2009

if anyone has found a solution please share...I'm having a tune done in about a week and would really hate to have to bring it in after the tune is done and risk the dealership finding out about it

Justin IS the solution.

+1

No more driveability issues after Justin worked his magic. Very throttle responsive, downshifts when I need it, does not idle as rough and screams when I floor it.

Darkanion · April 17, 2009

if anyone has found a solution please share...I'm having a tune done in about a week and would really hate to have to bring it in after the tune is done and risk the dealership finding out about it

Justin IS the solution.

+1

No more driveability issues after Justin worked his magic. Very throttle responsive, downshifts when I need it, does not idle as rough and screams when I floor it.

I thought it was your wife who screamed when you floor it???