"Limp mode" hesitation on an 8.1 BB

[70Camaro406]

I have an '04 Suburban 2500 with the 8.1 L BB. I've had the Hypertech programmer on it for 5 years, but decided to ditch it in favor of a Predator U7193. It ran great before, but I wanted to do away with the torque management, since it is very intrusive on the BB. Anyway, after I installed the 87 tune, and disabled the TM, it developed a hesitation around 2000 rpms, almost like rev limiting itself there, then after more throttle, it would rev up beyond that. It even would go into limp mode a little after driving it a around. I've read on here that some of you download some engine info while driving, and I was going to get the PC interface, U7778, and do that myself, but I wanted to post here first to see if there is anything I need to do before I do that. Any ideas guys? Thanks, Wayne

[mikel]

Start by uploading a copy of the stock tune and the last tune written and post them here please.

[70Camaro406]

Do I do that by using the pc interface tool, U7777 or U7778? If so, I'll order one today.

[mikel]

U7778 is usb to serial, best option.

[70Camaro406]

Okay, thanks. Ordered the U7778. Will post back up after it arrives.

[70Camaro406]

Well, I received the interface, and I downloaded both tunes, the factory (backup) and the current (Diablo 87). Let's see if I can get them on here now...

Predator U7193x
v.9r11
2004 Chevy Suburban 2500, 8.1L

Alright, I added the files as attachments. Let me know if I need to email them instead, or if I need to do a Data Log. I really appreciate the help.

Also, while driving, I notice a great improvement in power, but a few times a day, I'll notice that it loses ALL it's power under part throttle. Even if I give it a little more thottle...nothing. I have to floor it to get it to "come alive," then it's okay. Other times, if I can't floor it, I have to lift a little to let it shift, and then it's game on again. Just thought the extra info would help.
Thanks again,
Wayne

[bbyukonxl]

Get a custom diablew tune from lew "06montess" I have 8.1 Yukon and huge difference from stock tunes

[06MonteSS]

Brad!! how's things man??! haven't seen ya around/online in a while... glad to hear the custom tune is still kickin' ass for ya!!

[70Camaro406]

I did a data log yesterday. I'm in the process of getting it on here...should have it done later this afternoon.

bbyukonxl - I checked into that and will probably go that route soon. I just want to get it to run correctly on it's own first without have to spend more money over the price of the programmer and the interface kit. Plus, I want to upgrade the exhaust and intake so I get the Diablew tune right the first time.

Thanks guys.

[bbyukonxl]

yeh diablew if only way to go!!! like a new truck.definately data log with predator hooked to laptop if you can.way easier and you see live data and know that you are recording. Lew took alot of time dialing my truck in and gettin all the knock out of it.top notch service! Lew just waitin for this warm weather then hit you up with log and see how she looks.thanks

[70Camaro406]

Okay, i did two logs. The first one I started on the exit ramp to our local bypass, 65 mph 4 lane, and the Predator recorded around 5-6 minutes worth of steady cruise. This road has slight grades both incline and decline.

Then yesterday, I did another with both the Predator and the laptop hooked up with Dataviewer running. This one was a steady cruise at 60 mph, then a stop at a stoplight, then a wot start till 70-75ish, then back down to 60ish then finished...around 6-8 minutes. i hope these are helpful.

Under the wot start, I watched the timing drop all the way down to as low as 15 degrees. I guess that can be one of the things to change. I'm not so sure as to what the optimum fuel tables and ramps are or should be...that's why I am asking the experts.

Thanks Lew and Mikel for your help.

[70Camaro406]

Mike, I'm still having trouble uploading the tune from the laptop to the Predator...having the code 27 error still. I did a search and saw where someone else from the Predator Ford Gas section had the same problem. Vas gave him some simple tips, and then he posted that it was resolved. I posted an inquiry on that thread as to what it took to resolve it, but no responses yet.

I have the most current DSDL program, from 2 weeks ago, and for my U7193 I have the v.9r11 version. The only thing I can't change from his ideas is the compressed file option. Mine is automatically checked and is gray and can't be unchecked. Is there any other things that I can check? Could it be a corrupt file or incompatibility issue? I'm running out of ideas.


Thanks

[mikel]

Have you loaded custom tunes in the past?

[70Camaro406]

No, I haven't. After the first few times of it not taking, I tried uploading the current tune and backup from the laptop to the Predator and they took. Then I saved them off of it again, and tried the custom tune and got the same error.

[06MonteSS]

what tune is it that you're trying to upload into the predator man?? did you have a custom tune done for your truck/predator by a diablo CMR tuner???

what is the custom tune file???