Need some help with a tune
06-21-2011, 02:19 PM
#1
Need some help with a tune
A friend of Royces is having major issues with his truck. It's a 99 Silverado with a 6.0, MS3 cam, 8.1 truck injectors, and bolt ons. It has an aftermarket converter as well. I don't have a decent PID list as I am using a new laptop, so I used the default LS2 PIDs. If any of you wouldn't mind taking a look at the tune/log, I'm sure he'd appreciate it.
Truck is running rich, seems to be missfiring, has trouble idling both in park and in drive after letting off throttle. At idle it might be showing excessive knock in the log due to a worn motor mount letting the longtube contact the frame.
Truck is running rich, seems to be missfiring, has trouble idling both in park and in drive after letting off throttle. At idle it might be showing excessive knock in the log due to a worn motor mount letting the longtube contact the frame.
Last edited by 00ChevyScott; 06-21-2011 at 02:50 PM.
06-21-2011, 09:31 PM
#5
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Has the RAF tuning been done to get the idle airflow in line with what the engine is wanting? Also injector data is off for those injectors, I see the injector flow rate table has been changed but the voltage offsets, short pulse adder, min. pulsewidth are still the stock values for the injectors that came stock in that truck, injector flow rate even looks a tad high for those 8.1 truck injectors. Those 8.1's flow right at about 30 lbs, I believe if my memory serves me right in a stock tune file for a truck with the 8.1 the IFR should be at something like 29.9. I'd find and pull up a stock tune file for any stock 8.1 truck tune file and get all of the right injector data copied over in that tune for starters.
I would also add maybe a couple hundred more rpms to the idle tables as well, that MS3 is actually a pretty healthy cam and the desired idle speed tables in that tune are actually pretty close and just slightly larger to what I have mine set at in my truck with my smaller 224/230 cam. After getting all of the correct injector data in the tune I would revisit the VE table. Then do your RAF tuning, krambo's got a very nice detailed write up on this as a sticky here in the tuning section!
After you get the idle airflow right and whatnot you could probably even drop the idle rpms back down some if the guy wants plenty of lope at idle but until then like I said I would definately add 200 more rpm or so so you don't have the truck fighting you and wanting to die while you are trying to get the other bugs worked out.
I would also add maybe a couple hundred more rpms to the idle tables as well, that MS3 is actually a pretty healthy cam and the desired idle speed tables in that tune are actually pretty close and just slightly larger to what I have mine set at in my truck with my smaller 224/230 cam. After getting all of the correct injector data in the tune I would revisit the VE table. Then do your RAF tuning, krambo's got a very nice detailed write up on this as a sticky here in the tuning section!
After you get the idle airflow right and whatnot you could probably even drop the idle rpms back down some if the guy wants plenty of lope at idle but until then like I said I would definately add 200 more rpm or so so you don't have the truck fighting you and wanting to die while you are trying to get the other bugs worked out.
Last edited by KLUG'S SS; 06-21-2011 at 10:05 PM.
