Hey guys. I am pretty green at tuning and have been working on this tune for a while now but have hit a wall. The truck is a dog off the line when I stab the throttle. It lets out a nice small puff of smoke so I dont want to fuel it harder and it pulls great after a couple seconds but it doesnt pull like I want from a dig. Any other criticism about the tune would be greatly appreciated. The truck is pretty much stock.
LBZ tune help
- Thread starter 1972chevy
- Start date
If your converter is too tight , it will be hard to tune that away , so I suggest you call Evan , Mike L , Tony , Caleb , these are the ones I know , depending on where you live we are blessed to have great Allison and Duramax people around the USA and Canada . Once you get the right tranny matched with the right converter , it feels like you added 100HP !
The truck is basically stock so I dont think it is a converter or trans issue. I am sure that would still help though. The more I look at my logs it seems like its taking a long time for boost to come on but I could be wrong. I am posting the most recent log I have. let me know what you think.
I was going to mention the turbo vane or sensor , till I looked at your logs , not that ! What size are your tires ? Stock 373 rear ?
My computer is KIA right now, so I can't see your tune right now. Where is your maximum vane pos set at in those lower rpm spool areas, and during all of this how is smoke output?
The max vane position is the stock table at the moment. The truck puts out a small puff of smoke when I first lay into it but that's about it for smoke. I am starting to think I may have a boost leak. I can't hear one but in the log it takes a long time for boost to come up and even when it does the boost is low and the vanes stay fairly closed the whole time. That being said would you suggest raising the max can position to help low end spooling?
How many miles on the truck ? Do you still have a cat ? do you have a lift pump ? How long have you had this problem ?
There is 270,000 km on it. I'm not sure what that would be in miles. There is no cat. I got the truck fairly recently. I didn't ever really bag on it with the stock tuning. I started tuning it pretty much right away. I've been fighting this ever since. No there isn't a lift pump on the truck.
Is the fuel mixture table still stock? I know if you put that table too far to the lean side, spool up is very slow.
You could try adding 7%to the max vane table from 1000rpm-1800rpm.
You could try adding 7%to the max vane table from 1000rpm-1800rpm.
You need to start logging and see how the changes you make affect it's performance.
The first suprise I learned while tuning was when I opened the vanes up more durring spooling in the stock table. My truck did 0-80mph 0.2 sec. faster then before.
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The first suprise I learned while tuning was when I opened the vanes up more durring spooling in the stock table. My truck did 0-80mph 0.2 sec. faster then before.
Sent from my SAMSUNG-SM-G900A using Tapatalk
I added a few pids to better help you map your log in your tune. (attached)
If you think you have a boost leak I can walk you through how I made my own Boost leak tester tool with parts from Home Depot.
If you think you have a boost leak I can walk you through how I made my own Boost leak tester tool with parts from Home Depot.
It looks to me like you either have a serious restriction somewhere in your intake tract or your map sensor is defective. You are sitting at 12.8 Baro and 10.7 MAP at idle just before you stab the accelerator pedal.
Actually, looking closer at the log, I'm going to guess some sort of restriction in an intercooler tube or something maybe. You can see the MAP steadily dropping at idle before you drop the hammer. Maybe a rag or something in an intercooler tube.
Actually, looking closer at the log, I'm going to guess some sort of restriction in an intercooler tube or something maybe. You can see the MAP steadily dropping at idle before you drop the hammer. Maybe a rag or something in an intercooler tube.
Thanks for all the help guys. That gives me a lot of great info to define my tuning once I get my issue figured out. I appreciate it. I am hoping over the next couple days I'll have a chance to check for restrictions and boost leaks. Thanks for the idea JoshH I haven't thought of a restriction. Thanks for the PIDs duramaxnate. That looks a lot more useful than I was logging. I think I have got the boost leak tester figured out but thanks. I will keep you guys posted on what I find.
Well I have taken apart all my cac piping and intake but can't find any restriction. The map sensor was reading below baro when with the truck off so I changed the sensor. Same thing with the new one though. I did find a couple of boost leaks. Fixing them seemed to make a big difference with how the truck drives. No more surging and crap like that. Still falls on its face a bit when I stab the throttle from a stop. I'm not too sure where else to go from here.
