Before I place a call with Quadzilla tech support, I'd like to explain my surging issues and see if anyone else has had the same issues and if so, what you did to resolve them. Some of my surging issues are only noticeable when pulling my 20' bass boat (~2800 pounds). On all tunes, setting the cruise control eliminates the surging.

Stock Aggressive

• Unloaded: Slight surge between 1500 - 2000 RPMs. Surge is minimal, but it's there.
• Pulling the boat: Surging is noticeable while trying to maintain speed on a slight incline (1500 - 2000).

HRVP44

• Unloaded: The surge is more noticeable than the stock aggressive. If I get on the skinny hard, there's no surge, but when I try to ease through the RPM range, I notice the surge.
• Pulling the boat: Surging is noticeable while trying to maintain speed on a slight incline (1500 - 2000)

Small Injectors

• Unloaded: No surging detected, but no "seat of the pants" feeling like the stock aggressive or hrvp44 tunes. Actually it's not much better than stock until I get in the higher RPM range.
• Pulling the boat: Surging is noticeable while trying to maintain speed on a slight incline (1500 - 2000).

Large Injectors

• Unloaded: Same as small injector tune.
• Pulling the boat: Same as small injector tune.

Has anyone experienced these issues? BTW, It's been 18K miles since my last APPS reset and new VP44 install.

 

Why not go to the website and download one of the new tunes?

 

I will. Do the new tunes address surging issues?

 

File Name: XZT+_1000
UPDATED 1/28/2008
Models: DXZ29802
Software Version: 20080128
Feature Code Enabled: XZT+1000

Features:
NEW Factory Tuning file that all XZT+ Modules are shipped with

After updating with this file you will now have a feature code that is not enabled from the factory

Eliminates any and all surging on both automatic and standard transmission trucks

 

I've tried the 1004 and 2004 tunes and still have surging on both. It's more like a jerky feeling as I accelerate. The 2004 is more noticeable than the 1004. I can tolerate the 1004 surging, but it's enough to bug me. I don't feel any surging in the fuel saver or off positions.

Is there something wrong with my truck that's being exaggerated by the XZT? Where should I start looking? The truck currently has 170K on it. At 156K, I did the following:

• Replaced the VP44
• Removed the stock LP and installed a walbro 392 with relocation kit and big lines.
• Installed FP gauge - Currently running 18-20 psi at the pump
• Replaced the IAT and MAP
• Adjusted APPS and reset APPS

 

I had some surging with the old aggressive tune, but since I downloaded the 2004 tune, there's no surging at all for me.

 

I had a customer call in and say that he thought he had some surging or jerking. He said it was that he had a bad u-joint.

Seems a little off the wall but, I guess the added power made it jerk or something with that bad u-joint.

 

the XZT+ surging problem was more at crusing not on acceleration. you can ushuly get it to stop when you accelerate. i think you have something elce going on.

 

That was my experience with the previous tunes. I only felt the surging while cruising. But, with the newest tunes, I feel it while accelerating and cruising.

Any suggestions on where I should start looking?

 

well watch your tach, does it jump up and down when its surging?

 

Mine surges also I have the 2006 download love the box But I just leave it on the timing mode. I will say the new tune does it less than the old tune I find my self turning the banks off and trying to run the xzt+ box when it starts to buck I let off the go peadle and re apply seems to go away for little bit.

 

The tach does bounce slightly during the surge. I'd say around 25 rpms.

One thing I have not tried yet is to set the cruise and see if it still surges on flats and on hills when it has to accelerate. I know with the old tunes, when I set the cruise, the surging was gone. Does anyone think it could be my APPS? And if so, would a diesel shop be able to test it?

 

have you already tryed reseting it, and re adjusting it?

 

Yes. As stated above, I adjusted and reset 15K miles ago. I'll go ahead and perform an adjust and reset again just to eliminate that as a possibility.

 

Quad or anyone else.

Does anyone have a copy of the LARGE InJ tune they can post..the one from 10/01..this one worked best for me..the new tunes surge all the time..especially with the cruise on..please post the old one if you can or email it..thanks.